Look how the video is sandwiched between the video carrier and audio carrier.
Posted on 12/02/2005 1:35:43 PM PST by nickcarraway
Zoran, a little-known chip company in Sunnyvale, is providing a big service to Silicon Valley by smoothing the long and bumpy road from analog to digital television.
In about three years, all the familiar analog VHF and UHF channels -- such as 2, 5, 7, 9, 11, 36 and 44 in the Bay Area -- will go away and the stations now at those numbers will be available only on digital channels. That's potentially a big problem for the estimated 15 million households who get their television over the air through rabbit ears or roof antennas.
Those folks won't be able to receive these, or any, digital channels over the air on a regular TV set without the addition of a converter box. And if that converter box is too expensive on the day VHF and UHF die, millions of citizens suddenly deprived of ``Jeopardy'' and ``Lost'' could riot in the streets.
Zoran is easing the potential pain with a new chip called the SupraHD 640 and related software that should make it possible to sell converter boxes for $50 when the transition happens -- far below the $200 to $300 cost of converters today.
Last month, the Senate set a deadline of April 7, 2009, for the analog shutdown. The date was picked because it's just after the college basketball Final Four, and there are apparently a lot of basketball fans among our elected leaders. Earlier, the House set a date of Dec. 31, 2008.
The House and Senate are expected to resolve their timing differences before the end of December, settling on a single date. And they'll compromise on the amount of money to spend on a program to subsidize the cost of converters. The House now wants to allocate about $1 billion for subsidies, while the Senate is looking at $3 billion. The subsidy programs could ultimately offer $40 a converter, so the final cost to consumers in early 2009 might be only $10 for each box.
Most of the 110 million U.S. households with TVs have nothing to worry about.
If you get TV through a cable or satellite set-top box, that box will convert digital signals for viewing on your regular, non-HD set. If you get cable service without a set-top box, by plugging your TV directly into a cable jack, your cable operator will probably come up with a solution. You'll either get a set-top box or the cable system will convert digital signals to analog before they reach your house.
But an estimated 15 million households, about 14 percent of the total, get their TV the old-fashioned way: over the air from local TV broadcasting towers. These are the people who will need converters.
There are also mixed households, with a TV in the living room that's attached to cable or satellite, but a second TV in a bedroom or kitchen that's only receiving channels over the air. These second TVs will also need converters.
Eventually, converters won't be needed at all. The Federal Communications Commission last year ordered TV manufacturers to start putting digital tuners into TV sets. By the end of 2007, all new TVs will be capable of receiving digital over-the-air broadcasts. As older non-digital TVs are junked, demand for converters will shrivel -- although it's likely to be many years before every last analog TV disappears.
Congress desperately wants to make this transition happen, if only because the vacated analog TV channels will be auctioned by the federal government for an estimated $30 billion -- a significant cash infusion in this era of soaring deficits.
Silicon Valley also has a big stake in the transition because the frequencies are likely to be used for advanced wireless services that will create lots of demand for new hardware and software.
Meanwhile, Zoran took an important step forward Monday by announcing a ``reference design,'' a kind of blueprint, for using its SupraHD 640 chip to build low-cost converters.
David Pederson, Zoran's vice president of corporate marketing, said Tuesday that the reference design should make it possible for manufacturers to start producing and selling converter boxes in the second half of next year for under $100, with the price dropping to $50 by late 2008 as Zoran develops even more efficient and inexpensive chips.
The SupraHD 640 can also be used to add low-cost digital reception to TVs. Instead of boosting the cost of TVs by about $300, what it now costs to include digital, Pederson estimates the price increase will be $40 in 2007 and just $20 to $30 by late 2008.
So chip companies such as Zoran and its competitors, including ATI Technologies of Markham, Ontario, get to sell millions of digital video chips for TVs and converters. TV manufacturers get to sell the sizzle of digital -- digital broadcasts look much better than analog even after conversion for viewing on non-high definition TVs, somewhat like the difference between DVDs and VHS tapes. The sound, too, is superior.
Pederson concluded, probably without much exaggeration: ``Nobody loses in this deal.''
If you're watching it on an HDTV, you're right, it can be pretty bad sometime, but down-rezzed to SDTV resolution, it should look pretty good. I know recently when I was between HDTV sets I was using the 480i ouput of my HD cable tuner box to watch HD channels, and they looked really good, as good as the premium digital SD channels.
Given the amount of logic required to uncompress digital video, how hard would have been to allow any resolution up to 2048, and any frame rate up to 60 (or even 120) and let television sets deal with it as they see fit? Would it cost significantly more to produce a receiver that could convert a 2400x1800@72 image down to NTSC than to make that was restricted to 1080i resolution?
It seems to me that for viewing movies, 24fps is better than 30fps (and raster-scan sets could display it as either 72 frames/sec progressive, 24 frames/sec with 3:1 interlacing, or 48 frames/sec with 2:1 interlacing). Was/is there any reason not to allow broadcast in whatever format best describes the source data?
The answer lies in the 60 Hz AC line. The 30 frames per second / 60 fields per second was selected to avoid having a heterodyne beat causing a moving dark band across the screen. The chroma subcarrier value was constrained to work with the frame rate/line rate.
The ATSC standard does include a 1080p24 setting, I believe. Certainly it is widely used in digital movie cameras and post-production work. Actually, the same 2-3 pulldown trick that turns interlaced NTSC video from movies on DVD back into progressive scan frames works for 1080i, also. However, as you say, it also requires turning 24 fps into 30 fps, which is also problematic. CRT televisions would not work well at 24 fps, and the ATSC standards that have settled out as being the standards for broadcast, cable, etc, were all oriented towards CRT displays. Of course, in the sizes that make the best use of HDTV signals, these are going to disappear.
I also have wondered why they didn't just make the standard fairly open-ended in terms of supported resolutions and refresh rates. I guess they felt it would be asking too much of the kind of equipment they expected to be receiving these signals to be able to deal with it. Really it's a mindset that was locked into the concepts that worked for analog sets. As you say it would be virtually trivial for the decoding and scaling chips in modern TVs and set-top boxes to deal with a wide variety of inputs and then output something the video electronics could handle.
"Was/is there any reason not to allow broadcast in whatever format best describes the source data?"
I should add, a lot of the work that went up to setting these standards was done in the 80s and early 90s before the concepts of digital video used on computers everyday now, that we're all familiar with, were pretty exotic stuff back then. I don't think they had really come to terms with concepts like having the transmission signal properties, like frame rate, aspect ratio and resolution, essentially independent of the display's abilities. They just hadn't realized how cheap and ubiquitous the processing power needed to do these jobs would become.
As it is, digital cable and sattelite outfits use various schemes, the effective resolutions and aspect ratios on their transmissions are often wildly different than their nominal values for 1080i or 720p. And they're already moving on to MPEG4 or similar higher quality/lower bandwidth compression schemes. I've downloaded high def DivX videos that were smaller than their standard def MPEG2 versions, with less artifacting.
Black and white video was broadcast at 60.00fps to prevent beating against the AC line frequency (hooking old television sets up to some computers or video games works poorly because many computers have a frame rate that's off by about 0.1Hz). So why choose a chroma rate that causes the field/frame rate not to be 60.00/30.00Hz?
Look how the video is sandwiched between the video carrier and audio carrier.
Not a bad article, though it refers to colorburst as 3.58MHz and does not say why it is really 3,579,545MHz (nor even mention that it, in fact, is).
Well, it was advertised as "all new".I had never seen the episode before.
I've watched most of it twice now (you have to watch every second, or you'll miss an important clue) and I still need to see it a 3rd time. I tend to shut my eyes during commercials and then I'm out! Sometimes it is repeated on Sat. morn, so I hope it is today because I am still missing a couple of links to the story line. LOL.
Naturally, Monk and Natalee solve the murder. And Randy Disher and the Capt. harmonize on O Holy Night at a Christmas party. They are pretty good -- especially Randy. They actually are outstanding because they sing as if it is spontaneous and they are just doing it for the first time -- complete with mistakes and occasional flat notes. That is very hard to do!
I will say no more so I won't spoil the story.
Well you don't have to put a box on your TV. You just won't receive the broadcast anymore because the govt. will have closed down the channels you can now receive and will have sold them for other uses -- such as phones, braodband internet, etc. I don't think the Constitution has anything to do with it.
However, I think that they are sensitive to questions such as yours, and that is why they are talking about subsidizing the switch.
I am afraid that I am not being clear. My constitutional question has nothing to do with the actual merits of having the equipment or not. It is weather the government can force someone to sell their property or not. When the government mandates that a receiver (Specifically not a transmitter.) contains certain equipment, I get a chill up my spine. The FCC can recommend such equipment and people should be free to opt to trade their property for such equipment. Suppose, I know this is far out there, but just suppose the government in it's wisdom, decided as a way to curry favor with the Cherry Wood producers, mandated that all receivers must be housed in a cherry wood cabinet. I see a great similarity in both cases, because in both cases neither has an effect (assuming proper shielding) on other peoples ability to receive signals. Both cases amount to effective tariffs on property exchanges, designed to benefit the politicians buddies.
I understand your question. However, the Government owns the channels and the rights to them, as I understand it. They merely LEASE their use to the broadcasters. Once the government decides to do something else with them, the broadcasters have nowhere else to go except to this newer technology which causes a problem for the rest of us. I think the government is trying to make this as easy as possible on us with subsidies, etc.
Think about it as the same thing that happens when the government decides that the cattlemen in the west can no longer graze their animals on government land. They just have to find another place to run their herds.
This kind of thing happens all the time -- especially with National and State parks. Here in Wisconsin they are instituting new rules that govern the kind of docks people can put on their own shoreline on our many lakes. Wisconsin says the water all belongs to the state, even though the shorline may be privately owned. This is costing property owners a lot of money because nearly every existing dock does not meet the standards of the persnickety DNR!
I agree with you, it is not a pretty picture. But, the govt. seems to think it is their right.
It is also a business decision. For instance, we cannot force MicroSoft to support our older computers, even if it means that we have to spend a lot of money replacing them every few years.
I suppose I'm not the first to notice that this date is almost as far away from any election as possible. The technology is there to do it today but that might get a few of the CongressCritters in hot water. And how would you like to be running for President with 50,000,000 screaming TeeeeVeeee fans rioting in the streets.
What a world we live in.
The NTSC toob type color TVs all had a delay line in their circuitry, though the delay was much less than a scan line's worth of signal. It was put in the signal path for the monochrome video (Y) because the narrower bandwidth of the color signal path introduced its own delay. The monochrome had to be slowed down so that the color and monochrome video would arrive at the picture tube in proper sync. Having the color signals transmit twice as fast as the monochrome signal would pose a problem, but if all occupied the same width of time slot then the design would be trivial using delay lines.
What sort of technology could have implemented a delay line whose bandwidth was large compared with its period (i.e. which held a lot of "information")?
Oh, maybe a 10 foot cube filled with line...
I think Mark Was Here's complaint isn't just that the government is changing formats, but rather that they are imposing restrictions on what sorts of receivers someone can purchase.
If many people in 2008 decide that they want to buy analog receivers for use with their antique video game systems, even if they have no use for the fancy shmantzy digital stuff, the government would still require that it be included. To be sure, I suspect that--in practice--there wouldn't be much market demand for analog-only sets once analog broadcasters ceased functioning, but I see no reason why people should be forbidden from supplying whatever demand happens to exist.
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