High Definition Television In 2009
by Dawn McGatney
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Kaluza Solves Einstein In 5 Dimensions And Watches “Maxwell's Wonderful Equations” Falling Out. (16:9, 1080p) |
To Diane, From Dr. Steve...
“And when you are old and gray, and filled with digital sleep,
And nodding by the fire, take down this book,
And slowly read, and dream of the soft look,
Your analogue blue eyes once had, and of their shadows so deep” -Yeats
And your sons and your daughters shall prophecy,
Your old men shall dream dreams,
Your young men shall see visions; - JOEL 3:1There are more things in Heaven and Earth, Horatio,
Than are dreamt of in your philosophy; - HAMLET 1:5This film has been modified from its original version,
It has been formatted to fit your screen; - ANALOG 2:3
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‡Dr. Steve Goldbloom, our technical consultant for this article, received his graduate degree from The Whiting School Of Engineering of The Johns Hopkins University; he holds an FCC first-class license with radar endorsement. He has been employed as both an FM transmitter engineer and a color TV broadcast engineer. “Dr. Steve” presently serves as Executive VP of Precise Networking Solutions.
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Hi-
I'm DAwn's dog Wolf... A gift from some jilleroo... way back... the year that she
spent the summer out on that sheep station.
SO... Why am I writing on High Definition Television?
First, DAwn asked me to... And it's very difficult to say "No" to this
exponentially distributed woman. And so this article will be my "Opus #5".
Second, it seems that the better folks understand how HD and HDTV receivers
really work, the better they can make an informed decision on their home
networking solutions (e.g., FiOS MoCA), the better to learn networking.
Third... there is so much Mis-Information about Digital TV and High Def
floating around... on the Net, in reputable magazines, in well-regarded papers.
I've been explaining things to Netizens for over ten years now, beginning with the
Net itself; and so your dog Wolf has a fairly good idea how to separate the data
packets from the background noise.
Fifth (there is no fourth) and foremost, because Precise Networking Solutions
(aka "Boss") has been getting so many questions from its clients asking about HD and
HDTV sets, and what they must do to prepare for the end of analog.
"Wolf..." PNS demanded of us, "write one of your Dog Wolf© articles
for us, write about High Definition Television (HD) as it existed in the months before
and after the June 2009 transition... both the technology and the politics. Write
something that we can refer our clients to, and be certain it's 100% accurate. (We have
a sterling reputation.)"
To be honest, I'm curious to find out exactly what makes up High Definition and the
HDTV sets that are taking up so much space and so many dollars in the Big Box Stores.
And with luck and a favorable wind, we should complete "Opus #5" by June 2009, just
in time for the Big transition.
Like some fine wine, my dog Wolf pages improve with age and with your feedback...
from all the knowledgeable gurus out there in cyberspace. So below is a button to our
e-mail address for your comments and corrections. ¿Está claro?
(Since its inception in July 2007, our site has become very popular among folks
like yourselves. 78% of individuals looking for information on the US digital transition
and/or High Definition have visited this Web site five or more times. And so we're
continuing to work hard to expand this information base.)
So let the adventure begin... and Happy Halloween. This year, I think I may dress
up as a Trellis Encoder.
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Some Recent History→ Finally, Someone Got It→ The end of analog TV was delayed by a special act of Congress. Sen. Rockefeller's statement acknowledged that the US was not ready; at least 10 million antenna-dependent viewers (especially the elderly, Hispanics, the poor, and the technically challenged) would have screamed bloody murder unless the demise of analog television had been delayed. In early December, Congress passed a bill requiring analog broadcasts of public safety announcements and information about the digital transition for 30 days after 17 February. (President Bush actually signed the bill into law on 23 December.) The following day, the FCC called on broadcasters to try to assure that at least one analog TV station in each market kept its signal going for 30 days past the 17 February cut-off date to provide both emergency information and Digital TV educational information. The FCC also said it would look for ways that stations could provide this "NightLight Service", including encouraging low-power stations that were remaining analog to transmit the information. Channels to be used for the analog "NightLight Service" would be confined to 2-59 to avoid interferring with the new public safety spectrum (channels 63, 64, 68, and 69... although these were not even close to being ready to start public safety broadcasts in the first place). Chaos. The program, actually called the Analog NightLight Program, would have covered only 310 of the 1,749 full-power
US TV stations. The prerequisite for inclusion in the program→ The "NightLight stations" would be at least
164 miles from any digital TV stations that were broadcasting on the same channel. (Low-power analog TV stations 164
miles from a digital station? This was probably the supreme example of the total lack of comprehension by the then-FCC
leadership.)
Said Dish Network (Satellite) CEO Charlie Ergen, “I think it's likely that the Federal Government will be forced
to delay the digital transition because of a lack of preparedness. I've been going to Washington for a long time now, and I
think if the Obama Administration comes in, and if they see that the transition is not ready, and that consumers could
lose their signal, Congress is going to go all out to protect these consumers and delay the transition date,” Ergen
said.
January Early Birds→ Hawaii made the switch to digital-only TV earlier than most of the rest of the country. The Hawaii Association of Broadcasters had announced that the state would go digital-only on 15 January 2009, rather than waiting until 17 February. The Association said the earlier switch was needed after the US Fish And Wildlife Service recommended that broadcasters "deconstruct" their analog facilities on Maui earlier than planned in order to avoid the Hawaiian petrel breeding season in the area. (You can't make this stuff up... Yes, petrels are tube-nosed seabirds. Hawaii was moving to digital-only TV before the rest of the nation because of the Hawaiian dark-rumped petrel, an endangered bird. Broadcasters and park rangers wanted to take down analog transmission towers on the slopes of Maui's Haleakala volcano before the bird's nesting season. Hawaii’s full-power stations are now broadcasting digital-only signals to viewers on the Big Island, Maui, and Oahu. Kauai is served by low-power translators, and it will remain analog until some undecided later date.) 15 January→ Hawaiians said aloha to analog television. The shutdown of the old analog TV broadcasts
happened at noon. A special TV help center was flooded with calls. Households that needed but failed to buy digital
converter boxes missed Thursday night shows. Others who bought the $50 to $70 converter boxes still found that they lost
channels because the digital signals didn't reach all the places previously hit by analog broadcasts.
Most/Least Prepared Cities (Nielsen Co - 27 May 2009)
What About UK?→ The UK plans to end all analog over-the-air TV by 2012, replacing it with digital. The switchover began last year (2008). The Border area has already started to make the switchover and plans to be fully digital by 2009. Unlike the US, the UK is NOT switching virtually everyone on the same date. (Makes some sense, ey?) Here are the specific dates→ Border starts in November 2008 and finishes in 2009. US vs UK→ A Contrast→ As each section of UK converts to digital, eligible folks (e.g., the elderly) contribute $40 (USD); in return, a government technician comes to your home. No need for advertising, playing with converter boxes and/or expensive antennas. (Ok, true, folks in the UK (generally) pay an annual license fee to operate their TVs.) This help is voluntary; if you want it, it's there, but it's not forced on you. What Do Eligible (Over 7 Million) British Citizens Get?→
What About Canada?→ Back in January 2008, 18 Canadian TV stations were broadcasting in both analog and digital on pairs of channels; most of the digital stations were in Ontario. The Canadian Radio-television and Telecommunications Commission (CRTC) has announced that it will force conversion to digital TV by 31 August 2011 (except in northern and remote Canadian areas). Small communities may find that they no longer can receive free over-the-air TV broadcasts. If you're Canadian and are watching American channels over-the-air, you'll need a converter box by 12 June 2009 at the latest. You may need to import the converter from the US (it is legal), since the boxes are not yet widely available in Canada. Note that Industry Canada says it has no plans to help Canadians defray the cost of converter boxes (no $40 coupons). Canadian satellite subscribers and digital cable subscribers (those who use a set-top digital cable box) will not be affected, but analog cable subscribers (who plug the cable from the wall outlet directly into their TV set) will eventually need to get a digital cable box. (After 2013, or when 85 per cent of its customers are digital, Canadian cable operators will no longer be obliged to carry an analog signal.) So your Canadian cable bill might well go up at that time. Of course, Canadians can always buy a new TV set with an ATSC digital tuner and continue receiving American (and Canadian) over-the-air digital broadcasts.
NASCAR→ Hoping to "rev up" awareness for the transition to digital TV, the Federal Communications Commission actually put up $350,000 to sponsor NASCAR team No. 38. (We're not kidding.) Starting 19 October 2008, racing fans were able to see Yates Racing's Ford Fusion whip around the track with the date of the February transition and the words "Are you ready for digital?" on its hood. You also may recall that the Ford Fusion didn't fare very well in its inaugural run in the Tums QuikPak 500 in Martinsville, Va. It finished in 32nd place after going "hard into the wall" on lap 485 (according to NASCAR.com). David Gilliland, the driver, said on his Web site that the resulting damage was “just too much to be able to repair in time.” And so a taxpayer watchdog group named then FCC Chairman Kevin Martin "The October Porker of the Month", blaming the Republican for the FCC's sponsorship of Mr. Gilliland, like Mr. Martin, also a fellow North Carolina native. Trivia→ The Digital TV Transition Ford Fusion next appeared at the Phoenix International Raceway on
9 November; and then at Homestead-Miami Speedway on 16 November. And for the second straight time, the
FCC-sponsored NASCAR auto, designed to promote the then February transition, was involved in an accident. But former FCC
Chairman Kevin Martin said that's “a good thing. Except for the cars that win the races, the cars that are in wrecks
get a lot of attention,” Martin told reporters, according to Reuters.
More Trivia→ Martin, who is from North Carolina and reportedly has plans to run for office there someday, chose the car driven by fellow North Carolinian David Gilliland as the FCC-sponsored vehicle. Citizens Against Government Waste said Martin picked his home state's driver for political reasons. (The former FCC chairman also chose Wilmington, North Carolina, for the first test of the Nation's switch to digital.) Martin had been appointed in 2005 by President Bush to head the FCC, five years after he worked as a legal counsel for Mr. Bush's presidential campaign. He also worked on the Florida vote recount, and the fruits of his labor... newspaper front pages declaring Bush's victory... lined the hallway leading into his office. (Sound a bit like FEMA? Before joining FEMA, FEMA head Michael Brown was the Judges and Stewards Commissioner for the
International Arabian Horse Association. Mr. Brown supervised FEMA activities during the firt days after Katrina.)
No One In Charge?→ Former FCC chairman Kevin Martin rejected charges on Capitol Hill that his agency and the Bush administration failed to take command of the conversion to digital-only TV. “There is no confusion at the FCC. We are committed to putting policies in place to ensure a smooth transition,” Martin said. Martin’s response came after a Government Accountability Office (GAO) official said in Senate testimony that no one at the FCC (an independent agency with leadership picked by the President) or within the administration itself, asserted leadership authority. “It’s pretty clear to us, based on the initial work we have done, that there is no one in charge,” said Mark Goldstein, the GAO’s director of physical infrastructure. Goldstein indicated that the FCC’s ability to take charge was hampered by internal disputes. “There seems to be confusion even at the FCC, between the chairman and some other commissioners, regarding what
its responsibilities are for the transition,” he said. Some of the confusion found by the GAO could be the results of
the 2005 law that created the analog TV cut-off. The law ordered the Commerce Department’s National Telecommunications and
Information Administration (NTIA) to create and supervise a $1.5 billion program to subsidize digital-to-analog
converters boxes and spend $5 million on public education. $5 million?
The 2009 Federal Communications Commission→ Nearly 2% (roughly two million) of US households would have lost their TV signal had 100% of the US switched to digital in mid-February, according to federal regulators. Many television stations needed to shift their broadcast "footprints" by changing their transmitter locations, antenna patterns, and/or power levels. (The FCC never demanded that TV stations replicate their analog coverage with their new digital transmitters.) Those viewers who could no longer pick up a picture just would have been... well, out of luck. Rule Of Thumb→ If you get a fuzzy analog signal, you probably will not get any digital picture. This will mean that some folks will need more powerful antennas in addition to converter boxes to continue receiving certain channels. In an FCC report released in late December 2008, the FCC said 319 of the nation's 1,749 full-power television stations, or 18%, would have had a digital signal that reached at least 2% fewer viewers than their analog broadcasts. While the digital transition was supposed to be the greatest thing since sliced bread, many pushed for the change to
digital hoping that the FCC would make a killing auctioning off freed up channels. (The channels primarily are "freed
up" because the digital signal is very tightly squeezed into existing 6 MHz channels by Nyquist filtering techniques,
causing lots of transmission noise and errors and requiring very precise sampling times.)
As of October 2008, millions of Americans were still confused about a number of things related to the digital TV conversion. A study by Consumer Reports showed that there were all sorts of misconceptions out there. Among them→
The study found that about 17 percent of Americans who lived in a home with a television had at least one set that would be affected by the change to digital broadcasts, and that 13 percent relied on over-the-air signals. That meant that some 19 million people needed to take some kind of action. However, the TV broadcast industry did have two traveling "road shows" (large vans) going about the country, visiting county fairs and air shows and such, not to mention over 200 volunteers in a "speakers' bureau", explaining to groups (especially the elderly) about the digital conversion and converter boxes. Something sound wrong? By late October 2008, analog transmissions in major markets began cutting away from normal programming to display a message on the viewer's screen that said something like, "You need to do something with this analog set before February." For example, on 28 October 2008, if you received your TV programming from a New York City area station, and if your television received its signal through an antenna, and if your set was analog (old) and not digital (new), your screen at 5.59 PM no longer displayed the program you had been watching. Instead, a message was shown for a few minutes alerting viewers to the digital conversion and imploring them to get a converter box. So why then did DirecTV subscribers "fail" these and similar tests? A statement directly from DirecTV's corporate office in Greenwood Village, Colorado, explained why some local stations may have "failed" recent digital signal tests→ “Some local channels have been providing us with an analog signal that we have been converting to digital. When the station tests its digital signal, this is a different signal than the one it has been sending us,” the statement reads. “We're working with each station to change over to their digital feeds over the next few weeks (early 2009)”. (Got that? Think broadcast stations were 100% ready on 17 February?) “Even though it may appear that your system failed the preparedness test, rest assured that, as long as you get your local channels through DirecTV, you have nothing to worry about after the digital transition.” (Anna Mary Francis, service representative for Dish Network in Englewood, Colorado, said the same is true for that satellite system.) But→ Both companies noted that any "off-air" channels... those not received as part of the subscriber network... will require a converter box. Both companies also offered various conversion "packages" which included local programming options. Yet Another Problem→ If you had already purchased and installed one of the converter boxes with analog pass-through, and if you were watching a full-power analog station, then you received the "Do Something Fast" message on your screen anyway, when in reality your TV and your converter box were fine, you needed to do nothing. This whole thing reminded us of the Y2K build up... only it's not the world ending, it's your television going dead. (Of course, with today's "TV is the #1 babysitter" generation, we can see where that might come across as an apocalyptic event.)
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 Dr. Michael J. Copps Acting FCC Chairman 2009 |
The FCC's Final Rules→ The FCC issued its rules for the remaining weeks of the transition leading up to 12 June. Another 421 of the nation’s 1,749 full-power TV stations pulled the plug on analog on 17 February. 158 stations have requested permission to cease analog broadcasts between 16 April and 11 June. The remaining 971 stations will transition on 12 June. All TV stations still transmitting an analog signals are subject to these final FCC transition rules→
Signal loss→ Stations must provide on-the-air and other notifications of potential signal loss if 2% or more of their analog viewers are expected to lose service, regardless of whether or not these stations gain viewers in other areas.
Antennas→ All stations must include information about the use of antennas as part of their consumer education campaigns, such as including additional information if a station is changing from VHF (channels 2-13) to UHF (channels 14-51); or if viewers may need additional or different equipment to avoid loss of service.
Scanning→ Stations must inform and remind viewers about the importance of periodically using the rescan function of their digital televisions and/or converter boxes. During the time around the conclusion of the transition, many stations will be changing their service areas and the broadcast channels of their digital transmissions and going to new antennas. As a result, viewers will need to rescan periodically during this period in order to ensure that they are correctly receiving all the digital broadcast services available to them.
The Golden Rule→ Said Acting FCC Chairman Michael Copps, “The guiding principle here is simple — consumers deserve to know the truth. They will forgive a lot, but they won’t forgive being lulled into a false sense that the transition will be less disruptive or less expensive than it turns out to be.”
Nielsen reported in March 2009 that 3.9 percent of US households still are "completely unready" for the digital transition, down from the 9.8 percent that were considered completely unready in May 2008. Not surprisingly, the National Association of Broadcasters (NAB) is disputing Nielsen's figures and the methodology behind them. In a letter to Nielsen, NAB president and CEO David Rehr said the reports classify as "completely unready" households that have purchased converter boxes but not yet hooked them up, and households that have a converter box coupon they have not yet redeemed, or have applied for a coupon but are waiting for it to arrive. (Yes, how strange.)
The new FCC rules also establish procedures for stations to terminate analog service before 12 June, if they so choose. Such "early bird" stations are required to notify the FCC by 17 March, though granting permission to terminate analog before 16 April is unlikely. “However, non-commercial stations experiencing significant financial hardship may terminate analog service beginning on 27 March”, said the FCC.
Fox, CBS, ABC and NBC affiliates that want to shut down before 12 June must ensure that at least 90% of their analog audience will continue receiving TV service from another major affiliate. Stations of such affiliates can either distribute their regular programming lineup or air enhanced "NightLight Service" of news, public affairs, and emergency information.
In the event that 10% of analog viewers of a major network affiliate lose service from all major network affiliates in their market, one of those stations has to provide assistance and public outreach, or all can do so collectively.
Broadcasters may terminate their analog broadcasts at any time of day on their final end date, as long as they first notify the FCC. They do not have to wait until 11.59.59 PM on 12 June.
And if you're curious as to when a particular full-power station is killing its analog broadcast, or you'd like to know which channel the station will end up on, or whether a particular station will lose more than 2% of its analog viewers when it goes digital-only (and stuff like this), simply click on this link→
How We Got Here→ High Definition broadcasting was introduced in Japan using the MUSE system, an analog system using compression. In the US in the 1980's, both CBS and RCA developed analog HDTV systems that were compatible with existing NTSC TV sets.
But the TV industry made the decision to leapfrog over analog and develop digital television. One reason was to stimulate television manufacturing in the United States. A Grand Alliance was formed within the television industry to agree upon a set of standards and to promote HDTV. The TV industry then lobbied Congress and the FCC for legislation and rules that would foster HDTV, supposedly for the benefit of broadcasters and set manufacturers.
NTSC vs ATSC→ While roaming the highways and byways of High Definition TV, you'll often see these abbreviations→ NTSC and ATSC; no big deal, really. In a nutshell, each of these two abbreviations stands for a committee and for the standards developed by that committee→
The primary ATSC standard in use by US digital TV stations is the "A/53" television standard.
NTSC = Analog Standards = Old.
ATSC = Digital Standards = New.
Digital TV (DTV)→ A system for broadcasting and receiving picture and sound and data using digital signals (0's and 1's), as opposed to analog signals (continuously varying waveform signals) used by traditional TV since the 1940's. With digital TV, the picture and sound to be broadcast are compressed early in the transmission process. Upon reception, the signal must be reverse decoded (de-compressed) by a new and different type of TV set, or by a standard NTSC analog receiver with a converter box costing $40-$90, possibly minus $40 with a US government subsidy coupon (phone 1-888-DTV-2009 for 1 or 2 coupons per household). Or→
To apply for one or two $40-off coupons to be used in the purchase of a converter box, simply click on this link→
Introduced in the late 1990's, with some bugs (e.g., "ghosts"), and then with patches attempting to fix the bugs, digital TV transmissions allow broadcasters, if they wish, to provide TV with higher resolution pictures. The optional higher resolution pictures are called High Definition or HD; broadcast HD pictures are made up of sixty 720- or thirty 1080-horizontal lines per second, compared to thirty 480-horizontal lines per second on the screen for an NTSC analog picture; and HD also contains more picture data on each of its 720 or 1080 lines.
All ATSC digital is broadcast with Dolby sound, with 1-6 sound channels. Digital TV also can transmit multiple programs simultaneously on a single physical (6 MHz) TV channel (this is called "multi-casting"); digital TV, in theory, also has the capability of providing "new interactive services".
Some have likened multicasting to distributing several additional TV broadcast licenses to every full-power TV station, at no charge to the broadcaster. In Other Words→ Although the digital transition has meant cash outlays for stations (digital equipment, tower modifications, etc), it opens up major additional revenue "opportunities" through multicasting. (Every sub-channel multicast is another stream of commercials to be broadcast.)
Most TV stations across the US have been broadcasting television programs in both analog and digital formats for several years now. (We're in "transition"; ever chat with a woman in labor going through "transition"?) 971 TV stations continued to broadcast their programs in analog format until sometime on 12 June 2009. Since that date, all US full-power TV stations have ceased broadcasting in analog. Digital TV alone rules the full-power TV spectrum, channels 2-51 (the so-called "core" TV spectrum).
(Former TV channels 52-67 will go to the phone companies paying the most $$$ (those frequencies are gold); and
former TV channels 63, 64, 68, and 69 will be used (someday, but not now, no one in emergency services is ready) by
emergency service providers; e.g., fire fighters.)
Why do we keep saying "full-power" station over and over?
In the US, there are 1,749 full-power TV stations. They each provide TV to a metropolitan area and beyond. But there also are other kinds of TV stations, stations that are not full-power, stations with transmitters that are not manly and robust. Many folks, even in major TV markets, receive broadcasts from these low-power stations, often without even knowing it.
The non-High-Power TV Stations Include→
- 2,100 Low Power (LPTV) transmitters. A low-power TV (LPTV) transmitter may serve a small town, or just a section of a large city. The FCC created low-power television stations (LPTV) in 1982 to provide locally-oriented television service in small communities. LPTV programming can broadcast satellite-delivered programming services, syndicated programs, movies, and locally-produced programs. Low Power stations are permitted to have a radiated power of up to 3,000 watts for VHF channels (2-13) and 150,000 for UHF channels (14 and up). LPTV stations generally have a coverage area of up to 12-15 miles. Example→ K54FA, San Antonio, Tx.
- 560 "Class A" stations. Created by the FCC in 1999, Class A TV stations are former LPTV stations that now have certain interference protection rights not available to LPTV stations. These stations are similar to LPTV stations, but unlike LPTV stations, they must air at least three hours of locally-produced programming each week and comply with most of the non-technical regulations applicable to full-power stations. Example→ WBXT-CA, Tallahassee, Fla. ("CA" stands for "Class A").
- And 4,400 TV broadcast stations called "translator stations". A TV translator station rebroadcasts the programs of a full-power TV station. TV translator stations typically serve communities that can't receive the signals of free over-the-air TV stations because they are too far away or because of the intervening topography such as mountains. Many TV translator stations operate in mountainous or other remote areas of the US. In the plains and in the South, higher-power translator stations often send out a transmission blanketing an entire state, beaming it from tall towers that may be 2,000 feet high. The Rub→ Some translator stations broadcast with full-power; they are in effect, a "twin".
Especially west of the Mississippi, some states literally have hundreds of translator stations to carry full-power stations into hard to reach locales. These translators, many owned by full-power stations, may convert to digital in June; or they may not. Thus, the tale of non-High-Power TV stations is not a simple one. LPTV transmitters are not required to shutdown analog operation in mid-June 2009, when full-power US TV operators must do so. But full-power translator stations that are used to simulcast another station were, just like any other full-service television broadcasters, required to convert to digital in June 2009.
So exactly why do we bother to mention low-power TV stations?
Many folks, even folks living in major TV markets like Washington, DC, receive low-power TV broadcasts, often without even knowing it. And low-power stations were not required to cease broadcasting in analog by June 2009. In fact, the FCC has not even decided for certain what it wants to do with these stations, relative to digital... or when. This is where things get really messy... messy, that is, if you are receiving a non-High-Power TV station using rabbit ears or a rooftop antenna. (Folks receiving low-power stations over cable or satellite have no problems.)
The Problem→ Many converter boxes on sale block the analog signals from low-power and translator
and "Class A" TV stations. And many of these
Some low-power stations will convert voluntarily to digital, and some will not. If your low-power station(s) has a suffix of "DL" or "LD", then it has already converted to digital voluntarily, and you will need a converter box or a digital receiver to continue watching it.
If your "Class A" station has a suffix of "DC", then it has converted to digital voluntarily, and you'll need a converter box or a digital receiver to watch it.
Translators often have a suffix of "TX." You can tell translators from regular stations by their call letters...
instead of three or four letters, they usually have five characters, including (usually) numbers. Example→
W42AE, Poughkeepsie, NY. But note→ KAMK-LP, in Eugene, Oregon, is a translator station. And full-power translators
like WPBS-TV's (Watertown, NY and southern Canada) identical twin transmitter WNPI-TV have call letters like ordinary
full-power stations.
An NTIA Website (NTIA is an agency of the US Dept of Commerce) has a list of converter boxes which will allow analog broadcasts to pass, eliminating the problem; simply click this link→
Interestingly, the above Web site not only has a list of converter boxes that are available in US retail stores, it also has a nicely formatted list of converter boxes that are not available in US retail stores. (We don't know, ask the Department of Commerce why they listed these.)
Note that if you receive only low-power, or "Class A", or translator TV stations, you needed to do nothing to prepare for the June 2009 conversions; all of your stations may continue to broadcast in analog. At the most, they will simply move to a different channel. However, just to complicate matters, some LPTV and "Class A" stations did convert to digital before June. Or they converted after 12 June. If you know that you watch one or more low-power TV stations, contact the stations or check their Web sites; see what their plans are; you may or may not even need a converter box.
One Comment→ All newer digital TVs (HD and non-HD) also include NTSC analog tuners, so that they can
receive both old analog and new digital over-the-air broadcasts. This is not the least expensive solution, but it
definitely covers whatever TV stations and the FCC can throw at you. If you're flush and confident for 2009 (right),
consider a digital TV (a TV with an ATSC tuner); it does not have to be an HDTV set. Just a digital. Or if you're
a bit more cautious on the economy, get a converter box with "analog pass-through".
Flash-Cuts→ A "flash-cut" is when a TV station changes immediately, with no phase-in period, no testing. Las Vegas in the ether. Trivia→ A station doing a flash-cut, despite the name, may actually take days to convert over to digital. During the conversion, you will normally receive nothing from the station.
What About Flash-Cuts And Converter Boxes?→ Full-power TV stations that planned to flash-cut were broadcasting only in analog until a date near or on 12 June 2009, when they switched to digital. Until this switch to digital, until this flash-cut, many converter boxes were not be able receive broadcasts from such stations, since many converter boxes can receive only digital TV, and they block analog signals. (These are surely exciting times in which to live and view TV.)
Why Didn't?→ Why didn't The US Department Of Commerce simply require that all converter boxes accept both Digital and Analog?→ You actually have to ask? These are the same folks who ran out of money for the $40 subsidy program just after Christmas (under former leadership), after assuring Congress that they had plenty of resources.
To get the best TV pictures, you'll need an HDTV set and an HD signal to that set as input. An HD signal may come from over-the-air (OTA) broadcasts to your antenna, or it may come from digital cable, satellite, or FiOS, or it may come from the new Blu-ray Disc DVD players.
What's HD?→ HD over-the-air broadcasts is a set of 6 of 18 possible kinds of digital television broadcasts specified in the ATSC standards; these top six have a clearer and sharper resolution and a better-looking picture than the 12 other types of digital broadcasts or analog. The sound with digital is the same with all 18 picture resolutions; but only the top six picture resolutions are prime dry-aged NY strip.
HD uses a higher resolution digital video signal; an HD camera at the TV studio generates about 1.5 billion bits per second. This video is compressed by MPEG-2 techniques before being mixed with Dolby sound (compressed by AC-3 (Dolby) techniques); compressed video and sound are then mixed with miscellaneous data before being broadcast.
HD requires new production equipment (new cameras, new sets, better complexions, new switchers, new editors, etc);
however, High Definition is broadcast by the same digital transmitters as Standard Definition video (SD). The FCC is
requiring that all full-power TV stations broadcast in ATSC digital after 12 June 2009. But no TV station is required
to broadcast an HD picture after 12 June... or ever; it is up to the broadcaster whether she wants to broadcast in
High Definition digital; the FCC only requires that the station broadcast
HDTV→ HDTV is the TV set (receiver) that can display HD broadcasts or the new Blu-ray Disc DVDs in all their splendor and detail. An HDTV set also can display Standard Definition (SD) as well as analog. An HDTV set needs a set-top digital box rented from the cable provider, or a built-in QAM tuner, in order to receive HD over digital cable. An HDTV set has one to two million pixels (tiny little square picture elements) on its screen.
If you buy an HDTV set that also has a built-in QAM ("Cable Ready") tuner, and if your cable system is "digital cable",
you can watch all digital programming that is not encoded at no extra charge, and you will not need to rent a
Clear QAM→ Un-encoded QAM digital cable programs sent without charge are often called clear QAM, as in... "Local affiliates of the major networks are often broadcast via clear QAM (free), and often in High Definition, by cable providers".
What's Dolby?→ Whether the video is high-definition (HD) or standard-definition (SD), all US digital
television uses Dolby audio. (There is clout.) The Dolby format of any digital TV broadcast varies from one audio channel
to six-channel Surround Sound (5.1). If you have Blue-ray Disc, you may listen to 7.1 (seven channel) Dolby. Dolby has
sound of CD quality. Dolby 5.1 can be connected to six speakers located around the room if you like; or you can always
rely on the speakers in the HDTV set. After compression, Dolby 5.1 is carried at the TV station and over-the-air on an
encoded bit stream at 384,000 bits/sec.
|
Now it's time to fade to black on the worlds of politics and recent history and TV rules and dark streets with millions of black snowy TVs that now will never be. Instead, now we want to switch over to some High Definition technology and engineering, simple stuff like Pixels and Rows and Lines.→
(First, Rows = Lines; simple stuff this be.)
Each of these "half-frames" (odd, then even) is called a Field. When a 1080i30 HD broadcast reaches your HDTV set, the
first Field, the one with the odd-numbered lines, is not displayed on the screen; it's stored in the HDTV set. Then the
Field with the even-numbered lines arrives; this second field is "woven" together with the first field that we stored in
the set; and voilà, we now have a complete Frame, a complete picture, which is displayed progressively from top to
bottom
On the screen of an HDTV set, there will be anywhere from just under one million square pixels (on "720p" sets) to just over two million square pixels (on "1080p" sets). (Older NTSC analog TV sets have rectangular pixels, not square ones like HDTV sets.)
1080p has the potential for displaying more of the detail in High Definition signals, compared to 720p. This difference in sharp detail is most noticeable→
Otherwise, with quality sets, the difference in detail (or sharpness) between 720p and 1080p often is subtle. Take a "test-drive" before purchasing an HDTV set; 720p is less expensive than 1080p, and no one is broadcasting over-the-air in 1080p. (Blue-ray Discs can display at 1080p, a thing to behold.)
Analog Pixels→ The NTSC analog screens (old) really have no true square pixels that we can use to assign a number for comparison. The analog NTSC sets have a moving "dot", a moving point of light, that creates 262½ lines on the screen's phosphors (some of these lines are beyond the visible screen and are invisible) every 1/60th of a second. Each of these 262½ lines is a Field.
Folks who give you a number for pixels on an analog TV screen are comparing tiny square apples with larger rectangular oranges. But on the old black and white NTSC analog TVs, horizontal scan lines simply cannot be divided into pixels. The pixels on the screen of an HDTV set are more closely spaced and smaller compared to an ordinary, non-HDTV set's screen.
Each pixel on an HDTV receiver really is made up of three "sub-pixels", one red, one green, and one blue. By combining
these three "primary additive" colors in various proportions, a single pixel appears to take on most of the colors that
we can see.
 A BRIEF JOURNEY INTO VISION→ |
Wonder why we said that almost every color that we can see is some additive combination of the "primary additive" colors→ red, green, and blue? DAwn asked Miss Morris, her art teacher in grade 9, why red, green, and blue happened to be “The Primary Colors”. After a few go-rounds with Miss Morris on the subject, DAwn was suspended from school (nothing new for DAwn).
A couple of years later, DAwn asked an undergrad math professor the same question; he muttered something about “Fourier Series”. (Yeah, he was totally out in left field.) An undergrad physics professor said that it was “The basic nature of light”. (Also wrong... plus a suspension from his class for DAwn after she let loose with some uncontrollable Aussie laughter.)
A year or two later at the graduate level, the actual answer finally arrived, when DAwn was tied down and required to take a class or two in human neurophysiology. The true reason that red and green and blue are the primary colors for Humans has nothing on Earth to do with these particular colors, nor with Fourier series, nor with the nature of light, nor with the color of bandicoot fur.
The Answer→
Red, green, and blue are Not The primary colors. Because lights of these three colors can be added together to produce white, they are, by definition, called Primary Colors. But we do need three primary colors to add that will synthesize most of the actual pure spectral colors that we can see. Why?→ Because of the structure and functioning of our eyes. So let's take a peek into our eyes.
There are two interesting types of receptors in the human eye, rods and cones. Rods are great for seeing in very low light, they will respond to a single blue-green photon (they're most sensitive in the blue-green area); unfortunately, at night, the sky does not turn blue-green. So anyway, rods are light sensitive (motion sensitive too, when you connect everything); but rods are not great for "High Definition", especially in low light.
Rods also are missing from the fovea, the center of our visual field where we form sharp images; they are scattered here and there about the retina... and so they're responsible for peripheral vision and night vision. But if all we had were rods... we'd have No use for High Definition TV.
Outdoors at night, the fovea is not sensitive; most of our visual information at night is carried by the rods, especially those in the periphery of our retinas. (When black bear charges out of the dark, we want to see him fast and peripherally; we're not especially concerned about receiving a high definition color image of his fur.)
But it is the cones (ta da) that 1.) carry color information, and 2.) provide higher resolution. Cones are nerve cells in the eye that are tapered, vaguely like a cone. But cones are not very sensitive to light. They're concentrated in the center of the retina, in the fovea, providing high resolution central vision in bright light, in full color.
(An Aside→ Humans have poor night vision. One reason is that we lack a tapetum lucidum ("bright tapestry" in Latin), a layer of tissue in the eyes of many animals, even some other primates, lying behind their retinas. The tapetum reflects light back through the retina and increases the light available to the rods. This improves vision in low-light conditions and contributes to their superior night vision. Ever see an animal by the roadside having very reflective eyes when our car headlights strike them?→ That's the tapetum lucidum.)
Now... humans don't see much color, if any, in the darkness of night; our cones basically just shut down. Cool. So what about red, green, and blue?
OK... Each cone can contain only one of three pigments, a violet-sensitive pigment called cyanolabe, a green-sensitive pigment called chlorolabe, and a yellow sensitive pigment called erythrolabe. When a cone with a particular type of pigment is stimulated, it doesn't have the vaguest idea what color has stimulated it; e.g., a cone with the yellow pigment may have been stimulated by 100 photons of orange or 1,000 photons of red. (Cones have a broad, overlapping range of sensitivity.) It is really the difference between the signals received from all three types of cones that allows our visual system to perceive the ten million or so colors (hues) that we can see.
And surprise, we don't have a visual pigment whose sensitivity peaks at red or (precisely) at blue. But red, green, and blue cover most of the color range that we can see (about 400 nanometers (violet) to 700 nanometers (red) ), and by stimulating our three cone types, just as a true spectral color would, these three "primaries" can create (simulate) most of the natural colors in our visual range. (Most, not all.) And so while All of the colors that we can see in the world cannot be "faked" by adding various amounts of red, green, and blue, when watching color TV, we really don't notice the deficiency. TV displays can mix red, green, and blue pixels to generate what we perceive as a full spectrum of color.
It is these three types of cones that are responsible for the need for three "primary colors", but there is no rule that they must be red, green, and blue. Red, green, and blue can be mixed to produce white; that is the only requirement for primary colors. Normal humans, and most other primates, are trichromats; we require three pure spectral lights mixed together to match all the colors in our visual spectrum... and whatever three these may be are called the "three primary colors".
In Other Words→ It's important to note that the Red + Green + Blue color model is merely a convenient means for representing colors, and it is not based on the types of cones and their pigment sensitivity in the human eye.
(Three pigments is by no means a maximum across all lifeforms. Up to 10% of women and lots of birds are tetrachromats,
with four pigments; we're still not certain what the somewhat tetrachromatic women can see in the way of additional colors,
but many birds can see into the ultraviolet region of the spectrum. And there is a species of shrimp that has 20 different
photoreceptor pigments... and thus requires Twenty primary colors. It is left as an exercise for the reader to
design a compatible B&W/Color TV system suitable for this species of shrimp. (Analog is fine.) )
Once Again Lightly→ OK... Back to HD→ How many rows of pixels are there on an HDTV set's screen? "720p"
tells us there are 720 rows; "1080p" tells us there are 1080 rows. The "p" in 720p and 1080p tells us that each row of
pixels
In the US, HD programs are broadcast over-the-air in one of two ATSC digital formats→ Either 720p or 1080i. 720p has fewer rows of pixels than does 1080i, but it has the advantages of "p"... the advantage of progressive scanning→ 720p is better able to display rapid motion; e.g., a football game. Why? Because in a "p" (progressive) system, the Complete picture is captured by the TV camera at once. Every line is scanned sequentially in the TV camera, from top to bottom. Line 1, line 2, line 3... until the bottom of the picture is reached. And with 720p, 60 complete frames are captured by the camera every second.
The Bottom Line→ Broadcasts at 1080i must blur the picture slightly to prevent "twitter"; twitter (here) is where something appears on a horizontal line in only one of the two fields making up an "i" frame. 1080i transmissions Do have slightly better spatial resolution than 720p broadcasts do. But 720p transmissions have better temporal (motion) resolution.
1080i produces a sharper picture when the image is stationary or moving slowly, because it has more scanning lines.
720p, on the other hand, excels at reproducing rapidly moving objects without blurring, since its full-frame progressive
scanning never chops a frame in two. And 1080p is the best of both worlds→ both good spatial and good
temporal resolution. But ATSC digital cannot broadcast 1080p over the air in the 6 MHz that the miserly FCC has
allowed for digital channels. (6 Mhz, the same for digital channels as for analog channels.) But you can get 1080p
from the newer Blu-ray Discs.
Now it's time to bore deeper into "Video Formats" like 480i and 720p and 1080i and 1080p→
Resolution Confusion→ Few items are used so erroneously by so many folks as video formats are. More people are confused by video formats than are confused by their HDL and LDL cholesterol scores. Over the years, your dog Wolf has learned that when something appears to be as confusing as video formats do, they almost always are very simple in actuality... so don't let the sales folks in Big Box Stores try to confuse you on the subject of video formats... just to sell you a more expensive HDTV set.
First→ Video formats like 720p and 1080i and 1080p are used in two different ways when one is chatting about HD and non-HD broadcasts→
These two uses often are quite different. And Format Codes can apply to both analog and digital broadcasts and to analog and digital TV sets.
We specify the Format Code with which a TV Picture is being transmitted, and the way that a TV Picture is being displayed on our TV receivers, by answering three questions→
Time For an Example→ Let's see what the Format Code is for our good old NTSC analog broadcast system. This is a nice example because, unlike the new digital formats, the old analog TV signal was transmitted and displayed in just one format code; and the picture was always transmitted with the same format that it was displayed on the old TV set's screen.
First→ We know that 480 lines or rows of video are broadcast for each analog picture (or "frame"); so our format code would begin with the number 480 (the resolution).
Second→ To answer the question→ Is each frame interlaced or progressive, we simply ask if all 480 lines are transmitted at one time from the TV camera, top to bottom... 1, 2, 3, ..., 479, 480. Because that is one way to do it, send all 480 lines progressively from top to bottom... send them all at once. If that's how our 480 lines are sent, progressively, then our second value is a "p". "p" stands for "progressive"... and so we'd now have 480p for our Format Code.
But there also is another way that we can send the 480 lines that eventually will make up the picture on our analog TV set; we also can send them "interlaced". Interlaced means that half of the lines (240 lines), every other line, the odd lines, are sent from the TV camera first... 1, 3, 5, 7, ..., 477, 479. And if we don't have a flat-screen TV, those 240 lines are displayed immediately, no storing them. And then, 1/60th of a second later in this example, the even lines generated from scanning the image in the TV camera are transmitted... 2, 4, 6, 8, ..., 478, 480 and displayed immediately. If this is the case, we'd now have 480i for our format code.
It turns out that, to reduce flicker in the old NTSC TV sets when NTSC standards were being developed, the old analog NTSC system sent those 480 lines interlaced... first the odd scanning lines trace across the image in the analog TV cameras; then "black" is transmitted for an instant; and then the even scanning lines from the TV camera trace across the image in an "interlaced" fashion... so we put an "i" after the 480... meaning that frames (complete pictures) are broadcast with 480 lines, but first the odd lines are sent, and then the even lines are sent. We specify 480 lines with "interlaced" transmission and display as 480i.
And Third→ We want to specify how many frames (complete pictures) are sent per second. It's important to understand that "480i" also can be a "family" of resolutions. Each "member" of the family refreshes the whole picture on the screen (the frame) a different number of times per second.
In the US, under the old NTSC analog 480i standard, 30 complete pictures were sent from the TV station to our TV sets each second; i.e., 30 frames per second. And so we now can specify our complete Format Code as 480i30. And if we are sure that there is no room for ambiguity, and that everyone will know that 30 complete frames are being sent and displayed each second, we can use a "short-cut" and simply specify the Format Code in our example as 480i.
Let's pause here for just a moment to go over this, because it's very important. A Format Code written as 480i can mean two different things→
Fast forward now to the present and to HD broadcasts. There are two formats used for HD broadcasts in the US under the new digital ATSC standards. The first is 720p60. (720 lines (rows) are in each complete picture; p = progressive (not interlaced), the whole picture is sent from top to bottom at once; and 60 complete frames (pictures) are sent each second to our HDTV sets.) Because this Format Code 720p60 is so common today, it is often simply written as 720p, and we assume that 60 complete frames will be sent from the TV transmitter to our HDTV set every second.
The second format that is used for HD broadcasts in the US is 1080i30. 1080 rows in each picture;
i = interlaced, the 1080 lines are sent as 540 odd lines and then 540 even lines; and 30 complete frames
are broadcast every second. Because this resolution is also so common today, it is often written simply as 1080i,
and we assume that 30 complete pictures will be sent from the TV transmitter to our HDTV sets every second. ¿Está claro?
Great.
|
Short-Cuts ↓ |
Families ↓ |
| Transmission Formats At The TV Station→ |
720p is short for 720p60 1080i is short for 1080i30 |
Example- Family 720p Has Members- 720p60, and 720p59.94. |
| Display Formats On Your HDTV Set→ |
Example- 480i is short for 480i30 |
Example- Family 1080p Has Members- 1080p60, 1080p120, 1080p240, 1080p30, 1080p29.97, and 1080p24. |
Currently (2009), there are six picture formats that the ATSC Standards have labeled HD; but only two of these six video formats are used in the US for HD over-the-air (or cable or FiOS or satellite) broadcasts→ 1080i30 and 720p60.
All US HDTV sets will work fine receiving either of the two HD formats, 720p or 1080i. ABC sends out its HD programming in 720p (720p60), CBS sends out its broadcasts in 1080i (1080i30), no problems. They both look great on good HDTV sets.
The most common HDTV sets today (1080p, called "full HD") can display 1080p60. 1080p60 is not one of the
standard ATSC 18 video formats, and it is not presently (May 2009) broadcast
(On 1 August 2008, DISH Network Satellite TV made the movie "I Am Legend" available "On Demand" at 1080p. This upgrade in resolution wasn't available for all subscribers, but it was a no-charge addition for anyone who owned an HD DVR capable of playing MPEG-4 video.)
Store Vs Home→ Self-styled "purists" warn that sets never look their best in a store; the lighting is bad, and store employees rarely set them up and adjust them properly. But this is exactly why you should look at them in a store. Most people use their TV’s right out of the box, with all the default settings. So comparing the store displays is a great way to see what is likely the worst for each set. If the set looks good in the store, it should look even better in your home.
A Critical Point→ While HD is only transmitted over-the-air at 720p and 1080i, your HDTV set always will
convert the transmission format to the set's "native" format. Thus, if you are watching HD at 720p on ESPN HD or ABC using
a 1080p HDTV set, your HDTV set will "upconvert"
Also 1080p60 HD video signals are available from the new generation Blu-ray Disc DVD players. But broadcasting
1080p60
Note→ Both analog and digital transmissions in the US are broadcast using 6 MHz (6,000,000 cycles per second) radio frequency channels... e.g., Channel 6 is transmitted using 82 MHz to 88 MHz, whether NTSC analog (color) or ATSC digital (color)... everything is broadcast in color today, even old black and white movies.
The Bottom Line→ Should you buy a 720p or a 1080p→ We'd consider a high quality 720p; it's cheaper, and few folks can see the difference in resolution between the two formats on high-quality sets, until they reach 50". If you have a large screen, or a large projection TV, or Blu-ray Discs; or if you actually believe you can tell the difference in resolution between 720p and 1080p, then spend the extra money and purchase the 1080p. Also, if you are planning to display pictures from your PC on your HDTV, get the 1080p.
Nota Bene→ 1080p, when used to describe HDTV sets, is a short-cut terminology for 1080p60, often called
"Full HD". However, in mid-2009, 1080p is increasingly used to mean 1080p120 (and perhaps even 1080p240).
| FORMAT CODE (SHORT-CUT) |
LINES PER FRAME |
INTERLACED OR PROGRESSIVE |
FRAMES PER SECOND |
BROADCAST OVER-THE- AIR |
| 480i | 480 | Interlaced | 30 | Yes (Analog/ Digital) |
| 720p | 720 | Progressive | 60 | Yes (Digital) |
| 1080i | 1080 | Interlaced | 30 | Yes (Digital) |
| 1080p | 1080 | Progressive | 60, 120 | No |
First→ The Cardinal Rule→ (No, this rule has absolutely nothing to do with the family Cardinalidae of the order Passeriformes.) Our Rule Is→ No matter What The Native Display Format of your HDTV set... 720p or 1080p... your HDTV set will convert any format that it can receive... 480i30 (SD) or 480p30 (ED) or 720p60 (HD) or 1080i30 (HD) or 1080p60 (Full HD), and so on... to its Native display format.
For example, a 720p60 Panasonic HDTV set will convert 480i30 and 480p30 and 720p60 and 1080i30 All to→720p60, which is the native resolution of this HDTV set. How well the HDTV set does this conversion is a major factor in how good the picture on the HDTV set looks; better, generally more expensive sets, do their conversions better. Some lower price "off-brand" HDTV sets can do an Awful job in their conversions; and they look awful. (See "No Free Lunch" theorem.)
But some HDTV sets do the conversion so well that an analog 480i30 broadcast looks better on them than on an analog set (yes, the wider screen and the better optical quality of LCD and plasma flat-screen sets don't hurt either). OK... Now what about 1080p120?
The problem is that liquid crystal molecules take time to change their polarization, as the voltage in each tiny cell
varies; and so with LCD sets, motion blurring is common, especially during fast action scenes such as sporting events. By
displaying an image twice as often as 60 times per second, the liquid crystals respond faster, and motion blur is decreased
on LCD sets. This "motion blur" is not a problem on plasma HDTV sets, and there is no real advantage for plasma sets to
go to 1080p120. Plasma sets have no motion blur and are cheaper than 1080p120 LCD sets.
Example (March 2009, Recession Prices)→
Movies And Judder→
The interest in 1080p120 also has to do with movies...
It's October 1927. Full-length commercial sound movies, "Talkies", have just been introduced. Some standard, some constant speed for the "sound head" must be agreed upon. 24 frames per second is chosen; it's the slowest speed, and thus the cheapest speed, which allows for minimally acceptable sound quality. And so movies are shot at 24 frames per second. And for the last 82 years, movies have been shot at 24 frames/ seconds.
It's now 1941. Let's move over to the parallel track along side Talkies. Television, a dream still mostly in the future. In May of this year, the FCC approves the old analog black and white NTSC TV standards. NTSC TV specifies that pictures will be displayed at 30 frames per second. But it's more complicated than just that→ Film projectors project the entire image at once. But as we explained, the old analog TVs cannot draw all their 525 lines at once without noticeable flicker. So picture tubes draw half the 525 lines per half second. Odd lines are drawn first, followed by even lines in a second field. So with TV, you had 60 fields per second... recall... "interlacing".
Movies = 24/sec; no fields at all. TV=30/sec; two fields, interlaced.
If we are going to show movies on TV (and early TV had a lot of B-movies), some convoluted conversion is needed to make movies viewable on TV. Because 24≠30. To solve the problem, you have to fill in the film frame gaps with "something", some junk. And "filling in the gaps with something" can cause judder. "Judder" is especially noticeable with 1080i30... a jerky-looking phenomenon that's really bothersome when the movie camera pans. Even 1080p60 can have "judder"; 60 is not an even multiple of 24 either.
The solution to 24≠30 is often called 3:2 pulldown (also known as "2:3 pulldown"). 3:2 pulldown is the process used to convert 24 frames per second on film into 30 frames per second interlaced for TV. (It actually converts 24 into 29.97 per second, but that's a whole new tale that we'll be getting to when we look deeper into color TV.) The term "pulldown" refers to the mechanical action of the "pulldown gate" in a device that converts film frames into video frames; the device is called a telecine, and it "pulls down" each film frame into its imaging area. ("Telecine" (television + cinema) is used to refer to both the process of 3:2 pulldown, and the device that does it; it's often simply called "TK".)
This "convoluted conversion" process we referred to, called "3:2 pulldown", shows one movie frame three times and then the next movie frame two times. Although the arithmetic is interesting, it all boils down to repeating some movie frames the right number of times so that they synchronize with the television pictures.
3:2 pulldown telecine works, but it's kind of wasteful. Every time you repeat a movie frame, you are needlessly transmitting data, and data takes up bandwidth. Would it not be better if we sent the data for a movie just once? This is why the new ATSC digital standards allow the transmission of 24 frames per second, as well as copying the old NTSC TV's 30 frames per second. But there are very few digital 24 frame per second transmissions in the US.
Enter the new and more expensive 120 frame per second (120 Hz) HDTV sets. 120 is a very "flexible" number, as DAwn's arithmetic teacher would have phrased it... 120 is an even multiple of 24... 5 × 24 = 120. And so, these new HDTV sets avoid the need for "3:2 pulldown" by changing the TV frame rate to something that's an even multiple of 24. Every frame of film (24) creates five frames that appear on the screen (120); 3:2 pulldown is in effect undone. And so, that's another reason that 120 Hz refresh rates are becoming the norm.
At 60 Hz, you have to display (2, 2, 3, 2, 2, 3...). But at 120 Hz, each frame gets equal weight (5, 5, 5...). However, some folks complain that 120 Hz gives them the feeling they're watching a soap opera, that it takes away the "movie effect". Check it out at a Big Box Store and decide for yourself. It seems to depend on just how the manufacturer of the HDTV set creates the interpolated frames; again, you simply have to check it out.
If movies look "juddery" to you on 1080p60 or on 720p60 HDTV sets, look into 1080p120. Some viewers notice jerky motion when "3:2 pulldown" is used, especially on full scene panning, because the various film frames did not all get equal screen time. If you don't have a problem with judder on 1080p60 or 720p60, your choice may be solved.
(And even at 1080p120, some LCD sets still may have a problem with judder when displaying movies; and
some LCD sets still have a problem with blurry screens during fast motion. And so maybe the refresh rate is not the whole
story. Note→ If you don't like what it's doing to film, you can turn off the 120 Hz feature and revert to 60 Hz.)
CABLE And FiOS And SATELLITE Too?→ If your TV programming comes to you from a cable provider like Comcast; or by a satellite provider like DISH; or even better, by Verizon's "Fiber to The House" FiOS service; or if you watch only closed-circuit TV (like a security camera); or if you hate TV and never watch it... then you may not notice ANY changes in your TV after 12 June 2009.
Then again, you may scratch your head in wonderment when everyone else in your neighborhood is getting up and going
to her window and opening it and sticking her head out and yelling, “My TV is crawling across the floor shouting in
binary, 'Feed Me, I'm Hungry', and I'm mad as hell and I'm not going to take this ATSC Digital anymore.” (Sorry,
think we mixed in one too many allusions there.)
| ITEM | AS OF→ | US TV HOUSEHOLDS (Millions) |
PERCENTAGE OF TV HOUSEHOLDS |
SOURCE OF DATA |
| WORKING TVs | 2009 | 114.5 | 100.0% | Nielsen |
| CABLE TV | December 2001 | 66.7 | 65.2% | US Census (SNL Kagan) |
| CABLE TV | December 2007 | 65.1 | 57.7% | The 2009 Statistical Abstract of the US Census Bureau, from data supplied by SNL Kagan, a division of SNL Financial LC. |
| SATELLITE TV (DirectTV + DISH) |
December 2008 | 31.4 | 27.8% | DISH + DirecTV, 2009 |
| SATELLITE TV And/Or CABLE TV |
December 2008 | 101.5 | 90% | Analysis of Nielsen Data |
| HOMES WITH HD TELEVISION SETS |
January 2009 | 46.8 | 40.9% | Nielsen |
| HOMES WITH HDTV AND HD PROGRAMMING SOURCE |
January 2009 | 31.3 | 27.3% | Nielsen |
ADDITIONAL NOTES→
That having been said, let's dig deeper into CABLE. And then, we may even dig a little deeper into FiOS and satellite... who knows? But first cable→
Cable has more 6 MHz channels and thus more bandwidth than than "over-the-air" TV ("over-the-air" means received with your TV antenna). Cable has been assigned 125 channels (plus 7 "reverse" channels for communication FROM the subscriber) by the FCC; and DIGITAL CABLE can compress many programs onto a single physical cable channel.
Digital cable can accomodate anywhere from two High Definition (720p or 1080i) "virtual channels" (programs) in one physical cable channel, or up to perhaps a dozen Standard Definition (480i30) "virtual channels" in one physical cable channel; this can work out to a total of hundreds of "virtual channels" on a digital cable system.
Over-the-air, you'll receive perhaps 10 ATSC digital channels, with 1-2 programs per channel; this comes out to about 15 digital programs over-the-air, and digital cable, with 10-20 times as many programs, easily wins the programming battle. (Of course, more is not always better.)
But the compression employed by digital cable comes at a price; some cable channels look awful, often due to over-compression; some programs are filled with pixelation (which also shuts off the sound). ATSC digital over-the-air broadcasts and FiOS have better picture quality than much of cable, especially if the ATSC digital over-the-air station is broadcasting just 1-2 programs on its assigned physical channel. And FiOS does not compress any of its more than 100 HD channels. (This is a good thing.)
As of July 2008 there were HD broadcasts, over 25% of the day, on...
So in July 2008... satellite won the battle of "Who had the most HD". (A similar competition raged in 1966-1967 over color broadcasts, although things were almost strictly over the air back then; NBC coined the slogan, "94% color after dark." By the early 1970's, virtually all network broadcasting was color.)
Important→ Few channels in the above HD count are broadcasting in HD 100% of the time.
Also Important→ How many and which HD channels you receive depends on your particular cable or satellite or FiOS "package"; and there are MANY different "packages" at different prices.
Slightly Important→ As of April 2009, in our area of northern Maryland→
HD Update→ Most HD Channels= FiOS; Second Place= DirecTV; Third= Cable.
10 February 2009→ Verizon's FiOS TV is challenging DirecTV as the provider with the most HD channels, according to a study from market researcher Pike & Fischer. The study says that as of January 2009, DirecTV offered 104 HD channels, and Verizon's FiOS had 103 HD channels. DirecTV had established itself as the leading provider of HD channels; but Verizon has boosted its HD lineup in several cities and now offers more than 100 HD channels in every market that it serves.
The Pike & Fischer study says Comcast has “one of the smallest selections of HD channels”, offering fewer than 40 HD channels in some markets. (Comcast has recently increased that number in several markets.) “Cable networks do not have the capacity of Verizon's Fiber To the Premises (FTTP) infrastructure nor of DirecTV's satellite coverage and thus faces constraints on HD channels.”
Although FiOS and DirecTV may offer more HD channels than cable, P&F notes that Cablevision and Time Warner are among a
group of cable providers that offer “a substantial number of HD channels for free... But it is important to look at
what content is actually being offered, and at what price.”
First some basics of Cable Systems→
There are two types of cable TV, the original analog, and the newer digital→
Thus, over-the-air channel six begins at 82.0 MHz. But the standard for analog cable channel six begins at 83.25 MHz.
With analog cable, if you don't have a "cable ready" TV set, you can get a tuning box from your cable subscriber; generally, the analog cable box converts the cable frequencies to broadcast channel 2, 3, or 4 (whichever is unused in your area). You connect the box to your TV set's antenna screws (or coaxial cable input), and set the box to the cable channel that you want to receive.
Digital cable is QAM modulated ("Quadrature Amplitude Modulated") at the head end, either 256-QAM or 64-QAM (more on QAM coming up). QAM is the modulation format by which digital cable channels are encoded and transmitted over fiber-optic and coaxial metal cable.
QAM tuners are analagous to ATSC tuners, which are required to receive over-the-air (OTA) digital broadcasts by local TV stations; and many new "digital cable ready" HDTV sets have tuners for both ATSC (OTA) and QAM (digital cable). A TV with a QAM tuner demodulates (and decodes) digital cable without the need for renting a set-top box from the cable provider; such a box usually has one or two QAM receivers (tuners), along with decoders for channels that are not broadcast by cable "in the clear". (Cable programs that are sent from the Head End "in the clear" refers to programs that are Not encoded. Usually an entire digital cable channel is either "in the clear" or not.)
QAM can carry nearly twice the number of bits/second as over-the-air ATSC 8-VSB modulation; but since QAM requires a cleaner signal path (a path with fewer potential errors), it is a good match for digital cable.
NOW... According to the National Cable & Telecommunications Association (NCTA), as of March 2008 there were 27 million households receiving analog cable; HD is sent over only digital cable. If you are one of these 27 million subscribers who have totally analog cable, you cannot receive any HD from your analog cable. None. Never.
Cable programming begins at what's called the HEAD END. The HEAD END is the location where the cable system accumulates ITS programming... from satellites, through microwave towers, from local broadcasts over-the-air, from its own studios, from local broadcasts over fiber-optic cable, from Neptune, you name it. There are about 8,000 HEAD ENDs in the US.
The HEAD END first assigns a "virtual" channel to each program that it makes available to the community. The HEAD END then "shoves" each program onto fiber optic (or coaxial) "trunk cables", which carry the programming to each neighborhood that is serviced by this cable provider.
Today, the majority of digital cable programming is ENCRYPTED at the HEAD END, especially "premium" channels
like Showtime. (You have to pay to play. And to play, you have to have the proper "key" to decode the encryption.)
As you may have deduced by now, there are three varieties of cable systems→
§ § § § § § § § § § § §
AND you can always put an antenna on your roof; the HD quality is often superior to digital cable (because there is no additional compression after an HD program leaves the TV station); you will get high quality HD transmissions, perhaps close to FiOS in video quality, if you have a good roof-top antenna that's properly aimed and not too far from the antenna tower; you just won't get all the "non-BROADCAST" cable channels like A&E-HD and ESPN-HD and SciFi-HD and Discovery HD.
Another interesting thing about analog cable is that one program (like the TV Guide Channel) totally fills one
Finally, analog cable is susceptible to interference. So in summary, no HD, one program per 6 MHz physical
cable channel, and possible interference.
Typical Allocation Of A 750 MHz Hybrid Cable System |
Since Digital Cable is, well, digital, and digital things can be represented by bit strings, we would expect to be able to measure the capacity of digital cable in bits per second. Digital cable, using 256-QAM modulation in a 6 MHz physical RF channel, can carry up to 38.4 million bits per second. This, however, represents potent compression by the cable provider; this is nearly double the maximum bit rate that an over-the-air TV station can broadcast (19.39 Mb/s).
HINT→ The more digital cable compresses a cable program, the worse it will look. TV compression is definitely a lossy process. (A digital process is called "lossy" if, when it comes time to reverse it, you don't end up with all the information that you started with originally; this "loss" of information can be subtle, or it can be a major degradation that makes watching a TV program nearly impossible.)
Digital cable is touted as providing a higher quality picture than analog cable. This is true, with a dramatic improvement in color resolution (called "the chroma resolution"). Since the human visual systems doesn't see color details very well, we can cheat a little and throw away a lot of color data without anyone noticing, both in NTSC analog color TV and in ATSC digital color TV.
Analog NTSC TV shows only about 120 of its 480 lines of a frame in color; digital cable (and ATSC digital) shows about 270 of its lines with color. But again→ Digital compression "softens" (there's a euphemism) the quality of a picture, particularly on digital cable channels that are severely compressed. (See "No Free Lunch" Theorem.) We'll dig into the whole subject of color TV in just a bit.
So in summary, Digital cable can transmit HD, it can carry a high bit rate, it can be tightly compressed, too much compression looks bad, and there is more color detail with digital (both ATSC over-the-air and cable).
A CRITICAL POINT→ If your cable provider does not offer digital cable, you WILL NOT receive any HD programs (in HD) via cable. So if the FCC has counted correctly, and there are 20-40 million households that presently have analog cable, these households will not be able to receive programs in High Definition.
And if your cable provider offers Both analog and digital (hybrid), but you don't subscribe to digital cable, you will not receive HD programs which the cable company has encoded; if your HDTV set has a built-in QAM Tuner, as most newer sets do, you Will be able to receive Some HD via digital cable at no cost, usually the HD programming which is locally broadcast and is not encoded... like Letterman on CBS, carried by your local CBS affiliate station in HD.
HUH?→
OK... All HDTV sets have ATSC tuners (so they can receive digital signals over-the-air); some HDTV sets also have QAM tuners. Back when all TVs were analog, the "Cable Ready" TVs didn't need QAM tuners; that's why you just plugged the cable into the back of the TV and tuned in the 6 MHz analog cable channel of interest... no QAM receivers (tuners) or set-top boxes were required. Same for the current HDTV sets with QAM tuners... just plug your cable into the back of the set and receive un-encoded digital cable.
Now... TV manufacturers usually don't discuss it, and they rarely print anything in their instruction manuals about it... but cable providers relay to any customer whose set has a QAM tuner all digital (including HD) transmissions that are not encrypted. So if your QAM tuner is on an HDTV set, you'll get some HD free. No set-top boxes are required. How can this miracle occur?
If cable providers broadcast local programming, then they also must carry broadcasts of High Definition digital local programming, unencrypted ("in the clear"), that does not require their customers to use rented equipment, per FCC Sec. 76.630 and CFR Title 47, §76.901(a). Cable providers comply with this law by broadcasting HD over QAM channels. (The law does not require cable providers to advertise the availability of HD, and cable representatives occasionally will insist that a converter box is needed to view any HD channels.)
The cable channel numbers seen on your digital cable set-top box and in your program guide are VIRTUAL numbers.
In the old days of 2-digit analog cable channels, the channel you were viewing actually corresponded to an "RF channel".
When you went to channel 75, your cable-ready TV or set-top box was actually tuning to the radio frequency for cable
channel number 75
But with the advent of digital cable, and hundreds of three digit channels, that all went out the window. Now the cable company can stuff a dozen "services" into a single cable RF channel. These services basically pile up in that channel, and now your set-top box and/or new HDTV set pulls them apart into individual programs.
The virtual numbering plan in the digital cable system is proprietary, and requires the set-top box to decode. So they may have one or more services at RF channel 11. But HDTVs with QAM tuners don't know about virtual service numbers, they just knows that they found it at RF channel 11. So the TV set gives it service number "11-0", and if it finds any others piled up there at RF channel 11, it'll call those 11-1, 11-2, etc. After all, HDTVs are expecting to find digital multicasting within a 6 MHz RF channel anyway; they are trained to sniff around, looking for multiple programs (services) in one physical RF channel.
Many cable companies shift their line-ups frequently, so that QAM-sters must rescan to find the new arrangement. But it's not uncommon to find 9 or 10 free HD channels, though you may find one on channel 81-11 (the 12th "service" on major cable channel 81, for example). And you are not required to pay extra. But if you want a non-broadcast HD channel (like Discovery HD) which is almost always encoded, then you will need a set-top box (or at least a "CableCARD").
In Other Words→ A QAM tuner integrated into your HDTV set allows the free reception of unscrambled digital programming sent out by cable providers, usually local broadcast stations; however, most digital channels are scrambled, because the providers consider them to be extra-cost options and not part of the "basic cable" package.
The CableCARD→ Since July 2007, the FCC has required cable providers to separate security hardware (and software) in their set-top boxes from the hardware (and software) that does the receiving and tuning and recording. All of the security issues (the part that makes you pay $$$ each month or you get nada) are now on a card that slips into the box (or into the back of your TV)... the "CableCARD".
The FCC is working on the premise that you can buy the box (or buy a TV that incorporates the box), take it with you if
you move, and just get a new card from your new cable company; the card is about the size of a credit card (but a bit more
chunky). Comcast currently does not charge for the first CableCARD in most markets, but they require that their technician
install the card in your TV.
BE CAREFUL WITH "DIGITAL" CABLE→ "Digital", as applied to cable systems, can be slightly confusing; so your dog Wolf is now going to make it simpler and less confusing. Let's follow a TV transmission from the TV broadcast antenna, to the cable provider, to your home...
OK... cable often carries stuff that is not broadcast over-the-air, like HBO and CNN and the Sci-Fi channel.
Cable also carries programming that IS broadcast over-the-air in your regional area.
NOW... During the transition from analog to digital TV, most over-the-air TV stations have TWO TV transmitters; each broadcasts on its own separate channel. One is transmitting in the old NTSC analog format, and the other is transmitting in the new ATSC digital format (which is the standard for over-the-air digital in the US). In theory, this will allow working out some of the bugs in the new ATSC digital transmission.
Your local cable company receives both transmissions, the old NTSC analog (at the latest, until
Example in our area→ Virtual channel 211 (WBAL-DT) and virtual channel 208 (WBAL Insta-Weather) are stuffed along with the TV Guide channel into physical RF cable channel 11.
This answers the question of why Comcast bothers to convert everything to "Cable Digital" before sending it out on its
cable network. Answer→ Digital technology enables Comcast to "compress" its signals. Because programs take up
less space in "cable digital", more programs can fit through the existing infrastructure using compressed "Cable Digital".
Each TV station in the US broadcasts within a piece of electromagnetic spectrum that is 6 MHz (6,000,000 Hertz) wide. For debugging digital television broadcasting, the FCC gave most stations an additional 6 MHz, usually in the UHF band (channels 14-69), free. Thus, each television broadcaster had 12 MHz of spectrum space (for about 10 years).
HD guru Bill Husted of the Atlantic Journal Constitution points out that the HD picture is sharper when it is
received over-the-air by an antenna at your home. Cable and satellite providers compress the HD picture, so that they can
offer more channels; hence, while over-the-air broadcasts can fit a maximum of
Yes, over-the-air TV stations compress digital broadcasts before transmission; but the compression by cable and
satellite providers is on top of this. Of course, there is no reason why you cannot install a rooftop antenna
to receive regional TV broadcasts (a few of which are usually network affiliates) for
But folks who still receive TV over-the-air are generally less affluent. These are not in general consumers who will invest in digital sets. Or will they? With the advent of mobile and handheld digital in 2009 (ATSC-M/H), might over-the-air digital broadcasting reach a new audience? Stay tuned.
Important To Note→ Cable providers compress different channels carrying HD by different degrees, for reasons that change with the phase of the moon. Just bear in mind that the more an HD broadcast is compressed, the worse it will look. And the same goes for Standard Definition (SD) cable programs.
In some situations, the compression becomes so severe that the cable channel shows no image (black) or just digital
static (usually pixelation). Pixelation usually kills the sound too. Over-the-air ATSC digital is many bugs with many
patches attempting to fix them. Under perfect conditions, digital can look great; under normal conditions, usually
over-compression or insufficient signal strength, digital often can be unwatchable (and unlistenable).
FOR THE TECHNICIAN→ Using 8-VSB modulation for digital TV, as the ATSC digital standards require for US over-the-air broadcasts, we can broadcast 19.39 MBits/sec of video and sound and miscellaneous data. But if we feed 19.39 MBits/sec into the "exciter" (error correction, modulator, and associated functions), then as a result of the overhead added because of forward error correction and pilot and sync insertion, the actual data rate goes from 19.39 Mbits/sec at the input of the exciter to over 32 Mbits/sec at the output of the trellis coder (a component of the exciter that provides additional forward error correction using a convolutional code). 8-VSB modulation, using Nyquist filtering, can transmit this 32+ MBits/sec stream in a channel width slightly less than 6 MHz. Mirable dictu. ATSC digital broadcasts need every bit of error correction possible; and then more.
The Nyquist filtering that squeezes the entire digital signal into 6 MHz creates a great deal of noise and many errors; that 6 MHz channel width that haunted us in NTSC analog TV (old) returns again to make a great many problems for ATSC digital TV (new). ATSC digital should have been broadcast in 8 MHz channels; but then, the FCC couldn't auction to the phone companies 14 channels located between present TV channels 52-67.
Here in Baltimore County, Maryland, if you pay your cable bill (and if Comcast posts your monthly check to the correct
account), you get local station WJZ's analog broadcast on Comcast cable virtual channel 23 (until 12 June). And you
also can get WJZ's digital broadcast on Comcast cable virtual channel 212, which is sometimes an HD program (if you pay
$6.50/mo extra for HD) . On
A BRIEF ANECDOTE→ We recently visited our aunt and uncle, who had plunked down $7,000+ for two large, beautiful Samsung HDTVs plus installation. "Look at our HD" our aunt said on our arrival, pointing to what was perhaps the worst picture we have ever seen on a flat screen set. Why?→ First, she was tuned to cable channel 21 (WBAL-TV analog) instead of channel 211 (WBAL-TV digital). Next, the installers had forced the picture to fill the width of the HDTVs, resulting in "fat round-face syndrome". Next, we noticed that Comcast was renting our relatives two DVRs (Digital Recorders) with NO HDMI outputs (more on HDMI coming up). The installation (by either Best Buy or Comcast, we were afraid to ask) featured a single, low quality coaxial cable, barely suitable for analog, connecting the Samsung HDTV sets to the Comcast DVRs.
We removed the single, cheap coax (which was causing "ghosting" and which CANNOT carry HD), replacing it with three "component" cables, and we tuned one HDTV set to "Discovery Channel HD". Voilà, HD. The difference, including the proper aspect ratio (16:9), the elimination of weird static and ghosting, etc, was beyond striking. Our aunt could not believe the beautiful colors and sharp resolution (pictures of bison at Yellowstone). End of anecdote.♣
Just A Note→ The Comcast DVR is digital; the three cables are analog; the HDTV is of course digital. So we
were going from digital to analog to digital. Had we had a DVR with HDMI outputs, we could have stayed digital the whole
way; no conversions. (The scene when our aunt confronts Comcast demanding a DVR with HDMI outputs will not be a pleasant
one.)
Component Video Jacks On HDTV
 |
Back to Comcast→ Since the signals that we get from Comcast are sent to our homes in "cable digital", they must first go through a "set-top box" or a DVR, which is rented from Comcast, for decoding any scrambled cable digital channels.
Anyway, when we select some cable channel on the Comcast set-top box, the box converts "CABLE DIGITAL" into either→
(Hint→ As we said, instead of the set-top box you can use a "Digital Video Recorder" rented from Comcast for a few more dollars each month to decode digital programs. A DVR also can do some neat tricks, like recording two programs at once, or pausing a live broadcast, or backspacing a live broadcast.)
SO... If you have an OLD ANALOG TV, the set-top box will convert "CABLE DIGITAL" to ANALOG, and you can then watch most cable channels on your analog TV. You can even watch some programs on your analog TV set that are broadcast in ATSC digital (but not HD, for that you have to pay extra).
Just keep the "DIGITALS" straight in your mind→
(For The Technician→ "Cable Digital" is simply TV signals that have been modulated by the digital QAM technique, usually digital 256-QAM (but sometimes 64-QAM). See now why a cable-ready TV with a QAM tuner can display any digital cable channel that is not encrypted?
Digital Cable = QAM Modulation→ QAM Tuner. More on QAM coming up.)
In September 2007, the FCC ruled that analog cable systems (generally the smaller cable providers), should not penalize their customers who had only analog TVs after analog broadcasting ceased. And so, the FCC ruled that analog cable systems must not only carry the new digital broadcasts from local and regional TV stations, they also must convert these broadcasts to analog for their customers with only analog TVs... until at least 2012.
Worth Noting I→ A lot of stuff on cable (and satellite) doesn't even come from broadcast TV stations... HBO, A&E, the Weather Channel, the Golf Channel, The Aardvark Channel, etc, are not broadcast over-the-air. These programs are not required to be provided in analog format by analog cable systems.
Now, as we know, digital TV stations, if they choose, can "multicast"... that is, digital stations can broadcast more than one program simultaneously... The FCC ruled that any local analog cable systems need carry and convert to analog only one program from each local station; i.e., an analog cable system would be required to carry and convert to analog only one of the several programs that a digital station was multicasting. In general, the TV station would decide which of its multicast programs (if it's multicasting) the local cable provider(s) would be required to carry.
The FCC also ruled that 100% digital cable providers ("The Big Guys") could continue providing set-top boxes to allow analog TV sets (old) to receive ATSC digital broadcasts from local and regional stations. These digital cable providers did not have to convert any programming to analog. Upon converting to digital cable systems, some cable companies have provided the digital decoder boxes free; of course, most have not.
Worth Noting II→ In September 2007, the FCC also mandated that cable operators could not degrade
over-the-air broadcasters' High Definition signals when they were broadcast over digital cable systems, so that
they looked worse than any other of the cable system's HD. (Yes, the FCC actually had to mandate this.)
NOW→ The conversion spots on cable TV are telling folks that, as of mid-June 2009, there's no need to worry about the transition to digital-only, if you have cable. But the truth about how the conversion will affect cable subscribers has been been scant. What hasn't been very widely publicized is that the conversion to over-the-air digital-only also will affect some cable subscribers.
As we said earlier, at the end of 2007 there were about 65 million US households subscribing to cable. About 38 million of these were digital cable subscribers, meaning they most likely rented a set-top decoder box (or a Digital Video Recorder) for each of their TV sets. These cable customers will not be affected by the transition to digital-only over-the-air broadcasting finalizing in mid-June, regardless of what kind of television sets they may own.
But the 27 million cable subscribers who are receiving analog cable service may have some cause for pause.
You see, June's conversion to digital-only broadcasting gives cable providers two options for dealing with their customers who have old analog TVs. They either can convert the digital broadcast signals to analog at their "Head End" before shoving the programs out onto their network; or they can convert their cable system to 100% Digital and rent customers a set-top box for every TV they have→ A set-top box will convert the digital cable signal to analog, for viewing on older analog TVs. (The $40 subsidized converter boxes won't help here... they are intended for converting over-the-air broadcasts to analog for non-cable over-the-air households, not for unscrambling digital cable for analog sets.)
Folks with "cable ready" (256-QAM) digital TVs don't need to rent digital boxes from the cable company, but then they will only be able to receive local broadcast programming ("basic cable"); and video on demand and the TV Guide also require a digital box.
Now... the big cable companies, like Comcast (the largest) and Time-Warner, are expected to take option #1... that is, they will pump both digital and analog signals through their systems. “There won't be changes in prices because the broadcast stations are going digital-only, ” said Comcast spokeswoman Sena Fitzmaurice. “But there may be changes in prices and services for other reasons.”
Cable companies may convert some programming from analog cable to digital cable, as they already have been doing; but the FCC's rules require that local broadcast channels remain viewable to analog customers. Yet, over time, a complete migration of cable systems from analog to digital cable is inevitable.
WHY?→
An analog signal takes up more space on the cable network than a digital signal does, and subscribers pay less for it. And with digital cable, cable companies also can offer additional services, like "Video On Demand".
BUT→ Smaller cable systems are having a more difficult time. Jess King of Cablevision of Marion County LLC recently spoke to a gathering of residents at an "over-55" retirement community. “My decision was, whether I continued to try to muddle along here with all of my channel space being used up by a few analog channels, or whether I would go all digital,” King said. “So I got an FCC variance to go all digital.”
Now... King's company is small, he says, with fewer than 10,000 subscribers; and he is facing increasingly intense competition from satellite companies that can offer large packages of HD channels, an option not available to him. Whether other cable companies like King's can pass on the costs related to the digital-only transition to customers is a subject that both the cable industry and the Bush Administration's FCC avoided.
The FCC's digital transition Web site says that if a cable company goes all digital, and thus requires customers to begin renting a set-top digital decoder box for every analog TV they watch, “Any costs related to it will be determined by the cable company.” Yet the FCC regulations that were approved in the autumn of 2007 appear to contradict this point.
The FCC's rules require cable companies to provide local broadcast channels to customers with older analog TVs through
February of 2012. (Certain smaller cable systems can request a waiver.) The FCC's rules also note that a cable provider
who converts to 100% digital cable must supply analog customers with the equipment needed to view the local broadcast
channels; and
If that were the case, Jess King (of Marion County LLC) said it would bankrupt him. “I can't put that much money into these homes,” he said. ”How can anyone... I'm talking about the government or even an individual... think that a company could absorb that kind of a cost?”
BUT→ Nothing in the FCC's rules would prevent operators from continuing to offer both analog and digital signals, however.
Brian Dietz, a spokesman for the National Cable and Telecommunications Association, said his organization interprets the rules to mean cable companies are prevented from recovering costs stemming from the head-end down-conversion of digital to analog, not the costs of set-top boxes required by the 100% digital cable option. (Is that what the FCC said?) But fine print aside, analog cable customers just want to know if the digital-only transition is going to cost them more money. And that, according to Dietz, is “a decision that's left up to individual cable operators”. (Is that what the FCC said?)
The Next To Bottom Line→ There is nothing that cable subscribers need to do to continue receiving programs over cable after the June 2009 conversion; but they may be paying more to do it. Cable channels that were previously analog, like the Travel Channel on cable channel 10, are being moved by some cable companies up to channel 110... into the "digital tier", requiring customers to rent digital decoder boxes to unscramble channel 110. And so, some cable customers, lost in the confusion over the conversion to digital-only... a conversion that affects only over-the-air antenna viewers, are ending up paying more to have digital cable service. Watching the same channels, but paying more money for them.
Cable companies have been assuring us that we won't be affected by the conversion to digital-only in June. But several dollars more per TV per month to rent digital decoder cable boxes is an effect... especially when you're watching the same old channels. And if your cable company hands you the line that the channel changes are necessary for the upcoming conversion to digital... “a conversion mandated by Congress and beyond our control”... it's time to notify your state's attorney general and scream "fraud". The digital-only conversion has nothing to do with where cable channels reside or whether or not they are in a digital tier, and the digital-only conversion has nothing to do with paying $5/set/month for a digital cable decoder box.
Comcast's Web Site for Channel Changes stated→ “These channel changes are not related to the federally-mandated Digital Broadcast Transition, which is currently underway and will be completed by June 12, 2009.”
The Bottom Line→
Clarification→ Digital Cable and Digital Satellite do not mean that all programs are received by subscribers in High Definition. Some may be, others may not. On DirecTV (satellite), The Food Network on channel 231 is broadcast to Earth by Digital Satellite, but it's never HD. The Food Network on DirecTV channel 231-1 is also sent by Digital Satellite, but it is often HD.
Caution→ If you buy an "all-in-one" remote control box (for several hundred dollars), and you have
satellite, be certain that it has a hyphen button on it, since DirectTV has been naming some of its channels using hyphens.
Satellite TV is more correctly called Direct Broadcast Satellite or DBS. Since the 1990's, satellite broadcasting has been digital (and compressed), allowing more channels per space satellite. Digital satellite also has given satellite reception a better picture and better sound, with less snow and crackle, as was common with the older analog satellite broadcasts.
By 2008, satellite television from outer space to the satellite dishes that decorate tens of millions of US homes (DirecTV, December 2008 = 17.6 million subscribers (Reuters); DISH, December 2008 = 13.7 million (Multichannel News) is 100% digital, making things simpler to follow (compared to cable, which comes in three flavors→ analog, hybrid, and digital). But like Cable Digital, Satellite Digital also is different from the ATSC digital over-the-air that is broadcast from TV antennas atop towers across the land.
ATSC over-the-air Digital ≠ Cable Digital ≠ Satellite Digital (They're all different.)
Because High Definition broadcasts from satellites to our terrestrial dishes require more "bandwidth" on the satellite broadcast spectrum than non-HD broadcasts, satellite providers are compressing HD transmissions more and more, now using a newer technology than the MPEG-2 compression specified by ATSC for over-the-air broadcasts (and used by many cable providers). The newer technology is called MPEG-4. And MPEG-4 must be decoded using new set-top boxes, such as the "H-20". (No, not water... just thinking how the "Set-Top Box" industry must be the one remaining support for the world's shaky economy.)
In addition, to handle HD, DirecTV is employing a newer transmission protocol called DVB-S2 from the SPACEWAY-1 and SPACEWAY-2 satellites. This allows DirecTV to squeeze more HD programming into its satellite signals than previously was feasible using the older "DSS" transmission protocol.
As of October 2007, DirecTV was still planning to offer as many as 100 national HD channels by the end of the year, all of which were expected to be MPEG-4 compressed. (They came close; by January 2008, DirecTV had over 85 HD channels available.) In fact, as of September 2007, DirecTV was already rolling out MPEG-4 HD boxes, as were several cable operators, who also were anxious to switch to MPEG-4 to make better use of currently available bandwidth.
NOTE→ According to the FCC's "High Definition Must Carry" provision, after the digital-only TV transition is completed in mid-June, satellite TV operators have until 2013 (about four years) to carry local TV stations' HD programming in High Definition. But if a satellite operator chooses to carry one local station's programming in HD in a given market, they must carry all local stations' HD signals, in order to prevent "cherry-picking" the more popular channels.
DirecTV→ DirecTV Direct Broadcast Satellite (DBS) service transmits HD video in a format that is not one of
the 18 ATSC video standards. It is a combination of ATSC 720p60 and 1080i30 formats. The ATSC standard specifies 1920
pixels per line for 1080i30, but DirecTV reduces this number by 1/3 and broadcasts
However, the ATSC format standards were developed for over-the-air TV broadcasts; these standards do NOT apply to satellite broadcasts, especially since the vast majority of satellite programming is "non-broadcast" fare, such as HBO HD, The Sci-Fi Channel HD, etc.
The practice of reducing the original resolution of an HD signal between the broadcast facility and the home is called down-sampling. Thus far, customers have reported down-sampling only on 1080i30; 1920 pixels per row × 1080 rows, interlaced, can be down-sampled to 1440 pixels per row × 1080 rows, interlaced; or it can be down-sampled further to 1280 pixels per row × 1080 rows, interlaced (as in the case of DirecTV), with a corresponding reduction in bandwidth consumption. In contrast, over-the-air ATSC broadcasts of 1080i30 are fixed at 1920 pixels per row × 1080 rows, and no down-sampling is permitted by ATSC standards (which also are the FCC's rules).
Moral→ If you're an HD purist, you may want to view local HD broadcasts using a rooftop antenna; in this configuration, no down-sampling is possible. Nor is additional compression possible that can degrade the picture.
We believe that the quality of the HDTV set, the quality of the cables carrying the programming from the satellite box into the HDTV set, and the quality of the original broadcast are more relevant to the final picture quality of satellite than 1920 vs 1440 vs 1280 pixels per row.
Satellite subscribers may need to upgrade their dishes for HD; usually slightly larger dishes are required for receiving HD. You will need to contact your satellite provider and ask for an HD set-top box (though your HDTV set may have built-in satellite HD reception capability (unlikely) ); and while you're on the phone with them, you may want to sign up for an HD subscription plan as well, giving you extra goodies like CNN in HD.
The Rain Issue→ Due to rain and other forms of inclement weather (e.g., hail), according to DirecTV you will receive a satellite signal 99.9% of the time, meaning that you will not have a satellite signal on average 1½ minutes per day due to inclement weather. However, you should have a higher degree of customer satisfaction with satellite than with cable, according to consumer surveys.
The Bottom Line→ To access HD via DirecTV, you need to pay an additional $10/month HD Access Fee. You
will need a DirecTV Slimline Dish. You will need an HD Receiver such as the "H20". There is a $5 Lease
Fee for additional HD receivers after the first. And there's a Handling and Delivery Fee of $20. Other than
that (and purchasing an HDTV set), you're good to go.
In 2005, WiFi and Internet access became faster, courtesy of Verizon, the "Phone Company" for millions in the US.
The secret was FiOS, which stands for Fiber-Optic Service. (A little thought will reveal why Verizon didn't name it "FOS".) Verizon also has pointed out that in Irish, "fios" means "knowledge". In 2005, in some parts of the US, Verizon's FiOS Internet service was providing 15 million bits per second Internet download speed (and 2 million bits per second upload speed), vs 6 million bps (and 0.384 million bps) large cable companies like Comcast were providing.
Unlike cable, FiOS was a "Fiber To The Premises" (FTTP) service.
In 2005, FiOS Internet was available to about 3 million US homes. Said Verizon, “Verizon FiOS is the latest in fiber-optic technology. It delivers laser-generated pulses of light, riding on hair-thin strands of glass fibers, all the way to your front door. When FiOS meets your HDTV, you'll get TV at blazing-fast speeds.” Verizon was planning to use FiOS to bring all-digital television (with tons of HD) directly into homes.
In Other Words→ With FiOS, stuff was not just carried to (and from) your neighborhood via fiber, as with ordinary cable. In the FiOS world, the fiber actually reached your home; this was the key to the speed and bandwidth of FiOS.
By late 2006, Verizon predicted that, after it does its tweaking, you'll have 100 million bits per second flowing to (and from) your home on fiber. That's three times the THEORETICAL limit of cable. And it's fast enough to let you download entire movies to your home in a few seconds.
In Other Words→ FiOS can run much faster than cable or satellite. FiOS is fast enough to bring just about anything into (or out of) your home, stuff that you'll want for the Network of The Future. And the bandwidth of FiOS is such that compression is not needed for HD. Every premium channel is available on FiOS in HD without "lossy" compression.
When you subscribe to FiOS TV, you abandon cable. FiOS HD is not compressed; no "lossy" compression. It's HD television picture is superior to both cable and satellite. In early 2008, Verizon was giving away a small HDTV set with a FiOS subscription; they told us that they wanted folks to see just what FiOS HD looked like.
A representative from Verizon claimed→ “Our Standard Definition TV is better than their High
Definition.” -Quoted from the W$J, February 2008.
Some FiOS Problems→
FiOS allows Verizon to deliver hundreds of channels of TV (including lots of HD), just like Comcast has been doing, but without the need for compression that degrades the picture. FiOS IS FAR FASTER than cable; "ON DEMAND" takes perhaps three seconds to kick in with FiOS; cable takes quite a bit longer than that. And the FiOS TV picture is clearer and brighter and more consistent than cable, according to folks who have tried FiOS.
Verizon also has introduced a digital video recorder (DVR) that can show its stuff on ALL The TVs in your home... not just the TV that the DVR box is sitting on. You even can transfer pictures and music from your PC to your TV using FiOS.
By early 2008, over one million Comcast customers had switched over to FiOS; to appease stockholders, Comcast again began paying a dividend (something it hadn't done since 1999), and it began a $7 billion stock buyback. These measures were intended to put a bottom under the price of Comcast stock.
The Bottom Line→ In our opinion, compared to DirecTV and Dish Network (Digital Satellite), and to cable providers such as Comcast, FiOS TV provides better picture quality. FiOS should continue to provide more selection, whereas satellite providers may have maxed out their bandwidth capacity. In fact, the satellite providers (along with many cable providers) have increased compression from MPEG-2 to MPEG-4. In order to provide more channels, they have no choice but to increase compression, which results in reduced picture quality.
FiOS is dissected in much greater technical detail below. As of December 2008, Verizon's FiOS TV had 1.9 million subscribers. And by early 2009, it's estimated that 2.0 million former cable households were getting their HD programming from FiOS. By March 2009, FiOS offered over 100 channels in uncompressed HD, including every channel of premium services such as HBO and Showtime and Starz. Stay tuned.
As a result, you may need to add a new rooftop antenna... UHF or VHF or both. This Web site→ http://www.antennaweb.org may be helpful in selecting and orienting your antenna.
Senator Bernard Sanders (IND-VT) sent the FCC a letter asking them to begin (not to intensify, but "begin") an education campaign to alert consumers of this new additional potential expense. He suggested picking up the expense so that Americans won't be forced to pay for cable, satellite, or FiOS just so that they can receive local over-the-air TV channels.
Hint→ Broadcast stations need to consider building analog (it is legal) translator stations to fill in the gaps left by digital; these would be low-power analog stations, and thus they would not place an inordinate burden on the broadcast station.
Yes, digital looks better than analog... when things are perfect. If you are using a roof-top antenna, be prepared for a new, more expensive antenna, installed by a profesional, especially if you are not in a flat area. Mountainous is the worst for digital. Digital TV today is roughly where analog color was in 1954... recall the grass turning pink and so on? FiOS + a great HDTV set will look great; compressed cable and satellite or a roof-top antenna in a hilly area... sorry.
- Says WBNG-TV (Binghamton, NY) Chief Engineer Chris Ball, “The digital signal doesn't bend and may not reach lower lying areas as well as the old analog signal does.” He suggests installing your antenna on the roof, instead of inside, for best results.
If you still aren't getting a signal, Ball suggests moving the antenna to another area of your home. “Either the antenna isn't large enough, or it's not pointed in the right direction; and when folks point it, they try to do it the same way they did with analog, just move it and watch the picture come in. What you have to do with digital is move it a little bit, let it sit and pick up the signal, and go forward from there,” says Chief Engineer Chris Ball.
The following table is rather long. The conversion to digital-only TV is complex, more so than many would admit. There are many possible situations, and there are often multiple responses to each. One reads that the transition from analog to digital-only TV is a "piece of cake". We often hear→ "If you have an analog TV with an antenna, you can simply buy a new digital (usually HDTV) set, or you can purchase a converter box with a $40 government subsidy; or if you prefer, you can get Satellite, FiOS, or Cable service. Many simple choices for you to deal with just one simple conversion."
The Facts→ There is little about converting from analog to digital-only that is simple. For folks who’ve been receiving free TV signals through an antenna, the transition isn’t a simple matter of obtaining a converter box and connecting it. Going digital may have them buying additional equipment and removing objects outdoors that interfere with digital or UHF reception. Even newer TVs with digital tuners won’t capture the range of channels viewers are used to if they’re not paired with the right antenna.
“It’s not a simple thing of getting a box, hooking it up, and you’re all set,” Cliff Soemann, an engineer with WIVB-TV (Buffalo, NY) said. “There are going to be a lot of people who didn’t know or didn’t understand. ... Once this happens, there are going to be a lot of unhappy people.” In some cases, they may find that free TV is no longer an option.
| YOUR TV SET |
YOUR TV PROGRAMS COME FROM... |
YOU WILL NEED BY 12 JUNE 2009... |
WILL YOUR TV DISPLAY PROGRAMS IN HIGH DEF? |
| "OLD" ANALOG TV WITH ONLY AN NTSC TUNER8 |
Over-The-Air... Roof-top Antenna Or "Rabbit-Ears"2 |
Converter Box With $40 Subsidy (Or New Digital TV)7 |
NO. You Can Watch Them In Analog (480i30) Using Converter Box |
| "OLD" ANALOG TV WITH ONLY AN NTSC TUNER |
100% Low-Power Analog Stations Over-The-Air With Roof-top Antenna Or "Rabbit-Ears" |
Nothing Needed For 12 June 2009 Conversion |
NO. None Will Be Broadcast By Low-Power Analog Stations |
| "OLD" ANALOG TV WITH ONLY AN NTSC TUNER |
Over-The-Air... In Your RV Or Moving Trailer Or In a Tour Bus |
The Current ATSC Digital System Selected Won't Permit Receivers In Motion Or Converter Boxes In Motion6 |
N/A |
| "OLD" ANALOG TV WITH ONLY AN NTSC TUNER |
Cable | You May Need To Start Renting Digital Cable Boxes From Your Cable provider If They Convert To 100% Digital Cable *Check With Them* |
NO. You Can Watch Them In Analog (480i30) |
| "OLD" ANALOG TV WITH ONLY AN NTSC TUNER |
Verizon FiOS | All FiOS Is 100% Digital Whatever You Have Now Is Fine |
NO. You Can Watch Them In Analog (480i30) |
| "OLD" ANALOG TV WITH ONLY AN NTSC TUNER |
Satellite | You May Need To Start Paying For More Stuff From Your Satellite Provider5 *Check With Them* |
NO. You Can Watch Them In Analog (480i30) |
| "OLD" ANALOG TV WITH ONLY AN NTSC TUNER |
You Watch Only Mexican Or Canadian Analog TV Stations |
Nothing Needed For 12 June 2009 |
NO. HD Requires Digital Transmission |
| "OLDER" HD-READY TV BOUGHT A FEW YEARS AGO |
Over-The-Air... Roof-top Antenna Or "Rabbit-Ears"2 From Digital Stations |
Buy HD-Capable Tuner For Over $100 No Coupons Apply1 |
If The Program Is Broadcast In HD, YES. |
| VIDEO MONITOR HAS NO TUNER OF ANY KIND |
Over-The-Air... Roof-top Antenna Or "Rabbit-Ears"2 From Digital Station |
Buy HD-Capable Tuner For Over $100 No Coupons Apply1 |
If The Program Is Broadcast In HD, Yes. |
| "OLD" ANALOG TV WITH ONLY AN NTSC TUNER |
Old VCR Casette Player | Nothing Needed For 12 June 2009 If Not Recording; $40 Subsidy Converter Box If Recording |
NO. You Can Watch Them In Analog (480i30) |
| "OLD" ANALOG TV WITH ONLY AN NTSC TUNER |
Blu-ray Disc Or Older DVD Players |
Nothing Needed For 12 June 2009 If Not Recording; $40 Subsidy Converter Box If Recording |
NO. You Can Watch Them In Standard Def |
| DIGITAL MONITOR |
Over-The-Air... Roof-top Antenna Or "Rabbit-Ears"2 |
HD-Capable Tuner Over $100 No Coupons Available1 |
If The Program Is Broadcast In HD, YES. |
| DIGITAL TV | Over-The-Air... Roof-top Antenna Or "Rabbit-Ears"2 |
Possibly New Antenna | If The Program Is Broadcast In HD, YES. |
| DIGITAL TV | Over-The-Air... In Your RV Or Moving Trailer Or In a Tour Bus |
The Digital System Selected Won't Permit Receivers In Motion Wait For ATSC-M/H 2009→ |
N/A |
| DIGITAL TV | Cable3 | Nothing Needed For 12 June 2009 |
If The Program Is Broadcast In HD And You Subscribe To HD, YES. |
| DIGITAL TV | Verizon FiOS | Nothing Needed For 12 June 2009 |
If The Program Is Broadcast In HD And You Subscribe To HD, YES. |
| DIGITAL TV | Satellite | Nothing Needed For 12 June 20091 |
If The Program Is Broadcast In HD, And You Subscribe To HD, YES. |
| DIGITAL TV | Digital Video Recorder | Nothing Needed For 12 June 2009 |
If original recording Is An HD Broadcast YES. |
| DIGITAL TV | The New Generation Of DVD Players (Blu-ray) |
Nothing Needed For 12 June 2009 |
If The DVD Is HD, YES. |
1. To watch HD broadcasts, you MUST connect your set-top box (or DVR or whatever decodes your digital cable or satellite) to your HDTV set with three component video cables; if your set-top box or DVR has an HDMI output, then get a quality HDMI cable and use that instead of component video (it's better). Composite video, or S-video, or a single coaxial cable will NOT ever carry an HD broadcast, unless Maxwell's equations decide to change.
Again→ If you have an HDMI output, connect it to your HDTV set with an HDMI cable; otherwise, use three component video cables (and usually two more for the sound). This is the #2 reason for never receiving HD broadcasts and thinking that you are. (The #1 reason is selecting the analog channel on cable or satellite instead of the digital channel.) Note that you only get HD when the digital channel that you are tuned to "decides" to send HD.
2. Some TV stations that broadcast in analog on the VHF band (Channels 2-13) will be broadcasting on a UHF channel (14-51) after the transition to digital. By the same token, some UHF analog stations will end up on channels 2-13. There is no hard and fast rule.
As a result, you may need to add a new rooftop antenna... UHF or VHF or both. This Web site→ http://www.antennaweb.org may be helpful in selecting and orienting your antenna.
Note that many roof-top antennas now pulling in analog stations will not receive one or more of these stations when they convert to digital-only; a new antenna (possibly with an amplifier) may or may not help. The US Government pays nothing toward a new antenna, and it offers no advice. You are on your own. This will be a special problem in mountainous and hilly areas, where digital does poorly; and for the elderly, folks with poorer vision, and the non-technically minded. It is also a great opportunity for rip-offs in vast over-charges for antenna installation.
(Precise Networking Solutions does not install or adjust rooftop antennas. They're not all that lithe. They do, however, install converter boxes.)
(In Britain, where a similar conversion is taking place, but market by market, smaller to larger (London is slated to convert in 2012), 7 million eligible folks contribute $40 as their area converts (if they wish); they get a converter box, they get it installed, they get any technical help they may need including a new antenna and installation; they get everything they need until their digital reception is working, including a phone number they can call for subsequent problems. But then again, Britain always was ahead of the US in TV, what with its 625 analog lines of resolution and its 8 MHz bandwidth for color. Sorry, it's true.)
As the chief engineer of a TV station in New York State put it, "Digital does not bend like analog did." If you are in a low-lying area, you may need a rooftop antenna, and you may need to try it in multiple positions and directions, and it still may not bring in the station you want. (It's not easy to transmit THREE 0's or 1's over-the-air (Trellis Numbers) 10,760,000 times each second, especially when you're forced to do it in 6 MHz.)
3. If you have an HDTV set, and if the set has both an ATSC digital tuner and a cable QAM tuner ("Cable-ready"), you should be able to receive those HD broadcasts that your cable provider is required (by the FCC) to carry, without the need for a set-top box or a subscription (i.e., it's free, "clear QAM"); but you will not be able to receive many non-broadcast HD channels (which is most of the HD universe→ Discovery HD, HD HBO, A&E HD, SciFi HD, ESPN HD, etc). This applies only to cable subscribers.
4. In January and February, Congress and the FCC changed the rules on when stations may transition. This note no longer applies.
5. In some areas, with some satellite providers, folks use an antenna to receive some or all of their local stations. If you use an antenna to receive local stations, AND if you have an analog TV set, you'll need to get a $40 subsidy converter box to continue receiving your local stations over the air. First, verify this with your satellite provider.
Example→ Our friend has had to purchase two converter boxes, even though she has satellite. She’s not allowed to purchase NBC from her satellite provider, for reasons that no human understands. Thus, she has to get NBC via rabbit ears connected to converter boxes. She can pick up a crisp digital WVVA (West Virginia) signal by using the old rabbit ears and the boxes. (Technically, she is supposed to purchase new television antennas; but the old rabbit ears with the converters seem to work fine for our friend.)
6. If you presently watch DVDs in your RV or Van or SUV or moving trailer (whatever), motion will NOT be a problem; the problem only occurs with
over-the-air reception of digital broadcasts. You can't be in motion; digital transmissions are VERY sensitive, and sampling must be very precise.(UPDATE→ The problem with the original ATSC standard is its physical layer cannot handle moving receivers. A new compatible standard has been developed by the ATSC (ATSC-M/H = ATSC Mobile/ Hand-Held) and can be deployed now (2009). ATSC-M/H requires additional broadcast equipement (a new "Exciter" that is backward-compatible with the existing 8-VSB exciter, think $200-$300,000) and new "in-motion" receivers. Stay tuned.)
7. Digital TVs and HDTVs are NOT the same thing. HDTVs are a type of digital TV. All HDTVs are digital. But all digital TVs are not HDTV. Non-HDTV digital sets are cheaper than HDTV sets, and either will solve your conversion problem just fine. You do not need a converter box of any kind with a digital TV. But what you may well need is a new antenna on your roof, and copious technical assistance. Note that connecting a converter box to an HDTV set is a VERY BAD IDEA; it will convert 720p and 1080i broadcasts to 480p, and you will forever lose HD.
8. If your TV has an antenna ("rabbit-ears" or rooftop), and it displays "snow" when you tune to a channel where no station is broadcasting, you have an "OLD ANALOG TV".
Summary→ Which Old Analog TV Sets Will Continue Working After
VCRs & Converter Boxes→ Old VCRs should be able to tape a program using a converter box, but often
only the program that the box is currently receiving. There are, however, converter boxes that have a VCR timer that
will turn on or change the channel on the converter box so that your VCR can automatically record from various different
channels; e.g., The Zinwell ZAT-970A.
What To Expect→ In mid-June, the last and largest 971 analog TV broadcasts were turned off. And if you get your TV programming through rabbit-ears or an antenna on the roof that picks up over-the-air broadcasts, and if you have an analog TV (old), your arrangement stopped working sometime prior to 12 June or on that date. (A few stations will weaken (or gradually weaken) their analog signal before cutting it off; others will begin broadcasting a repeating message about what is going on and what you can do about it.
Selling a converter box that can convert ATSC digital into NTSC analog for $40-$70 sounds to your dog Wolf like far-fetched; but it's 2009, and it's being done. Dr. Steve opens a converter box, looks around inside, and mutters “Hrmph, 25 dollars at most, parts and assembly”. And of course, the digital cable decoder boxes that you rent from the your cable provider work fine in coverting "Digital Cable" into a an analog NTSC signal. Mirable dictu. These are surely exciting times in which to convert TV signals.
Reminder→ You don't want a converter box for any TV that is hooked up to cable, or to satellite, or to FiOS. Analog TVs will continue to work with cable, satellite, VCR playback, DVD playback, camcorder playback, video games, and other devices for many years, without a converter box.
Danger→ If you have an HDTV or non-HDTV digital set, do not connect it to a converter box. The box will work fine... in down-converting every broadcast that you can receive (including HD) to 480p30 with a 4:3 aspect ratio, which is ED (Enhanced Definition)... trust us on this one. Far better that you let your expensive HDTV or non-HDTV digital set decide how to display stuff than some unnecessary converter box. Remember, HDTV and non-HDTV digital TVs do not want or require converter boxes.
Just remember, no matter what is being transmitted in digital, it can never be HD if it goes through a converter
box.
Boxes And Boxes→ If your TV is labeled "Digital Monitor" or "HDTV Monitor" or "Digital
Ready" or "HDTV Ready", this does not mean that it contains an ATSC digital tuner. These are "DTVready"
sets. You will want to add an ATSC tuner box... but not a converter-box. Again→ You want a box
which contains an ATSC digital tuner in order to view
Everyone is telling you→ Get a converter box or buy a digital TV or subscribe to a service like cable. But if you cleverly bought a DTVready television before 2005 (or if you have a "digital TV capable" computer monitor), you can buy an ATSC tuner for it for about $150. The Samsung DTB-H260F is an example of a nice tuner that you can connect to your older DTVready set.
The Samsung tuner will tune and decode all 18 ATSC video formats. You can watch both HD and SD. You can decode Dolby Stereo and Dolby 5.1 Surround Sound. And it has both HDMI and Component Video outputs. This ATSC tuner is perfect for folks who were wise enough to get a DTVReady TV back before 2005.
Again→ This digital tuner is not the same as the NTIA program
To Receive Over-The-Air Broadcasts With An Antenna→
If you can't determine whether your TV (or other television-related equipment, e.g., a VCR) contains a digital tuner,
check your equipment for the manufacturer name and model number, and then contact the retailer where you bought the set,
or the manufacturer, to determine whether it contains a digital tuner. (This information also may be available online on
the manufacturer’s Web site.)
1,295 full-power stations ended up by 12 June 2009 on a different channel for their final permanent digital broadcast channel from their old long-time analog channel. Some stations are moving from UHF to VHF. And UHF antennas cannot pick up channels 2-6. You well may need a VHF/UHF rooftop antenna before or after 12 June; or a VHF/UHF set of rabbit ears (with the smaller antenna between the long ears). Unlike Britain, the US is providing no assistance in paying for a new antenna, installing it, or providing technical advice.
Above all, don't be ripped off by folks charging outrageous fees for providing and installing rooftop antennas. A rooftop antenna should cost $20 (bare bones) to $200 (the best) plus installation and cabling. If the total for the antenna and installation is too many $$$, seriously consider a basic package (like $30/month) from a satellite provider such as DISH, especially if you live out in the country.
THE LAW I→ With passage of the Telecommunications Act of 1996, your local Home Owners (or Condo) Association is prohibited by Federal Law from enforcing any local laws or policies that ban, or even delaying mounting of, a satellite dish that is less than 39 inches (1 meter) in diameter. They can't even require you to request permission to put the dish on your roof or balcony. And once the antenna is up, they can't make you take it down or even move it, unless you have created a safety hazard (which they must prove to the FCC) or you live in a historic district (must be listed in the National Register of Historic Places). If your HOA or Condo Association is hassling you about a satellite dish you have installed or are planning to put up, contact the FCC at 202-418-0163.
THE LAW II→ Under Federal Law, you have a right to install an outdoor antenna to receive local television
stations, even if you are renting your property or subject to a homeowners' agreement. Such agreements can restrict only
where you may install the antenna or how high it may be, but they (generally) can't prevent you from having one. Don't let
'em tell you "no". (Beware of "HDTV" antennas. You don't need an "HDTV" or "digital television" antenna to get digital
signals. Digital transmissions are sent over the same airwaves that were used by analog, so you can use the same types of
antennas as before. In fact, buying an "HDTV" antenna can be a bad thing; some "HDTV" antennas will only get UHF signals.)
VERY IMPORTANT→ RESCANNING→
This is very possibly the most important conversion factor to consider if your programs come into your home via an antenna.
After you install a converter box, you'll need to rescan (AKA, "autotune") to make sure that all of the digital stations broadcasting in your area are being received. Some boxes will do this automatically; with others, it may need to be done manually. (Rescanning will make sure that all the digital stations in your area that CAN be received ARE being received; there surely may be digital stations in your area that you cannot receive. Rescanning won't help this problem.)
Rescanning the converter box and TV set for new channels after installation should ensure that all of the digital stations broadcasting in your area are being received. Also, because many digital stations that are already on the air may be moving to different channel numbers at the end of the transition period, it's a good idea to rescan again after 12 June. And then again and again. (Rescanning is like spraying with saline after sinus surgery; you can't do it too often... rescanning every day or every week after 12 June is not irrational; lots of things are still in motion.)
Warning→ Some converter boxes do NOT scan well; if you are missing digital stations that you know are out there, start by manually inputting all digital stations into the converter box, instead of doing an automatic scan.
Hint→ Probably the simplest way to handle rescanning is to unplug your box and/or television from the electric socket for about five minutes and then plug it back in and turn it on. The box and/or television will think it's in a brand-new market and start scanning for signals. (How well this works, and if it works at all, depends on the TV and the box and exactly how they store the data.)
Coupon-eligible converter boxes can do a scan looking for available channels. However, with some boxes you can't add channels to your viewing list without also deleting channels. The FCC says this can be important to some viewers, like those living between two cities who have to reposition their antenna to receive different stations. With some boxes, channels are added by an automated scan. With others, channels may be entered directly from the keypad. And some allow both.
DOUBLE RESCANNING→
In cases where stations moved their digital frequencies, simple rescanning may not be enough. A procedure called "double rescanning" can clear your box's memory of saved channels. Your earlier scans may have saved channel information that's now incorrect. There are five steps to a double rescan, either for a converter box or for a digital TV→
Click here for more scanning tips in the DTV category called
"Install a Converter Box."
Still Having Digital Reception Problems?→ Here are some suggestions from the FCC→
You'll also find information on fixing reception problems when you click here.
If you've tried these suggestions and you're still having problems, a local support center may be able to help. Click here to find one in your area.
-OR-
HELP→ If you need help in rescanning, if the manual that came with your box and/or TV is confusing, don't
hesitate to call the FCC help line at→
Batteries→ At least one converter box can operate off of a pack with six D-batteries (the Winegard
RCDT09A converter box). This should work fine with any analog TV that is battery operated, as long as the box is not
in motion. The digital transmission system approved by the FCC won't work if the converter box is in motion. Nor will a
digital TV work if it is in motion. (Yet. The new ATSC-M/H standards of 2009 allow manufacturers to begin deploying
digital sets that work when in motion; stay tuned.)
Closed Captioning→ The certified converter boxes do support closed captioning. With the most basic boxes, closed captioning is turned on or off by controls on the TV. Some converter boxes work with advanced captioning systems. Using controls on the converter box, viewers can access additional features, such as customizable font color and size and screen position for closed captioning.
Secondary Audio Programming (SAP)→ With digital, broadcasters can include as many as four separate audio channels with each television program. In addition to foreign languages, the "SAP" channels may be used for services such as a voiceover describing the action on the screen as an aid to people who may be vision-impaired. Some converter boxes allow access to only one SAP channel; if SAP is important to you, check on this.
Remote Control Features→ The FCC says all "coupon-eligible" converter boxes include some form of remote control. Some boxes include universal remotes which also work with TV sets and sometimes also can control DVD players or other electronic devices. Most converter box remotes include an SAP button; but in a few cases, SAP services can be accessed only through TV controls. Another factor to consider is the size of the buttons. Some viewers like large buttons, but smaller buttons generally mean a smaller remote.
Analog Pass-through And Border Areas→ Another feature that may be important is "analog pass-through." Some
stations will be digital-only; some will be analog only (low-power, etc). To continue receiving analog stations, you must
have a box with "analog pass-through". Viewers in border communities also may watch Canadian or Mexican stations. In these
situations, you'll also need a converter box supporting analog pass-through.
Getting Your Box To Work→
Check Your Connections→ Check that your converter box is connected properly. Make sure that your antenna is connected to the "antenna input" of your converter box. Ensure that the "antenna output" of the converter box is connected to the antenna input of your old analog TV. If you are unsure of the proper connections, refer to your converter box owners manual.
Make sure that your components are plugged in and turned on. Tune your analog TV to channel 3. You should see a set-up menu or picture on your screen. If you do not see this, re-check your connections.
Perform A Channel Scan→ Converter boxes have a button... usually on the remote control... that is labeled "Set-up" or "Menu" or some similar term. Press that button to access the set-up menu. Using the directional arrow buttons on your remote, scroll to the option that allows you to perform a "channel scan". The channel scan will search for digital broadcast channels that are available in your area. If you are unsure how to do a channel scan, refer to the owners manual for your converter box. Once the channel scan is complete, you will be able to tune to the digital channels received by your antenna.
Adjust Your Antenna→ Small adjustments to an antenna can make a big difference; digital TV is no exception. If you have an indoor antenna, try elevating it and moving it closer to an exterior wall of your home. After adjusting your antenna, perform another channel scan to see if your reception has improved. While adjusting your antenna, it may be helpful to access the "Signal Strength Meter" on your converter box to determine whether your adjustments are improving the signal's strength. You probably can find your signal strength meter via the "Menu" function on your remote control, and your owners manual will provide detailed information on how to perform this function. Remember to do another channel scan after you have adjusted your antenna.
Make sure that you are using an antenna that covers both the UHF and VHF bands and that is connected properly (depending on which channels are in use in your area).
Aspect Ratio 4:3→ Your converter box should work fine with an analog "square" (4:3) TV. There should be no format problems. Be sure that the converter box output is 4:3 (not 16:9). This is easily selected on the box's menu. Anything that's widescreen (WS) will display with black bars above and below. You normally can change the viewing format (aspect ratio) simply by pressing a button on the remote.
BRAND NAME |
MODEL NUMBER |
PRICE LESS $40 |
PICTURE QUALITY |
SPECIAL FEATURES |
| AccessHD | DTA10100 | $60-$40=$20 | A- | |
| Alpha Digital | AT2016 | $55-$40=$15 | A | |
| Dish Network | DTVPal | $60-$40=$20 | C | Passes Low-Power Analog; Facilitates VCR Channel Selection |
| Microgem | MG2000 | $65-$40=$25 | B | |
| Philco | TB100HH9 | $50-$40=$10 | C | Passes Low-Power Analog |
| Sansonic | FT300A | $55-$40=$15 | A- | |
| Tivax | STB-T9 | $50-$40=$10 | A | |
| Winegard | RCDT09A | $68-$40=$28 | C- | Can Run On Battery; Winegard RC-BP9V $15 Battery Pack |
| Zinwell*** (Our Favorite) |
ZAT-970A | $50-$40=$10 | A+ | Passes Low-Power Analog; Facilitates VCR Channel Selection |
Prices shown above for converter boxes include the $40 NTIA government subsidy coupon. Call
***The Zinwell ZAT-970A converter box is a good all around box. It comes with the analog pass-through feature. The picture of the Zinwell ZAT-970A TV converter box is very good. It provides a picture that is a very significant upgrade over analog television. This TV converter box's picture rates at just below the top TV converter boxes. The sound is very good. It provides viewers with a very crisp sound that rivals top converter boxes.
The ZAT 970A converter box comes with the ability to search for all channels at once or set channels one by one. Finally this box comes with an electronic program guide that is better than most other boxes. The Zinwell ZAT-970A TV converter box provides a great set of features, also selling below $55, which makes it an affordable buy.
TROUBLESHOOTING GUIDE→ In early October 2008, the FCC released a short online consumer DTV Troubleshooting Guide for Converter boxes and Digital Television. This guide provides a connections checklist and tips on reception of digital signals. It answers questions and provides tips to consumers who may be having difficulty receiving digital broadcast stations in specific areas.
For this additional information, click on this link→
http://www.fcc.gov/cgb/consumerfacts/troubleshootguide.pdf
This is probably as good a point as any in our journey through High Definition to slow down, take a deep breath, and compare all the rules and theories with the cold, harsh world of The Realities of Digital TV and Converter Boxes, and stuff like that. So here we'll take just a moment to separate the wheat from the background noise.
Better digital picture quality? Better digital sound quality? Why is it better?
One important reason that digital TV appears to be sharper and clearer than analog is that analog signals can be affected by interference and still viewed on our TVs, although at degraded quality. Yeah, we may see snow and lines, and the sound may not be the clearest, but your dog Wolf still could watch the Washington Redskins at home from an analog TV station 60 miles away in DC.
In contrast, digital transmissions either come in with a strong clear signal or they are unwatchable with no sound; so if we're able to view a digital channel at all, that usually means that the signal is going to be good... because digital TV throws out all the channels that are not strong and sharp and clear. With analog, the picture and sound are independent; with digital, they are integrated. A weak signal not only makes the picture unwatchable, it kills the sound too.
And the price that we pay is that channels that we received in analog that were a little fuzzy or snowy are simply not
going to show up at all in digital. Better picture quality? Better sound quality? These are the "bright and shiny objects"
intended to distract folks from the utter complexity (and frustration) of the conversion to digital-only TV.
Remind Us Once Again, WHY THE SWITCH TO DIGITAL?→
An important benefit of the switch to digital-only broadcasting is that it will free up parts of the broadcast spectrum for public safety communications... police departments, fire departments, rescue personnel, etc... a whopping four channels→ 63, 64, 68, and 69. Also, some of the spectrum will be auctioned to companies that will be able to provide consumers with more advanced important wireless services, such as Super-iTexting and Ultra-iTwitter. So we have Four Channels for public safety, and we have Fourteen Channels, including the prime 52-59, auctioned off (and to be re-auctioned... yes, the former FCC mucked up the first auction) for a fortune ($$$) to telephone companies who stand to make a MFo (Mega-Fortune, $$$$$.)
Digital is more efficient than analog. For example, rather than being limited to providing a single analog program, a digital broadcaster is able to offer a super sharp "High Definition" (HD) digital program (if the viewer has an expensive super sharp HDTV set); or she simultaneously can provide multiple "Standard Definition" (SD) digital programs through digital "multicasting". (Ok... We understand, so every full-power TV station gets several highly valuable additional broadcast licenses at no additional charge ($$$$$)... including programs like the ones that only doctors' offices receive, the ones that plug meds.)
Multicasting allows broadcast stations to offer multiple digital programs at the same time, using the same amount of spectrum required for one analog program, 6 MHz. (Of course, the more programs offered in a digital channel, the worse they all will look... and there goes our "better picture, better sound". (See "No Free Lunch" Theorem.) )
Therefore, while a station broadcasting in analog on channel 7 is able to offer viewers only one program, a station broadcasting in digital on channel 7 can offer viewers one digital program on channel 7-1, a second digital program on channel 7-2, a third digital program on channel 7-3, and so on.
That could translate to more programming choices for viewers (assuming he can receive channel 7 in digital). Of course, viewers looking for more choices in programming could have gotten cable; that would give them hundreds of choices... and viewers requiring still more choices could either subscribe to Netflix or learn to read.
Broadcasters also have the option of running a breaking news story on one of their sub-channels, while leaving network
or regular programming on another sub-channel. For example, during the recent Rod Blagojevich impeachment trial, one ABC
station showed the impeachment coverage on one of its digital sub-channels, while running soap operas as normal on another
sub-channel; and with a little thought, they could have been showing the daily morning high-speed LA car chase on still a
third sub-channel. (Anything that increases the legitimate news content from over-the-air broadcasters is a plus for
democracy.)
DIGITAL-------->SET-TOP BOX--------->======ONE HDMI CABLE=========>HDTV SET (Best)
CABLE TO DECODE |
ENTERS DIGITAL CABLE |=====>5 Component Cables=====>HDTV SET (2nd Best)
HOUSE (WITH HD SUBSCRIPTION)
|
|
|---------->DIGITAL VIDEO-------->======ONE HDMI CABLE=========>HDTV SET (Best)
RECORDER (DVR) |
(WITH HD SUBSCRIPTION) |=====>5 Component Cables=====>HDTV SET (2nd Best)
CABLE--------->SATELLITE------------>======ONE HDMI CABLE=========>HDTV SET (Best)
ENTERS HD RECEIVER |
HOUSE SET-TOP BOX |=====>5 Component Cables=====>HDTV SET (2nd Best)
FROM (WITH HD SUBSCRIPTION)
SATELLITE
DISH
|
THE NITTY GRITTY→ Unless your antenna is receiving an over-the-air broadcast, you will need to connect the digital decoder box that you rent from your cable or FiOS or satellite provider to your HDTV set. You have two choices in your cabling→
THE REAL STORY→ Dog Wolf... Help. We need an explanation of why HDMI on the DTE (Data Terminal Equipment) side of the set-top box is better than just a plain old coaxial cable. Like, the signal arrives through a coaxial cable, so how can a different interface from the set-top box to your HDTV set provide a better (or worse) quality picture and sound?
ANSWER→ Let's assume that you receive digital cable. The set-top box is there to tune and decode "digital cable", NOT analog. And this is the key to why an HDMI interface is better than standard coax. With new display technologies, such as DLP, LCD, LCoS, and Plasma able to receive digital signals, and HDMI able to transmit uncompressed digital signals, the HDTV set is receiving the most error free signal possible. HDMI supports, on a single cable, any TV video format, including standard definition (SD), enhanced definition (ED), or high definition (HD) video, plus multi-channel (Dolby 5.1) digital sound.
If you were to use the RF output from the set-top box, or even use the S-Video or baseband outputs, the box still must first receive and decode the incoming digital signal, and then do a digital to analog conversion, then re-modulate the signal for use on an analog input on an HDTV set. As you can guess, you LOSE information in doing this, not even to mention that these outputs are not capable of carrying High Definition.
Even though the YPbPr outputs are capable of passing 1080i30, there is a Digital-to-Analog conversion that has inherent signal degradation. With HDMI able to transmit multi-channel digital audio as well as HD video, (not to mention the use of "EDID handshaking"), we surely would use HDMI over coax. In fact, the worst picture we've ever seen on a flat screen HDTV set was on a 52" 1080p60 LCD Samsung... the HDTV set was connected to a DVR box by a length of coaxial cable (either by a Big Box Store installer, or by Comcast.)
Even a "minimalist" cable box, which takes in its video content in analog form ("Basic" Analog Cable TV), will improve
the picture on the screen with an HDMI connection. Here, the analog signal is converted one time, in the set-top box, and
then sent to the TV in digital form over the HDMI cable. The analog-to-digital conversion in the set-top box is actually
quite good in most cases, even though the incoming analog is limited to Standard Definition (SD), and can never be HD.
(Remember we talked about no HD with analog cable? Great.)
Problems With HDMI→ There are three potential problems that will prevent you from using an HDMI cable and force you into using component cables→
Assuming that you have neither of these three problems, you want to use an HDMI cable. HDMI video quality is better than component cables. The HD picture using component cables is fine; but the picture with an HDMI cable is better.
Now, all HDMI cables are not created equal. We tried one from RadioShack, and the picture was comparable to component cables... still nice HD. But when we tried an HDMI cable that was purchased by Precise Networking from an alternate source, we improved our HD picture; you may want to experiment.
Just a few more words about HDMI... HDMI is a single cable that carries both uncompressed video and multiple channels of compressed Dolby sound. The video can be as "dense" as 4.95 GBit/sec (version 1.2 of HDMI), or 10.2 GBit/sec (version 1.3 of HDMI). We recommend using Version 1.3 of the HDMI cable. The HDMI 1.3 specification adds support for Deep Color technology, a broader color space.
(And remember that HDMI is not only a cable that carries high resolution video plus Dolby Surround Sound in digital
format, it’s also a standard; and that standard will continue to evolve, continue to incorporate new features to make
connecting various components easier, to support future higher resolution devices. The newest version of HDMI, announced
27 May 2009, is HDMI 1.4; it adds many new features that gradually will become more and more important to folks
over the next several years.)
DEEP COLOR→ HDMI 1.3 supports 30-bit, 36-bit, and 48-bit (RGB or YCbCr) color depths, up from the 24-bit depths in previous versions of the HDMI specification. This allows HDTV sets to go from millions of colors to billions of colors. It eliminates on-screen color banding, for smooth tonal transitions and subtle gradations between colors. (Banding is something bad; if you have an image with a smooth gradation from, say, black to red, and if your HDTV, instead of showing that smooth change, instead shows bands of several intermediate colors, then that is banding.) HDMI 1.3 also enables an increased contrast ratio.
HDMI 1.3 can represent many more shades of gray between black and white. At 30-bit pixel depth, four times more shades of gray would be the minimum, and the typical improvement would be eight times or more. HDMI 1.3 promises finer gradients between colors and a wider gamut (range) of displayable colors. It's a good idea to assure HDMI 1.3 cable compatibility when shopping for a new HDTV set.
The broader color space in version 1.3 of HDMI cables virtually removes all limits on color selection. Next-generation xvYCC color space supports 1.8 times as many colors as existing HDTV signals. HDMI 1.3 allows HDTV sets to display colors more accurately. And it enables displays with more natural and vivid colors.
Since the single HDMI cable carries uncompressed video (using the TMDS format), there IS some encoding/ decoding
performed at each end (decompression and recompression); but this is not as severe as component cables doing
The all-digital video with an HDMI cable is sharper than component connections; and using a single HDMI cable eliminates the softness and the ghosting occasionally associated with other types of connections. High contrast details bring out this difference the most. Be sure that your HDTV set accepts at least one HDMI cable.
However, component cables easily handle 1080p120, and the picture is never "bad"; it is just not quite as good as HDMI. Component cables, having to convert digital to analog at the set-top box, and analog back to digital at the HDTV set, is slightly "lossy"; detail is lost. Conversely, HDMI remains digital throughout.
(Yes, we know that DVD→HDTV requires reclocking with slight loss in picture quality using an HDMI cable; in our humble opinion, an HDMI cable still looks better than component cables. If you're unsure, as we were, simply try both; but use a quality HDMI cable.)
Separate video, abbreviated S-Video, with brightness and color separated, will not support HD.
ADAPTERS→ Many folks search for an adapter that will connect HDMI cables to Component Outputs. But such an adapter isn’t just a way to rearrange wires and have correct physical connectors. There is a basic analog versus digital incompatibility; and as we know from the June 2009 conversion, digital and analog signals are different. Component video connectors are based on an analog format, where the voltage in the wires is wavelike. And theoretically, ignoring "quantum effects" and noise, there are an infinite number of values the analog wave height can have, from 0 to some maximum amplitude.
On the other hand, HDMI is based on a digital format, strings of ones and zeros (bits). The information on an HDMI cable is reassembled by processing equipment at the far end (the TV end) of the connection. So equipment at the far side of the HDMI cable that is detecting signals and looking for analog sine waves, in the input marked "component cable", is up the creek; it will see only complete garbage from an HDMI cable; it just has received a string of zeros and ones. So what do we do, dog Wolf?
OK... There are some simple ways to handle these analog vs. digital problems. If both ends of the HDMI (or DVI) cable have HDMI connectors, things are simple, and they should be used. (DVI and HDMI differ in the fact that HDMI carries the audio and video signals in one cable, while DVI does not. DVI’s video quality is equivalent to HDMI; it just requires the use of an additional audio cable.)
If you want to use the Component outputs because the HDMI port is already tied up, there are HDMI switch boxes that are quite cheap, where you can plug multiple HDMI cables into one side with a single HDMI output on the other side. Make sense?
I Want What I Want→ If you have no other option, and you absolutely have to do a conversion from Component
to HDMI, you CAN get a special converter box, but it will generally be priced at over $200. (If you decide on a
special converter box to go between HDMI and Component, HDCP (High Definition Content Protection) access MAY be
denied, and your HD signal will be blocked on the way to your HDTV set for what HDMI interprets as "copyright
infringement". This is uncommon, but be careful. HDMI is almost too smart for its own good.
In order to understand "HD" (High Definition Television), we first must understand the new ATSC DIGITAL standards... especially the ATSC digital broadcast formats.
And for you PC purists, as we write these very words that you're now reading, we're seeing our words appearing (via "Notepad", nothing very fancy) on a 19" Optiquest computer monitor, a monitor being driven by an Intel 82865G Graphics Controller (in other words, nothing special).
But the image on this PC monitor's screen is VERY VERY sharp, and if we flip over to ULEAD, our image program... ah, there she is... our Irish Setter friend, a professor at Princeton she be, and if we look at her picture, full of the rich colors of her sensual red-brown coat... the image in front of us now is much sharper and clearer and more vivid than the picture on our 20" analog Sharp TV over there, also in our den, its sound turned down, running yet another Xmas movie. (They're all Xmas movies in December, just before Xmas; we love it... up to a point.)
Computer folks like to say that PC monitors have better resolution than the "old" analog TV sets... resolution refers to the fact that our monitor can resolve much finer details than our Sharp analog TV. So taking a peek at the settings on the monitor, it says "1024x768 pixels" at "75 frames per second". (Like most PC monitors, this one is probably displaying each image three times; in this case, it's displaying three images every 1/25th of a second... so there's no flickering here.)
From the shape of the monitor's screen, it looks like there must be 768 rows of pixels, with 1024 pixels on each row. (Pixels, or picture elements, are just the smallest parts of an image on the screen, the "dots", the molecules that make up all the images on this screen. And I think we set the "refresh rate" at 75/second because we hate flicker; DAwn always seems to get a migraine when we have flicker, and then we have to stop working for the night.
If we wanted to express our monitor's resolution in the standard "format code" that we talked about earlier, it would be 768 rows/ progressive (non-interlaced... all computer monitors are progressive)/ 75 frames per second... or simply→ 768p75, our PC monitor's "format code".
Anyway, it looks as if we have 1024x768x75 pixels per second on our PC monitor; and each pixel has its own brightness level and color. (Looks like we have the color set at 32-bits, which should give us a billion or two possible colors that we can see, along with quite a few that we can't; whatever... humans can separate about 10 million discrete colors.)
So 768 rows × 75 screens/sec = 57,600 rows/sec. So that's the "resolution" of this monitor screen, at the format of our current screen settings; we surely could play with these settings and bring up other formats, but we'd like to continue with the monitor working.
Now, we're not certain, but we have a feeling that all the rows of pixels on this monitor, and all the pixels in each row, and the speed at which the monitor is "refreshing" its screen (and even to some extent all the colors that we have available) have at least something to do with why this screen is so very much sharper than my Sharp TV, now displaying "It's a Wonderful Life".
Nothing against Sharp; we have had that set for many years, no problems, no adjustments... it's just not nearly the resolution that we have on our PC monitor... but what if... what if we could have a TV picture whose resolution was much closer to the screen of our PC monitor? Ok, back to ATSC digital TV...
The ATSC standards for digital television have "format codes" that are analagous to a PC monitor's formats. You can
vary the number of rows of pixels, you can vary the number of screens (frames) that "refresh" per second, the number of
pixels per line will vary, and so on. In fact. there are 18 digital ATSC TV formats. Here's a table listing
all 18 approved ATSC video formats, for your future reference→
| THE VIDEO FORMAT | HORIZONTAL LINES IN EACH COMPLETE FRAME (SCREEN) |
PIXELS IN EACH HORIZONTAL LINE |
ASPECT RATIO (WIDTH TO HEIGHT) | SCAN MODE Progressive ("p") Or Interlaced ("i") |
COMPLETE FRAMES (SCREENS) PER SECOND | FORMAT CODE |
| "Full High Definition" (1080p)** Non-ATSC |
1080 | 1920 | 16:9 | p | 60 | 1080p60 |
| High Definition | 1080 | 1920 | 16:9 | p | 30 | 1080p30 |
| HD (1080p24) | 1080 | 1920 | 16:9 | p | 24 | 1080p24 |
| HD (1080i)* | 1080 | 1920 | 16:9 | i | 30 | 1080i30 |
| HD (720p)* | 720 | 1280 | 16:9 | p | 60 | 720p60 |
| HD (720p30) | 720 | 1280 | 16:9 | p | 30 | 720p30 |
| HD (720p24) | 720 | 1280 | 16:9 | p | 24 | 720p24 |
| Non-Standard (Used Primarily By DirecTV For "HD") | 1080 | 1280 | 16:9 | i | 30 | 1080i30 |
| Enhanced Definition | 480 | 704 | 16:9 | p | 60 | 480p60 |
| ED | 480 | 704 | 16:9 | p | 30 | 480p30 |
| ED | 480 | 704 | 16:9 | p | 24 | 480p24 |
| ED | 480 | 704 | 4:3 | p | 60 | 480p60 |
| ED | 480 | 704 | 4:3 | p | 30 | 480p30 |
| ED | 480 | 704 | 4:3 | p | 24 | 480p24 |
| ED | 480 | 640 | 4:3 | p | 60 | 480p60 |
| ED | 480 | 640 | 4:3 | p | 30 | 480p30 |
| ED | 480 | 640 | 4:3 | p | 24 | 480p24 |
| Standard Definition | 480 | 704 | 16:9 | i | 30 | 480i30 |
| SD | 480 | 740 | 4:3 | i | 30 | 480i30 |
| SD | 480 | 640 | 4:3 | i | 30 | 480i30 |
| Just For Comparison The Old NTSC Analog |
480 | No Real Meaning |
4:3 | i | 30 | 480i30 |
* US HD broadcasts use one of two formats, either 1080i30 or 720p60. (Or so the story goes.) But MPEG-2 actually is quite flexible. Some NBC stations (and others) have been broadcasting with 1080p24 and 1080p30 formats. "Metadata" is broadcast along with the video and cues the decoder in your HDTV set to turn these 1080p rates into 60 interlaced 540-line fields per second (1080i30), to remove flicker. (How your HDTV set responds to this metadata is up to your particular set.)
** In addition to the two video formats used for HD broadcasts in the US,
1080p60 is defined by the ITU (International Telecommunication Union) as a standard for HD, though it is not
used for over-the-air broadcasts in the US.
SO... Imagine that the 18 ATSC approved digital TV picture formats are 18 steakhouses (all 18 approved by ATSC...
the FCC's "Zagat Of Digital"); then HD is the best six... Smith & Wollensky, Peter Luger, etc... the six digital
video formats, out of the 18, that are at the top in video quality, the six very best digital picture formats, the
six formats serving up only dry-aged, prime digital video steaks... the very best quality picture that is ATSC approved...
the best video resolution with the fewest migraine headaches from flickering. (One of DAwn's passions is a medium-rare NY
strip served up at some great steakhouse.)
THE REAL STORY→ If you are an engineering-type, you may like to have an engineering type definition for HD→ If the data rate from studio cameras and other video sources going into the Video Subsystem, where Video Source Coding and Compression take place is 1.0 GBits/sec (One Billion bits per second) or higher (1.485 GBit/sec is a very common number), then we say that the source of the broadcast is High Definition, and that we are almost always transmitting the program in High Definition.
At such a data rate, the video subsystem normally produces video at 720p60 or 1080i30 (different TV networks and TV stations use different video formats; e.g., ABC uses 720p60) almost always with an aspect ratio of 16:9. (Sometimes the original material will have an aspect ratio of 4:3, but it will have a data rate that "qualifies" for High Definition; the video subsystem will usually stretch the aspect ratio out to 16:9.)
EVEN DEEPER→ There is another subtle difference between HD and analog and non-HD digital. If for some reason a black and white source (an old Bogart movie, for example) is broadcast in HD, you may notice that it looks a little greenish; but if it's broadcast in SD (standard definition), it'll look fine.
Television creates black and white for "color sets" (like for all HDTV sets) by mixing red and green and blue. HD adds in a little more green than analog did (or SD digital does). HD does this because it allows a slightly wider range of colors to be displayed; and HD wasn't created with black and white in mind.
For the technical-minded, HD black and white brightness is created by mixing colors in these amounts→
SD and analog create a black and white picture by mixing colors in these amounts→
Some HDTV sets will try to correct for the "green anomaly", the result being that they may get it wrong occasionally...
it's not easy to detect the fact that B&W is occasionally HD in disguise; and some HDTV sets simply assume that everything
they receive is HD, assuming that even if it's not, one day it may be. And as for the 99.9% of broadcasts that an HDTV set
receives with color, everything usually looks fine.
IS 480p HD?→ 480p is not HD. 480p (the family that includes 480p60, 480p30, and 480p24) is defined in the US ATSC standards as ED (Enhanced Definition). (Folks who mistakenly connect a converter-box to HDTV sets... yes, they do... Precise Networking Solutions has had to "un-convert" several HDTVs... can watch all broadcasts as ED (with an aspect ratio of 4:3) .) 480i30 (SD) is de-interlaced by flat-screen HDTV sets to 480p30 before being displayed. EDTVs (Enhanced Definition TVs) display 480p fine, but they cannot display HD (720p, 1080i, or 1080p).
NOW... See all those wide screen, slightly expensive, HDTV sets on sale at the Big Box Stores? Flat-screen, mostly LCD and plasma? They are digital TVs... or more precisely, they are capable of receiving and displaying the digital channels that TV stations are pumping data bits into, just as our PC is currently pumping data bits into this monitor. And not only can they receive digital, but when that digital broadcast is HD quality, they can display the broadcast with HD quality.
You also can use the digital TV sets to watch the analog channels that will be around until June 2009 (longer for most low-power stations). NOW... During "The Transition" (i.e., until 12 June 2009), you can watch a digital TV broadcast (HD or non-HD) only if you (or your cable or satellite or FiOS provider) are tuned to the digital channel of the two transmissions that about 1,000 full-power US TV stations are still broadcasting (one an analog transmission and one a digital transmission).
To receive a digital transmission, you must have either a digital TV receiver (possibly an HDTV set) or a converter box or a digital cable provider or a satellite provider or a FiOS provider (all satellite and FiOS is 100% digital). But a program broadcast in HD only can come from the digital channel of the pair of channels, never from the analog channel.
Just as HD pictures are almost always displayed on your HDTV set's screen as wide (with a 16:9 width to height
ratio, called the "aspect ratio"), HD also is strictly a digital thing... and a compressed (MPEG-2) digital thing at that.
HD has meaning only in a digital context, just as my PC's Optiquest monitor only works if I connect it to something
digital... like to my PC. And after 12 June 2009 passes, all full-power US TV stations will be transmitting only in one of the ATSC digital video formats. No more analog broadcasts from full-power US TV stations. No more
"vinyl records". Strictly CDs and DVDs only.
THE REAL STORY→ OK... we just proclaimed that "High Definition" TV was the SIX BEST ATSC DIGITAL FORMATS out of the 18 ATSC APPROVED DIGITAL FORMATS. We said that HD was the six formats with the best video, the best picture, the highest resolution. And we'll stick to that. BUT... You may hear some "experts" insisting that HD is not the best six but the the best twelve of the 36 ATSC Digital Formats. (Please don't scream.)
The best 12 out of 36 possible video formats? HUH? What is this all about, dog Wolf?
WELL... It all has to do with the frame rates, the number of complete pictures displayed per second. Like, 1080 rows x 1920 pixels per row, displayed at 16:9 and at 30 frames/second is surely what folks normally mean when thay say 1080i, a short-cut for 1080i30. And most of the time, it works.
BUT... Sometimes we want to "integrate" the new ATSC standard frame rates with the old NTSC frame rates. And for reasons that we'll be examining shortly, the old NTSC frame rate is not exactly 30/second; it's almost 30/second, but to be very precise, it's actually 29.97 frames/second (29.97=30.000/1.001). Once upon a time, it was exactly 30/second, until 1953 came along, and compatible color TV came to the US and to the FCC and to NTSC.
Begin Urban Legend→
Deep→ Why did color create this mess? Weird numbers like 29.97 frames/sec had to be implemented for reasons involving the circuitry using vacuum tube TVs of yesteryear. (Nope, no transistors or chips yet.)
(Specifically, the fact was that vacuum tube circuitry occasionally lead to "non-linear distortion" (sounds insidious), and it was felt that color would create problems unless we changed the frame rate. These problems have long since been resolved, and there is no earthly need to use the weird numbers, but they're carved in stone as part of the NTSC standard of 2009... and besides→ Who wants to devote the rest of her life converting 40+ years of studio and network videotape back to 30.00 frames/second?)
Deeper→ When a TV transmitter broadcasts in NTSC analog, it amplitude-modulates the video carrier. Actually, it "Vestigial Sideband Modulates" the video carrier (VSB), but VSB is a form of amplitude-modulation, so we'll stick by our first statement here.
A second transmitter, a completely separate transmitter, frequency-modulates a sound carrier that's 4.5 MHz higher than the picture carrier. If "non-linear distortion" occurs, the 3.58 MHz color carrier may "beat" with the sound carrier = a dot pattern (in your old TV set). Or so the justification went. Anyway, to make this pattern less noticeable, engineers adjusted the original 60 Hz field rate down by a factor of 1/100.1%, to approximately 59.94 fields per second.
Still Deeper→ The 59.94 rate popped up as follows→ Designers chose to make the color carrier frequency an (n + 0.5) multiple of the line frequency to minimize interference between the luminance (brightness) signal ("Y") and the chrominance (color) signal ("C") (more coming up on these). Engineers then chose to make the audio carrier an integer multiple of the line frequency to minimize interference between the audio signal and the chrominance signal.
Yet Still Deeper→ The original NTSC black-and-white standard had a 15,750 Hz line frequency and a 4.5 MHz audio carrier; BZZZT... it didn't meet the above (n + 0.5) requirements, so designers either had to raise the audio carrier or lower the line frequency. Raising the audio carrier frequency would have prevented existing receivers from properly receiving the audio signal. But lowering the line frequency was comparatively innocuous, because the horizontal and vertical synchronization information in the NTSC signal allows a receiver to tolerate a substantial amount of "slop" in the line frequency. (And besides, RCA who was pushing the compatible color system sold a lot more TV sets than it did TV transmitters.) And so this is the route that the color NTSC standard took.
In the original black-and-white standard, the ratio of audio carrier frequency to line frequency was 4.5 MHz / 15750 = 285.71. In the color standard, this becomes rounded to the integer 286, which means the color standard's line rate is
4.5 MHz / 286 ≈ 15734 lines per second. Dividing by 262.5 lines per field, this gives approximately 59.94 fields per second. Q.E.D. (Quite Easily Done.)Or so the story goes.
←End Urban Legend.
THE REAL STORY→ There are countless articles attempting to explain why with the advent of color, the field rate went from 60.00 fields/ second to 59.94 fields/ second, so that the color carrier and the FM sound carrier would not beat against one another (in TV sets) and create unusual patterns superimposed on the picture on the screens of TV receivers.
BUT... It is the opinion of many wise folks that the field rate modification for color was simply an error and was unnecessary. For one thing, the NTSC sound carrier is FM. This means that the frequency of the sound carrier is constantly changing; any beating between the color carrier and the sound carrier would thus be unsteady and not visible. (Uh oh, what did we do, playing around with the frame rate?)
Moreover, a higher chrominance carrier frequency could have been used, and the audio carrier increased slightly to make the difference signal fall on the right multiple of the scan rate; and despite the change, most black and white TV sets would have tolerated it totally, by 1953.
However, the TV manufacturers' association (lead by RCA) objected, and so the decision was made to leave the carriers roughly where they were and change the horizontal scanning frequency, and thus, change the frame rate instead. This decision didn't make transmitter manufacturers or TV stations happy, because it meant many expensive alterations to transmission equipment; and the AC line (at 60 Hz) could no longer be used as a frequency reference for "sync".
At a minimum, one can diplomatically call the decision to change the frame rate “debatable". By 1953, the very first generation of color sets, and also the black-and-white sets that were made by the time the color standard was adopted, had sufficient filtering on the audio section that leakage between the sound and color carriers simply was not an issue. Sadly, it looks like 59.94/sec may carry over to High Definition and to "No More Analog" for quite a while, or most likely, forever (or until the basic principles of television change, around the year 2050 or so).
Since most HD (and non-HD) digital broadcasts have been simulcast with analog NTSC, to keep the two broadcasts in sync, the HD broadcast is sent out with a frame rate of either 720p59.94 or 1080i29.97. Once the old NTSC analog broadcasts from full-power stations bite the dust in mid-June 2009, one can only hope that the commonly used frame rates will become integers (like 720p60). (Ever watch the TODAY SHOW "jump" when you're about to go from the HD broadcast of the NBC weather to your local weather, and a few frames are out of sync timewise?)
In HD, in any ATSC digital for that matter, HD or non-HD, there is no need for reducing the frame rate slightly to prevent interference between the sound and color carriers (assuming that there ever was); carrier interference cannot occur in ATSC digital TV.
WHY?→
Since ATSC digital has no color carrier and NO sound carrier and not much of a video carrier, there simply are no carriers, and no carriers cannot "beat" together with each other.).
So to be overly technical, the ATSC standards really do allow for 12 HD formats, although each format code in each pair differs from the other code in the pair only in having a very slightly different frame rate. Like the pair→ 720p60 and 720p59.94.
Technically, the following table lists the ATSC HD formats. (Once you look at this table, please forget it. We just wanted to prepare you for arguments at dinner parties and at Saturday morning tailgating on just how many different HD formats there really are... technically 12, but for all sane purposes just 6.)
REVIEW→ In the beginning, like 1946, the old analog NTSC frame rate was a pure 30/second, because in the beginning, NTSC was solely a black and white thing. The frame rate was reduced to 29.97/sec after color was introduced in 1953. WHY? Because the color "carrier" MIGHT interfere with the sound "carrier" inside your TV.
By reducing the frame rate by just a hair, so the story goes, this possible interference was reduced. Prior to color, the "time code", based on exactly 30 frames/sec, made isolating a scene for editing a breeze; but at 29.97/sec... YOIKS. And so the "drop frame time code" had to be introduced.
THE REAL STORY→ Some very junior engineer came into work with a really bad hangover on New Years Day, his color TV project that was to have been completed still unfinished. Suddenly, an idea came to him. "I'll come up with some new but meaningless unit called RIPS; and when one does some meaningless calculation with the meaningless RIPS... why, then we'll compute that the frame rate must be reduced to 29.97/ second... or else... or else the sound carrier and the color carrier will "beat" together, I'll tell them; and they may buy the whole thing, and maybe they won't even recall that the sound carrier is FM. And hey, I may even get a patent for RIPS."
| THE VIDEO FORMAT | HORIZONTAL LINES (ROWS) IN EACH COMPLETE FRAME (SCREEN) |
PIXELS IN EACH HORIZONTAL LINE |
ASPECT RATIO (WIDTH TO HEIGHT) | SCAN MODE ("p" OR "i") |
COMPLETE FRAMES (SCREENS) PER SECOND |
| High Definition (1080p30) |
1080 | 1920 | 16:9 | Progressive | 30 (or 29.97) |
| HD (1080p24) |
1080 | 1920 | 16:9 | Progressive | 24 (or 23.98) |
| HD (1080i30) |
1080 | 1920 | 16:9 | Interlaced | 30 (or 29.97) |
| HD (720p60) |
720 | 1280 | 16:9 | Progressive | 60 (or 59.94) |
| HD (720p30) |
720 | 1280 | 16:9 | Progressive | 30 (or 29.97) |
| HD (720p24) |
720 | 1280 | 16:9 | Progressive | 24 (or 23.98) |
Review→ In a progressive transmission (e.g., 720p60), every scan line in a frame is broadcast sequentially... 1,2,3, ..., 719, 720. Every image that the TV camera sees is sequentially scanned from top to bottom. With 720p60, 60 complete pictures are captured and broadcast every second. And though a 720p60 HDTV set has fewer rows of pixels and fewer pixels on a row compared to a 1080i HDTV set, the 720p has the advantage of progressive scanning... it displays the entire picture in one pass, without the need to store the odd scan lines in the HDTV set, and then weave them with the even lines as they arrive. 720p60 is thus better able to display motion.
The Real World→ Now to get your feet a little wetter, ATSC digital stores and sends out the digital bits for an entire field (or frame) consecutively. Aside from just using bits, this is still very different from the way that the old NTSC analog does it. NTSC does not store anything anywhere, it does not buffer anything, and what is being sent out at any instant is what is happening in the TV camera at that instant. The difference probably is a result of the fact that MPEG-2 packaging and compression, an integral part of ATSC digital, did not exist in 1941. ("Bits" did exist in 1941... in 1936, Vannevar Bush wrote about "bits of information" that could be stored on "IBM cards" used in the mechanical computers of that time.)
1080i30, the other HD video format used for over-the-air TV transmissions, works a bit differently from 720p60→
With a 1080i30 HD video format, the images in a TV camera are scanned in two ways. First, starting at the top,
every odd line is scanned...
The whole process of "odd lines, even lines" is repeated 30 times per second. So 60 half-pictures ("fields") are transmitted each second, interlaced. The two half-pictures try to merge in our minds, and we imagine we're seeing lines 1,2,3,4,5...
It is very important to note that, in general, the image that gets the "odd line scan" is different from the image that gets the "even line scan".
(Couldn't we store the entire frame first in the camera, and then do our odd and even scans on the same frame? Well, yes... but storing a full frame and scanning it twice would require using a "frame buffer", and this double scan on the same frame is a "trick" that did not become possible until the late 1980's. Actually→ If the camera scanned faster, then there would be no need for interlacing... each frame could be scanned as "p", but this would use double the 6 MHz bandwidth. We call this double rate→ 1080p60; someday... maybe. But for now, we transmit 60 lower resolution images per second... either we send 720p60, or interlaced, 540p60, which we call→ 1080i30.)
Now, in the real world, our visual systems "snap" pictures at anywhere from 25 to 40 "snaps" per second. When things change from one snap to the next, we say, "Aha, it's moving." ("Snap" is a dog Wolf term only.)
And when we see a TV picture changing at 60 "snaps" per second, we also say "Aha, it's moving." We've been tricked. At 30 pictures per second, we often detect the trickery and we say, "Aha, it's moving, but it's flickering"... or... "Aha, it's moving, but why am I getting a migraine?"
Sixty snaps per second is exactly how the old NTSC analog TV works... 60 half-pictures per second... interlaced... 480i30, recall? And this is exactly what the "old" NTSC TVs with picture tubes expected to receive, an interlaced transmission at 480i30. The old TVs receive only 480i30, and this is all they have ever been designed to display. (The converter boxes assure that no matter what the input video format, their output will be 480i30.) OH→ But not so with the new flat panel HDTV sets.
First→ Note that with 1080i, all of the odd numbered lines reach your HDTV set before the first even numbered line is broadcast.
If a 1080i30 HD picture were displayed on an HDTV set's screen, alternating rows of pixels ("interlaced" rows) would be energized... first the odd numbered rows, and then the even numbered rows.
So now the $64 question→ Wouldn't having only half of the pixels active at any given time during a 1080i HD broadcast reduce the brightness of the screen by ½ if we had say a 720p60 HDTV set? Our set would display lines 1,3,5,7... and at any instant, half the lines on the screen would be dark. Because a 720p60 HDTV set is not designed to display an interlaced broadcast. The same for a 1080p60 HDTV set.
On the old CRT "picture tubes", we don't have this problem. In the picture tube, an electron beam hits phosphors coating the inside of the front of the tube. WHAM... A point of light forms where the beam hits the phosphors. And that point of light runs across the screen just as we read a page in a book. There is no problem with half the phosphors on the tube not working during each ½ frame. But→
The Real Story→ All flat panel screens (LCD and Plasma) are designed to be progressive, no matter what format they are receiving (and no matter what the salesman at the Big Box Store may tell you).
HUH? What does this mean?
It means that LCD and Plasma HDTV sets both draw their screens as→ Line 1, Line 2, Line 3, ... etc. They create their whole picture in one "BLAT". You don't get half-pictures (fields) displayed like on the old picture tubes; you get only whole pictures (whole frames).
So how can this be? We have 1080i30 as a lawful ATSC digital video format used to transmit HD over-the-air. You said TV broadcasts could be 720p or 1080i, dog Wolf; and 1080i is INTERLACED; that's what the "i" means, right? And the old analog 480i30 looks fine on my new LCD HDTV set, and it's interlaced, right? Right, and right... but there's more to the story.
Every flat panel HDTV set converts every incoming "i" picture to a "p" picture before it displays it. Some do it well, some not so well. Because every LCD and plasma HDTV set is going to display every frame progressively... 1,2,3,4,5... (it doesn't want to know from "interlaced"). So what happens when a 480i30 (a non-HD broadcast) or a 1080i30 (an HD broadcast) video signal comes into our flat panel HDTV?
The odd lines (field number one) first go into "memory" in the plasma or LCD HDTV, where they just sit and wait. Then the even numbered lines for the next field arrive (field number two) 1/60th of a second later, and they're added to the half-picture that's been waiting in memory. And then, and only then, the whole picture is displayed from memory (every LCD and plasma HDTV set have this memory)... lines 1,2,3,4,5... almost as if it were a genuine "p" broadcast.
Ok, so exactly how do our HDTV sets convert "i" to "p"?→
LCD and plasma flat screen HDTV sets use what engineers call a scaling processor, combined with "frame memory", to convert an incoming "i" (interlaced) picture into a "p" (progressive) display. This process of converting "i" to "p" is called de-interlacing. (Name makes sense, yes? Yes.) Here, de-interlacing is the process of converting interlaced video (a sequence of 60 fields per second) into a non-interlaced format (a sequence of 30 progressive frames per second).
The screens on LCD and plasma HDTV sets think they're getting a progressive signal every 1/30th of a second when they're receiving an interlaced broadcast; we don't tell them about 1080i30. We fool them (or we try to, anyway.) And do they fool us? The better sets do; the rest give us flickers and migraines at 30 frames/ second.
Now, let's quickly scoot back to the TV station. During the creation of the 1080i picture at the TV station, objects in front of the camera (like a football) often move between the camera capturing an image for its odd lines, and capturing an image for its even lines. And therein lies the problemo.
In other words, the two frames that are combined in our HDTV set were taken at different times, even though the different fields were created only 1/60th of a second apart. This can create a blur and/or some creative artifacts. The good news is that folks don't concentrate on details when objects are moving rapidly... if a football player is running for a touchdown, we don't care a great deal if the team logo on his helmet is a bit blurry.
Technically, there is absolutely no reason on Earth why plasma or LCD displays could not display the odd numbered lines on their screens first, and then they could display the even numbered lines next, without bothering to de-interlace anything... exactly as "picture tubes" do. And this would eliminate the flicker and the artifact associated with de-interlacing.
But this means that at any given point in time, only ½ of the pixels on the screen would be energized (the other ½ would be black); and this would halve the brightness of the HDTV set. And half the brightness is, quite simply, a "no-no" (Aussie term).
For this and other reasons (such as the lower response times of the new flat-panel technologies, LCD and plasma, compared to the older "picture tube" technology), interlaced video just does not work well with the new flat-panel HDTV sets. It works fine with the older CRT technology ("picture tubes"), so we don't need de-interlacers in our picture tube sets. But remember, they were expecting to receive 480i30.
(We're now wondering if de-interlacing is legal yet in Maryland; there may be some de-interlacing law still on the books here, dating back to the early 1600's... Ok, sorry.)
Anyway, de-interlacing is not a perfect process; it's what engineers call a "lossy" process; information is lost. We're combining two pictures taken 1/60th of a second apart, and we're pretending that they can be combined into a single whole screen picture. Will we notice the time distortion in a slow, passionate love scene? Doubtful. In an action-packed basketball game? Much more likely.
In fact, when the ATSC digital standards were being drawn up in the 1990's, there were arguments made against the
1080i broadcast format; but it's here to stay, at least for many years. (Go tell NBC and CBS and HBO, all of whom
broadcast their HD programming in 1080i, to swap out all of their new, expensive 1080i studio equipment,
including cameras, and replace it with 720p. Right.)
The Reality Of Interlaced Transmissions→ In one broadcast, any network or local TV station may flip from interlaced to progressive, back and forth. A commercial may be interlaced, the main program may be progressive. One song may be progressive, the next may be interlaced. In fact, one frame (like a congressional discussion on the economy), with a tiny picture "keyed" into it (the important LA morning daily high speed chase), may be both progressive and interlaced.
Good HDTV sets handle this chaos very well; sets of lesser quality handle it less well. The next time you have six people on the screen (Fox News) all talking at the same time about why President Obama is to blame for the extinction of the North American badger, think to yourself... "Hmmm, I wonder which of the six small pictures are "p" and which are "i"... and I hope my HDTV set doesn't catch fire from the strain of de-interlacing the right ones (the "i"'s)." (Now can you see why the old NTSC analog sets cost less? One reason is that they don't ever have to de-interlace... and everything in every frame is interlaced.)
And of course, there is no reason that a local network affiliate station cannot change the format of the "feed" that it gets from the network.
Thus, if station WQQQ (not its real name) is an ABC affiliate, and ABC feeds "Grey's Anatomy" in HD at 720p to WQQQ (which it would), WQQQ would normally broadcast "Grey's Anatomy" to its local area at 720p.
BUT... if for some reason WQQQ switches and becomes an NBC affiliate, do you think it will swap out millions of $$$ of 720p equipment, just so they can match the NBC HD standard and transmit at 1080i? WQQQ will simply take the NBC feed of say "Leno" at 1080i, "down-convert" the NBC feed to 720p, and transmit "Leno" at 720p. Works just fine.
So what's our point here?→
Our point is that sometimes it's hard to know which HD video format (including the resolution) is coming into your HDTV set over-the-air (or via cable... same thing). The only thing you can be sure of when watching an HD broadcast is this→ If your HDTV set is a 720p, then no matter what comes into it, it will display it as 720p60 (just as my PC monitor always displays 1024 × 768 at 75 frames/second).
And if your HDTV set is a 1080p plasma or LCD, it will display 1080p60 no matter which format ATSC HD (or
even analog 480i30) comes into it. (Yes, HDTV sets convert analog input automatically into digital.) HDTV sets are
accomodating and smart. Smarter every year. No battle over formats here (like the stupid new HD DVD vs Blu-ray Disc DVD
players back in 2007; but by February 2008, however, the HD DVD had gone the way of the dodo bird, the 8-track, and the
Betamax VCR; Blu-ray Disc had won). Q.E.D. (Quite easily done.)
Returning to the subject of interlacing for just another moment→ Some folks will claim that the old picture tubes (the "CRTs"... Cathode Ray Tubes) retain the two FIELDS, 1/60th of a second apart, on the phosphors that coat the picture tube screen... and that the CRT retains its picture for so long that de-interlacing isn't required... folks call this alleged retentivity effect "afterglow". Never say "afterglow"; it's a bad word.
DEEP DARK SECRET→ It's a myth (a female moth?).
The fact is that on the CRT "picture tube", fewer than 100 lines out of 480 visible lines per frame are illuminated at any instant. In other words, pictures on CRT picture tubes fade rapidly; they fade in about 1/200th of a second.
(Ever take a photograph of the screen of a CRT at 1/1000th of a second to see what's really going on? 90% of the CRT screen WILL BE dark at any given instant. But set your shutter speed at 1/30th of a second and your photo of the screen should be just fine.)
Anyway, de-interlacing (while legal) is not a perfect process. As we said, you are combining two sets of lines that were captured at slightly different times. What if, Heaven forbid, the football moves between the captures of the odd and even lines? When you combine the two sets of lines for simultaneous presentation, you will have artifact (stuff appearing on your HDTV screen that does not exist in reality, like "teeth" on the right side of the football... or even ghosts). (Think this may be why ESPN (Entertainment and Sports Programming Network) chose to broadcast in 720p60 instead of 1080i30?)
Fortunately, there are expensive and exotic ways to perform de-interlacing, and these account for a great many patents. Higher-quality HDTV sets usually have higher-quality de-interlacers, employing more complex techniques to reduce artifacts and reduce flicker.
The use of inexpensive de-interlacing hardware is a common difference between lower-priced and higher-priced flat
panel displays.
Summary→ When receiving a 1080i30 broadcast, to get all 1080 interlaced lines on a flat panel HDTV screen at the same time (progressive display), the processor in the HDTV set "weaves" together both 540-line half-frames (fields) to form a full 1080p frame. It does this by holding the first half-frame in its memory, receiving the next field, and then "knitting" the two fields together. In this process, many de-interlacers must throw out some lines and/or pixels to reduce flicker and artifact.
Now you can see why 1080i broadcasts are perhaps only 10% sharper on average than 720p, despite having more than twice as many pixels. 1080i has to throw away details during the de-interlacing process, while 720p is not interlaced, doesn't need to be de-interlaced, and thus doesn't need to throw away any details. Simple, ey?
The combined fields are displayed at once as a complete 1080p frame (or they're reduced to 720p if the HDTV set is a 720p... "We try to do what we can." -Hoke Colburn (Morgan Freeman), in Driving Miss Daisy, 1989).
Once Again Please→ Ok, let's assume that we have a Panasonic plasma 720p60 (since we do). This HDTV set can receive the old analog NTSC 480i30 just fine. So that's great, but how do we get from 480i30 to 720p60?
In three steps→
Video scalers convert video to one of many resolutions (480p30, 720p60, 1080i30, 1080p60). Scalers perform up-conversion, a process by which a video signal is taken from an "inferior format" to a "superior format"... like from component video to DVI/HDMI (remember HDMI?). Quality video scalers can make standard definition (SD) television (480i30) look cleaner and more appealing when viewed on an HDTV set's screen than when viewed on an old CRT.
Today, the term Video Processor is more common than "Video Scaler". Technically, a Video Processor covers all the possible features, such as de-interlacing, scaling, and conversion to different video formats. The Video Processor is largely responsible for the improvement that non-HD digital and NTSC analog undergo when displayed on an HDTV set.
And this is why even the old NTSC 480i30 broadcasts and other non-HD video signals generally look better on the new
HDTV displays. (And the improved video quality of LCD and plasma, and the big 16:9 screens don't hurt either.)
Digital TV broadcasts a series of bits. Since digits rather than a waveform are broadcast, digital allows near perfect transmission. But "near perfect" comes at the expense of bandwidth; digital requires more bandwidth than analog. But the FCC said, "Bandwidth is dollars; thou shalt use the same 6 MHz channels for digital. So the only solution was to compress the digital signal, compress it vigorously. This compression was accomplished by using MPEG-2.
Ever see an HD camera working away in some TV studio? No? We haven't either, at least not live and up close. But we do know that studio HD TV cameras produce a raw video stream in excess of one billion bits per second. A billion bits per second→ Yeeks. If the picture from an HD camera is ever going to fit in the skinny 6 MHz broadcast channel assigned by the FCC, first something dramatic has to be done here.
That "something dramatic" that the ATSC digital standards require is called MPEG-2 Compression, which occurs in the Video Subsystem at the TV station. In a nutshell, MPEG-2 is the process that ATSC digital TV uses to convert the images in the TV camera from a torrential bit stream into neat rows of tiny data packets... achieving massive compression in the process. (We'll dissect MPEG-2 in more detail in a bit.)
Don't Be Confused→ MPEG-2 is the ATSC standard for compressing digital television signals prior to 8-VSB modulation (in the "exciter") and broadcast from the antenna atop the TV tower.
Cable and satellite providers add additional compression on top of studio MPEG-2, which is also "lossy". Lossy means that when you decode the additional compression added to over-the-air broadcasts by cable and satellite providers→
Note→ Many cable providers and most satellite providers are currently using a newer collection of compression methods called MPEG-4. This MPEG-4 compression is stacked on top of the MPEG-2 compression applied at the TV station. MPEG-4 is a ten year old set of standards; it's up to each provider to decide exactly which compression standards he wants to employ.
FiOS→ FiOS adds no additional compression to HD programs.
SO... In sending ATSC digital TV over cable and satellite, a TV signal whose picture is already MPEG-2 compressed (and whose Dolby sound is already AC-3 compressed), is further compressed by non-standard, non-ATSC, cable and satellite techniques. FiOS is not further compressed; and this is why over-the-air and FiOS programs look (and sound) better than cable or satellite.
Using ATSC Digital Standards (A/53), an ordinary 6 MHz TV channel can broadcast over-the-air at up to 19.39 million bits/second of video and sound and data. And before we actually modulate (legal in Maryland) and broadcast over-the-air, we add a lot more bits, mainly for "forward error correction". We thus end up transmitting well over 30 million bits/second; but 19.39 MBit/sec is the bit rate limit that can exit our Service Multiplex, the guy who combines our compressed video and our compressed audio plus a little ancillary and control data.
So some of that 19.39 million bits/second must be subtracted for sound (recall Dolby?) plus other non-video data. This leaves about 18 million bits/second for the HD picture, the video, with a format of either 720p60 or 1080i30.
SO... MPEG-2 compression has to take us from way over a billion bits per second to under 20 million bits per second. That's better than a 50:1 squeeze. So what is this MPEG-2 anyway?
What'S MPEG-2→ (Impress Your Saturday Night Date→ "MPEG" stands for "Motion Pictures Experts
Group".) MPEG-2 is the "packaging" format for the streams of bits and bytes in a digital television signal. MPEG-2, in
this capacity, is also the standard for video compression that's specified in the ATSC Digital Standards. (MPEG-2
also was a contender for the ATSC digital audio compression techniques, but it lost that battle to AC-3
compression; AC-3 is Dolby Digital.)
MPEG-2 typically can squeeze a billion bits/ second all the way down to 20 million bits/second. MPEG-2 uses several cool tricks to achieve this feat; one trick is to make sure that anything in the picture that has not changed since the last frame is not re-broadcast. A cowboy rides through our picture under a big blue sky, the sky doesn't change, MPEG-2 says "Do not rebroadcast the sky".
And there are things in the picture we can throw out, things that folks will never even notice.
HUH?
Never even notice? We notice everything... uh, don't we?
Nope, and that's what makes possible the "thinning out" process that MPEG-2 uses. Every pixel coming from an HD TV camera is associated with three numbers... one for the brightness, two for the color. (To be overly technical for a moment, these three numbers are the three axes for a "color space". Given brightness and the two color numbers, we can locate a unique color.) But can we really observe and detect and discern the color of each and every pixel? No way, José.
So MPEG-2 compression may throw out perhaps half of the color values. Let the pixels without color values be the same color as their nearest neighbors. We don't notice this trickery because our eyes are more sensitive to brightness than to color. (Like, trichromatic color was added to human vision as "icing on the cake"... most mammals get by with dichromatic color vision... though some life-forms (yes, on Earth) see with "cone" nerve cells that have a peak response to as many as twenty colors; fortunately, these life-forms, like a species of shrimp, rarely watch color TV.) But for any given pixel, nearby pixels tend to be the same color or a similar color.
In HD, we end up with about 270 rows containing color, out of a total of 720 or 1080 rows. In analog, we have 120 lines with color, out of 480 total lines. Who would ever have guessed?
MPEG-2 compression uses the notation 4:2:2 to mean that half of the color values have been deleted. And the notation 4:2:0 says that three-quarters of the color values of the pixels have been deleted. (If no color information has been deleted, the notation is 4:4:4.) MPEG-2 compression permits all three of these options, take your pick. 720p60 and 1080i30 both use 4:2:0 (meaning three-quarters of the pixel color information is thrown out the window). ¿Está claro?
How else does MPEG-2 compress, besides throwing away a lot of color information and not re-transmitting the same stuff? Here are three additional techniques that are employed in digital broadcasting's MPEG-2 compression→
But as always, there are no free lunches; well, hardly ever. MPEG-2 is a "lossy" compression technique, meaning that
the more you compress a TV picture before broadcasting it, the poorer the picture's quality when it's received and
expanded again. In other words, there's a loss in picture quality between the HD TV camera and what appears on your
HDTV set... but nothing too serious. MPEG-2 is relatively "gentle".
Now... why can't we use compression to broadcast 1080p (1080p60)?
Well, HD at 1080p60 generates twice the bit rate of 720p or 1080i; namely, it needs to transmit at about 36 million bits/ second. And the ATSC Digital Standards for over-the-air broadcasting do not permit such a high bit rate in a 6 MHz TV channel... neither does current engineering technology.
OK, let's look to cable for possible relief... a 6 MHz digital cable channel can accomodate 38.78 Mbps, using 256-QAM modulation (we'll explain that). And so a 6 MHz digital cable channel can carry 1080p60 video... well, in theory, at least.
Will cable providers send 1080p60 video to our homes? There presently are no announced plans for such a "treat". Cable providers are having enough trouble finding the bandwidth that they need to carry 720p60 and 1080i30 HD broadcasts, without worrying about "treats". (Will FiOS ever carry 1080p60? Stay tuned.) The new Blu-ray Disc DVDs can inject your 1080p HDTV set with HD at 1080p60, and it looks good.
The Real Story→ For strange and scary reasons (in other words, for "engineering" reasons), progressively scanned images ("p") compress better than interlaced images ("i"). At the TV studio, the "raw" data coming from an HD TV camera pours out, usually at 1.485 billion bits per second.
And just to review briefly→ Data from an HD TV camera is compressed down from its high data rate so that it will fit in a 6 MHz channel. The whole picture plus possibly the Dolby 5.1 sound plus ancillary and control data has to use no more than 19.39 million bits per second... the digital over-the-air capacity of a 6 MHz broadcast channel.
Well, this looks better and better→ Since "p" compresses better than "i", and 1080p60 is "p", and 1080p60 generates twice the data flow from the TV camera compared to 720p or 1080i, we might expect that 1080p60 would fit nicely in a cable channel that can hold 38.78 million bits per second.
Well, yes, it does fit. But it does not look good on an HDTV screen after its compression. Compression produces artifact, and compressing 1080p60 from about three billion bits per second in the TV studio down to 38 million bits/second simply produces too much artifact, at the limits of current technology. The picture looks worse than Standard Definition (SD). It looks awful.
Technology continues to improve, but it's far more likely that broadcasters will continue compressing 720p60 and
1080i30, so that they can squeeze more "other stuff" into a broadcast (or cable) channel. (But will FiOS carry
non-Broadcast programming (e.g., HBO HD) at 1080p60? Will your HDTV set handle this? Will the FiOS fibers go up in
flames? Stay tuned.)
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OK... Time now at last to peek deeper into exactly how digital TV is actually broadcast from the antennas atop TV towers to the antennas connected to our TV sets and converter boxes, to the cable providers, even to the satellite companies and to FiOS, to whomever.
We began this article by blowing the trumpets and conveying the proclamation of the US Congress abolishing full-power analog TV after 12 June 2009, and allowing after that momentous date only the full-power broadcast of digital TV. (Not counting 30 days of analog nightlight.) Now the time has arrived to explore just exactly what the difference is between analog things and digital things...
(Pay attention, this is good stuff; many folks (including even a few computer science professors) muck it up (threw in an Aussie-ism there).)
Digital things have dis-continuous discrete states (they have different values that you can't move between smoothly and continuously). Whoop. So just what does that mean? We're converting to digital TV in June so that we can have "discrete states"? (Most folks come up with Alaska when they're asked to name a discrete state.)
OK... The pole lamp in DAwn's bedroom has three (energy-saving) bulbs. It can be in one of FOUR possible states... all three bulbs off, only bulb #1 on, only bulbs #2 and #3 on, or all three bulbs on... dark, romantic, normal, or bright. It does not continuously move from, say, #1 on to #2 and #3 on. It's blat; instantaneous. DAwn's pole lamp will be in one of four possible discrete states at any time that we may "sample" it. Anything else is an error; e.g., only #1 and #2 on indicates that there is an error somewhere... maybe a short circuit, who knows? (Maybe we had one too many beers.)
Things like DAwn's pole lamp that have a finite number of states (a countable number... a number that you actually can count up to, if we give you enough time) are called DIGITAL. DAwn's pole lamp is digital; it only has four states, we can count to four, four is a finite number. And at any point in time, the lamp always will be in one of these four states. And the lamp does not move continuously between states; it's blat... #1 on, then #2 and #3 on... blat. The word digital comes from digitus, the Latin word for finger; digital things have countable states, and fingers are used for discrete counting.
Ok, great... another example...
Any of the THREE Giant FoodMarts in this area is, at any time we sample them, open or closed; they each can be in two
discrete states, open and closed; and in this area, the three Giant stores taken together are thus in one of EIGHT possible
states
The light in the bathroom off of DAwn's bedroom has only two states; it's either on or it's off at any sample time. It is not only DIGITAL (because it has a finite number of discrete states, two), it's also BINARY. Why? Digital things with two discrete states are called binary. And a bit is binary... it's either a "0" or it's a "1". If the bathroom light went slowly from off to maximum when we flipped the switch, it would be analog; but you flip the switch and blat... the bulb instantly comes on at maximum brightness... it's definitely digital.
DAwn says that LOVE is binary ("He loves me, he loves me not."). The circuits in PCs and digital TV stations are almost entirely binary... their voltages tend to be in one of two states at any time, ON or OFF... or some two voltage values that represent on and off. Binary electronic circuits are VERY cheap to build. DAwn also has an old TV in her bedroom; the TV is either on or off; thus it is "digital". DAwn cannot understand why her old bedroom TV cannot receive the new digital channels, if it is a "digital" TV. (Ok, sorry.)
Returning to DAwn's bedroom, DAwn loves to read, and she has a reading lamp with a dimmer. Because of the dimmer, the lamp has MANY, MANY states, MANY MANY brightness levels, and we move between these levels continuously. "How many states?" you ask your dog Wolf. A LOT. In fact, in theory (if we ignore "noise" and "quantum level uncertainty in measurement"), it has an endless number of states, an INFINITE (∞) number of states, more possible states than we can ever count, no matter how much time we may have. (The dimmer/lamp actually has as many states as there are integers, but it does not have as many states as there are irrational numbers; trust us on this.)
Things which can be in an infinite number of possible states at any given sample time are called ANALOG. They have a continuous range of values. Like, the temperature out on DAwn's back deck is analog... it has a great many possibilities, a great many possible values, more than we can count, no matter how much time we may be given. And the temperature moves continuously between any two points... like when it goes from 32ºF.→33ºF., it hits every possible rational intermediate number; it hits an infinite number of intermediate temperatures.
Yet another example. DAwn has a digital thermometer out on her back deck; it transmits the temperature to a small LCD screen on her bedside table... 29.8, 29.9, and so on. There are a lot of possible temperature readings, especially when you include tenths, but there are a countable number. And so the thermometer readout system is digital. But at DAwn's foyer is a barometer with a pointer; it goes from 29 to 31 inches of atmospheric pressure. But to get from one pressure to another, the pointer must sweep across an endless number of intermediate pressures continuously; "infinite states" light up the analog flag in our minds; the barometer must be analog.
DAwn's weight is analog. (Whoa... we're not saying here that HER WEIGHT is infinite, just that it can be in an infinite number of states... 107.02 lbs, 107.101 lbs, 107.1123 lbs, etc. (DAwn is actually exponentially distributed.) )
But, when DAwn stands on her digital scale however, the scale displays some "digits" from 0 to 300. The display
on the scale thus will be in one of 301 discrete states... 000, 001, ..., 299, 300. Thus, the scale is digital. This scale
is an example of an analog to digital converter... it converts Dawn's analog weight (which can have a great many values)
to a display that is digital (it can have only 301 values). Great.
And Just A Little Bit More→ Things that are digital always can be represented by a finite string of bits (0's and 1's). The string may be long, but it eventually will come to an end. BUT... Things that are analog cannot be accurately represented by a finite string of bits, no matter how long we may make that string. Things that are analog can only be approximated by bit strings.
The TV signal coming from a digital TV station over a period of one second can be represented by a string of
about 30 million bits. The TV signal coming from an analog TV station over a period of one second cannot
be represented by a string of bits of any finite length. (Yes, it may be approximated by a string of bits, but it
cannot be precisely represented.)
Dog Wolf Totally Out On A Tangent→ One of our readers wrote to us, wondering whether the Universe is analog or digital; and if the entire Universe is digital, then why do we have to convert TV transmissions to digital in June, near the beginning of summer? Because then the Universe and everything inside it would already be digital and... and we see their point.
Dr. Steve→ “Because any chunk of our Universe can be only in a finite number of discrete (quantum) states (when things start to get really small); and since our Universe appears to be about 90 billion light years across, and a finite number × a finite number ≈ a finite number, the Universe is thus digital. (You cannot move continuously between very tiny things in very tiny states in our universe.)”
DAwn→ “I almost never disagree with Dr. Steve; but my undergrad majors were math and physics. And so I think that in looking at the question of "Is The Universe Analog Or Digital?", we might need to take into account Gödel's** two incompleteness theorems (and possibly also Turing's** theorem). In particular, we should look at the recent proof by David H. Wolpert at NASA, which states→ Within any system of universes, quantities exist which cannot be ascertained by any inference device (including people) inside the system. And it just may be that whether the universe is analog or digital is one of these inherently unknowable quantities.”
Best we leave it at that.
(** Gödel #1→ Any effectively generated theory capable of expressing elementary arithmetic cannot be both consistent and complete. In particular, for any consistent, effectively generated formal theory that proves certain basic arithmetic truths, there is an arithmetical statement that is true, but not provable in the theory.
** Gödel #2→ For any formal recursively enumerable (i.e., effectively generated) theory T including basic arithmetical truths and also certain truths about formal provability, T includes a statement of its own consistency if and only if T is inconsistent.
(** In other words→ Within any formal mathematical system advanced enough to be of any use, it is impossible to use the system to prove every true statement that it contains.)
** Turing→ One cannot, in general, determine if a computer algorithm is ever going to halt.)
End of our total tangent. ♣
SIMILARITIES→ After all the hoopla about going from analog to digital settles into the cosmic dust, we realize that ATSC digital is really very similar to NTSC analog. Both are sent from TV transmitters over-the-air to TV receivers, sent by electromagnetic waves that are created in the TV transmitter. And in both the cases, the information that we want to send is used to "low band modulate" the electromagnetic carrier waves. When you get right down to the physics of the things, both analog and digital TV are similar to the commercial AM radio that sprang up in the spring of 1922. And most fundamentally, though the digital picture may be a bit better, it does nothing for the programming (e.g., The Bachlorette); programming will be just as bad with digital.
Dr. Steve believes that one day not too far away, perhaps by 2075 or 2100, we'll be using quantum qubit-based transmissions (Verschränkung (entanglement) ), also known as non-local stuff. The quantum TV transmission, of course, will be instantanous; no more "slow" broadcasts barely moving at the speed of light; I mean if you were a sponsor, maybe you'd like SuperBowl CXLIV advertised across the Alpha Centauri solar system... well, instantly. And surely we'd want to broadcast to the entire, almost infinite, mostly independent, parallel universes all about us (in spite of a few initial problems with "quantum decoherence" prior to 2115).
Dr. Steve believes that most intelligent life goes through perhaps 100-200 years of electromagnetic wave communication,
replete with modulation and sidebands, before they move into far more advanced techniques, such as qubits. And for this
reason, our search of the skies for modulated electromagnetic waves from intelligent alien civilizations never can bear
fruit. Of course, using quantum bits and non-locality, it gets a little "through the looking glass darkly" when you
turn on your TV, only to see yourself turning on your TV, only to see...
Analog TV VS Digital TV→ So now let's just get our toes wet here... on this hot, hot day in the cool, cool ocean... with some simplified explanations, now that we have an idea of which things are analog and which are digital. At a TV station, a program starts by focusing a television camera on something. The camera changes the brightness and color of the scene into an electrical video signal... that is, the light image in the TV camera is changed into an electrical image on a "target"; this electrical image is "read" from the back of the target by an electron beam, which scans the image.
With analog TV, as the camera scans the image, the video signal from the camera varies, depending on the brightness and color of each point in the scene. When the electron beam in the camera hits a bright spot in the image, the camera emits a high voltage; hit a dim spot, you get a lower voltage. This video voltage is sent through cables at the TV station to the TV transmitter, which broadcasts the video signal to our TV set.
At any instant in time, the signal being sent by the analog transmitter represents the brightness and color being
scanned inside the camera. After the transmission is received by our analog TV set, one or more electron beams in the set
are used to recreate the original image on our set's picture tube. In theory, the video signal broadcast from the TV
station can have ANY value between white and black... it's analog... it has many, many discrete states. And the
brightness and color of the
With digital TV, the video signal that is produced by scanning an image is converted into binary numbers; most digital signals are generated at up to 1.5 BILLION bits per second. This video signal is then compressed. The sound, also a string of bits, is likewise compressed; the video and sound bit streams (and other stuff) are then mixed together. This combined bit stream eventually reaches the digital transmitter.
The digital TV transmitter sends out a bit stream representing the picture, the sound, and other stuff roughly ten
million times each second, each time as a string of just 3-bits (eight different values, recall?). Our digital TV
receiver samples the signal from the transmitter ten million times per second, and it expects to get one of eight discrete
values... after all, it is digital. And moreover, the picture ultimately displayed on our home digital TV screen is
NOT in sync with the picture in the camera... there is buffering, and picture and sound lag a little behind
reality. (Much more on all this coming up.)
OK... Since 1946, millions of us have been receiving analog broadcasts through our TV antennas from antennas on several thousand TV towers spread across the US landscape, some on top of skyscrapers serving bustling cities, some 2,000 feet high self-supporting on the prairies and the plains serving entire states. And most parts of the TV waveform transmitted from these analog TV stations and towers were varying in a continuous fashion, signals taking on a great many values, more values than we could count.
Introduction→ They never tell you much about how digital transmissions actually differ from the old analog transmissions. The analog signals radiating from transmission antennas high up on TV towers are quite different from the newer digital signals. The signal voltage broadcast from an analog antenna is wavelike. And theoretically, ignoring quantum effects and noise, there are an infinite number of values that the analog wave leaving the TV antenna on the tower can assume, anywhere from 0 to some maximum amplitude.
On the other hand, a digital transmission is based on a digital format, based on strings of ones and zeros (bits). The digital signal cannot have an infinite number of values; in fact, it can have eight discrete values. Eight values are represented by 3-bits, recall?
NTSC Analog→ Video carriers being VSB modulated (a type of AM modulation), color carriers being quadrature modulated before they are suppressed, sound carriers being frquency modulated... and all analog. And we care about their values continuously; we don't simply sample the signal from the analog TV station at 10.7 million times per second... we feed those signals through circuits directly to our analog TV set's picture tube and speakers continuously.
In an analog TV transmission, "very" small changes in the picture part of the signal, intentional or unintentional, will change the picture on our analog TV sets. Maybe the grass will turn blue (unintentional)... maybe bursts of "snow" will interfere with the game-winning touchdown (unintentional, unless the game is being played in a blizzard, as happens sometimes)... and so on.
And on the other hand, the components of an ATSC digital broadcast are represented by just three bits, representing eight "symbols", 10,760,000 of these "trellis numbers" broadcast each second... three bits that must be sampled at just the right time in our new digital receivers. In the digital world, there are no analog dimmers.
ATSC has decided that the TV signal can have precisely eight discrete values at a very precise sampling time. (Between
these 11 million sampling times each second, we have noise; don't really care who lives there... maybe there are
inter-dimensional parasites, who cares?) And if we get something other than one of these eight values when we sample, we
may take a guess at what the value should have been, as long as we're not too far off the mark; or perhaps we'll
let the digital TV station realize that it has made an error, and we'll let it retransmit a little bit of the
digital signal.
Analog broadcasts are like the old, obsolete (but often valuable) vinyl records... the single groove on these records varied continuously, they were ANALOG records. In Analog TV Broadcasts, the frequencies received by our analog TV sets have been varying continuously, the amplitudes have been varying continuously, the phases have been varying continuously... virtually anything that can vary has been varying Continuously... and any value is legitimate... our analog sets can't tell snow (interference) from snow (during the weather forecast).
And that's been analog TV for 60+ years, since TV really started to get cranked up around 1946. WWII has ended, it's 1946, time to get started with the analog TV that we standardized back in March of 1941, and that the FCC approved in May of 1941.
(We don't think we really thought of it as "Analog TV" until Digital TV poked its snoot up a few decades later.)
Another way to think of digital is that digital TV is sent out as 1's and 0's, yes's and no's (right, as BITS)... just like the digital data flowing through our PCs... not as a continuously varying analog signal. He loves me, he loves me not... on or off... take it or leave it... that's Digital.. 10,760,000 of these "trellis numbers" per second, each three bits long, each in one of eight possible states, each representing one of eight possible "symbols". Discrete. Finite.
Quick Review Of Digital Bandwidth→ All digital information is a series of 0's and 1's (bits). The more zeros and ones broadcast per second, the higher the data rate; the maximum for a digital broadcast in the US is a data rate of 19.39 million bits per second coming from the multiplexer, going into the "exciter"; and after forward correction bits and what-not are added, perhaps 32 million bits per second flying off the antenna atop the TV tower, in its assigned 6 MHz digital channel.
In digital TV studios (those that prepare programs that are broadcast digitally), prior to compression by MPEG-2, High Definition data is routed around at about at 1.485 Billion Bits per Second. See the need for compression? See how powerful compression like MPEG-2 (55:1 compression) can be... using digital data? Digital TV takes up more bandwidth than analog, but it compresses better.
CDs and DVDs are digital; they don't have a single varying groove like analog vinyl records did; instead, they're chock full of millions of 0's and 1's. That's Digital TV... millions and millions of 0's and 1's flying away from the TV broadcast antennas to your TV antenna (rooftop, rabit-ears, cable provider, whatever) every second. Digital TV serves up its digital TV steaks the same way that your PC does... with 0's and 1's. (Getting hungry here.)
(Clarification→ The TV broadcast tower raises the TV broadcast antenna as high as possible (without interfering with other antennas that may be sharing the tower). The objective is to get that piece of metal, the TV broadcast antenna, up as high as possible. The higher up you get it, the farther it's signal will travel (in general). The tower itself is just there to get that piece of metal, the antenna, up as high as possible. The tower doesn't broadcast anything. AM radio towers, on the other hand, broadcast from top to bottom→ the entire commercial AM radio tower is the antenna.)
Ok... digital TV broadcasts are sent out from the TV antenna at a maximum data rate (video, audio, and ancillary
data) of 19.39 Mbps... just under 20 million 0's and 1's per second... plus at least another 12 million bits per second
for error correction and "pilot signals" and other stuff. (And would you believe that about 38 Mbps of video and audio
and data can fit in a 6 MHz analog cable TV channel?) But we're getting ahead of ourselves here... as in, take
two time capsules and call me yesterday morning. Ok, sorry, we know... Reed-Solomon encoders and such are a serious matter.
Stated Another Way→ The conversion to digital-only is changing the language that TV transmitters use to speak to your television. Since about 1946, US TV stations have transmitted using standards laid out by the NTSC in 1941. Big TV towers (get that antenna up there as high as possible) transmitted pictures and sound over-the-air speaking the NTSC language; these transmissions were received by the little antenna on your TV set. And inside your TV, there was of course an NTSC tuner, converting analog broadcasts to analog pictures and analog sound.
The mid-June conversion to digital-only will fill the ether with a new language, new standards designed by the ATSC. All of those broadcast stations, the ones categorized as "US full-power", will no longer be speaking NTSC; instead, they'll be speaking ONLY ATSC. Sadly, your old analog TV can't translate the new ATSC into pictures and sound. BUT... Almost all TVs sold in the US after March 2007 have ATSC tuners. Sets bought before that probably have no ATSC tuner.
The Answer→ A converter box, not much more than an ATSC tuner sitting between your antenna and your old NTSC
TV set. The ATSC digital signals reach your antenna, then are passed to the converter box that translates the ATSC signals
into the old familiar NTSC language. Of course, in the whole process, one or more of your favorite analog stations may
forever disappear; a more potent antenna sitting on your roof may help; or not.
According to the National Association of Broadcasters (NAB), as of November 2007 there were 1,625 TV stations in the US broadcasting digital signals; this was about 92% of the roughly 1,749 full-power TV stations transmitting in the US.
A LITTLE PERSPECTIVE→ When things are quiet, using Comcast Cable to access the Net, we can download files at up to 18 million bits/ second... in fact, at the present, 437 AM EDT, let us see what our download speed is from, say, New York City (just our curiosity)...
Ok... 17.778 Mbps it be; so digital TV radiates from the TV broadcast antenna to your digital TV receiver (and to cable and satellite broadcast centers) just a little bit faster than our late night download speed from New York City ... but every bit as digital.
NOW... How long before we can download HD TV broadcasts from WQQQ (no, not his real name) on the NET using our PCs,
then feed that data over to a big HDTV set IN REAL TIME? Ah, you blinked; we already have IPTV. What, you can subscribe
to movies and such from Netflix via the Net? In December 2008? Ah, you blinked once again. But stay tuned.
Until a time of the station's choosing on 12 June 2009, the biggest full-power TV stations in the biggest cities in the US were broadcasting on two channels... you could watch the channel you preferred on your new HDTV set. The second channel was a free gift from the FCC to allow stations to debug their digital transmissions, and the stations held these for roughly a decade. Most of these second channels lived on vacant UHF channels (but not all).
One of these two channels was the the old analog channel, sending out the old analog broadcast signal approved in 1941... and by 1946 televisions are beginning to appear everywhere, even with regularly scheduled analog broadcasts... for as late in the evening as they could keep the TV transmitter running... sometimes even past midnight... and then the National Anthem playing and the video of an American flag and finally signoff and test pattern and snow... and then the beginning of TV networks... and a TV station in every city... modified only slightly since those early days, still very analog, even after color and stereo sound were added... this analog channel of the two was our "old vinyl record", the first channel... nostalgia.
And then there came a second, newer channel, first assigned in 1996... a new digital channel... a 10-year temporary channel... well, temporary in most cases. Our "CD" channel. On a temporary channel, often running at a fraction of its future digital-only power to save the broadcaster's electricity... mainly there just so the broadcaster could test digital TV equipment and code and HD.
Careful→ In magazine, newspaper, Web, etc articles, it was often mistakenly stated that the second, temporary digital channel was a UHF channel; i.e., some TV channel between 14 and 69. NO. It was often UHF, but not always. Thus WBBM in Chicago broadcast in analog on channel 2 and in digital on channel 3. WBPH in Philadelphia was broadcasting in analog on channel 60 and in digital on channel 9. Nota bene.
And where is the digital TV station of the pair broadcasting now after 12 June? In early August of 2007, the FCC issued final digital channel assignments for almost every US TV station. Some stations continued broadcasting in digital on their "temporary" digital channel (temporary became permanent).
Other stations are broadcasting in digital where their old analog channel used to live. And a small percentage will got a completely new channel for their digital broadcasts. Any TV station with a temporary digital channel above 51 had to move its digital transmission to some channel in the 2-51 range (the so-called "core" TV spectrum), since channels 52-69 will no longer belong to TV. Chaos in the making, ey? Let's examine things locally here, in the Baltimore area.
WJZ-TV was broadcasting in digital on channel 38. WMAR-TV was broadcasting in digital on channel 52; but WMAR-TV's final channel assignment was 38. Boing. WMAR only could get to its final channel After WJZ vacated its temporary digital channel, channel 38.
If WJZ had had a problem (like perhaps some supplier ran out of filters before it could ship one to WJZ), that would have forced WMAR to stay on channel 52. But channel 52 already was sold at auction. It's not a television channel. Plus there might have been another station in the area that would start getting interference if WMAR kept broadcasting in digital on channel 52.
This "final channel" thing could have gotten Very complicated. Folks simply said, "We have to be alert on this."
Few folks said what we were thinking... though many were thinking what we were saying→ "We've painted ourselves
into the worst possible kind of a very tight and very tiny corner." Chaos in the making, ey? These were surely exciting
times in which to be alive. And somehow, the game of musical channels actually worked out.
| STATION | LOCATION | ANALOG CHANNEL |
TEMPORARY DIGITAL CHANNEL |
FINAL DIGITAL CHANNEL |
| WCAX | Burlington, VT | 3 | 53 | 22 |
| WPIX | NY, NY | 11 | 33 | 11 |
| KVEA | Corona, CA | 52 | 39 | 39 |
We were curious about exactly how TV stations in our local area were handling the transition to digital. And we were certain that we could illustrate some sexy new aspects of Digital TV at the same time that we were satisfying our curiosity. We pressed Precise Networking Solutions' professionals (folks with First Class Radio-Telephone Licenses, guys who previously worked at TV stations) for the answers, and they came up with this for us→
In this area, NBC affiliate WBAL still broadcast its old analog TV signal on channel 11, just as it had done since March of 1948. It transmitted in analog from a tower about 1,300 feet above sea level, and it nicely covered the Baltimore Metro area and the Washington, DC, suburbs in Maryland, even reaching into southern Pennsylvania. Since December of 1999, WBAL had also broadcast virtually identical programming in digital on a new channel, previously unused in this locale→ UHF CHANNEL 59. From time to time, there was an HD broadcast on channel 59, like The Today Show and Leno (and beginning 4 January 2009, the local news).
Before 12 June 2009 ended, WBAL digital moved from temporary channel 59 down to channel 11... where its analog transmitter previously had been broadcasting.
WBAL ANALOG→ Channel 11→ (12 June 2009 comes and
goes) → No More Analog.WBAL DIGITAL→ Channel 59→ (12 June 2009 comes and
goes) → WBAL Digital moves to channel 11.WBAL's digital channel 59 also broadcast A Second Program, "Insta-Weather Plus", the weather, continuously.
SURPRISE→ You can fit more than one program into one 6 MHz digital channel. And with a digital TV set, you can select which "sub-channel" you want to watch from digital channel 59... Leno or The Weather. (We've hinted at this previously; it's called "Multicasting".)
You see, channel 59 is digital, just like your PC. And your PC can download more than one thing at a time. So we might expect that digital TV channels can carry more than one program at a time. (We know, it's not a rigorous argument; but it may give you a taste of what's going on in a digital TV facility, from the camera (or tape machine) to the transmission antenna.)
The primary digital progam is designated with a "-1" after the channel number, the next program with a "-2", and so on, up to a maximum of about "-5" or "-6". So if we want the weather, we enter "59-2" into our digital TV, if we're receiving TV broadcasts over-the-air. 59 is called the major channel number, and subchannel 2 is called the minor channel number. The major channel number specifies the 6 MHz frequency band for over-the-air broadcasts. (Makes sense, yes?)
