I just have a few questions regarding TV Formats.
1)Is a Plasma TV Digital?
2)Is a Plasma TV High Definition?
3)If i watch normal TV on a widescreen TV, will it have black bars at the side?
4)When most everyone in the world is using Digital TV (2010?) will there be any need for PAL & NTSC?
It depends what you mean by ‘digital’. Plasma displays, LCD displays, LCD and DLP projectors all have one thing in common - they take a video signal, convert it into a bitmap, and display it on the screen. So yes, it’s ‘digital’. However, it may take analog inputs or digital inputs, or both, depending on the display. Some plasma sets will have a TV tuner built in and accept an RF input, but most will probably have S-Video or Component inputs.
There’s nothing about plasma in particular that makes it high definition. Theoretically, you could could have a plasma display with only 10 pixels, and that would be pretty low-definition! In the real world, you can find all sorts of plasma and LCD displays in varying resolutions. ‘High Definition’ is a nebulous term, and there are a number of HDTV formats. The most common are 480p, 720p, and 1080i. That means 480, 720, and 1080 lines of resolution, respectively (with the horizontal resolution determined by the aspect ratio). The ‘p’ and ‘i’ stand for ‘progressive scan’ or ‘interlaced’. Progressive Scan is preferred, although 1080i would look better simply because the resolution is so high.
Most plasma sets I’ve seen can display 480p signals. A few can do 720p. But i haven’t seen one yet that can display 1080i in native format. A number of them can handle the format, but they have to scale the image down to match the display, which is usually something like 1366 X 768.
A couple of things to be aware of: The first is that any display with a digital output needs to have a ‘scaler’ built in to stretch all the various formats so they fill the display device. This can introduce artifacts if it’s not done right. On small displays it’s not as big a deal, but when you get up to a 65" plasma display or a 120" front-projection screen, those artifacts really stand out. So you have to often invest money in an external scaler, and these can range anywhere from $500 to $20,000 dollars.
The other thing to be aware of is that just because a signal is high def doesn’t mean it’s any good. Many digital cable signals are broadcast using MPEG-2 compression, which introduces its own artifacts. And as competitive pressures between Satellite and Digital Cable mount, and because resolution doesn’t seem to be much of a marketing issue so far, many cable companies are opting to offer more channels by cranking up the compression ratio. HBO in my area is particularly bad - the compression artifacts are so bad that I can see them on my 19" TV from across the room.
Oh, I forgot one more thing - all that resolution is useless unless your eyes are good enough to see it. This is something most people don’t consider. For example, for you to be able to resolve all the available resolution in a 1080i signal on a 25" TV, you’d have to be about a foot away from it. Most people don’t sit that close, so much of this resolution is wasted. So don’t bother spending money for a small HDTV set unless your face will be pressed against it.
I’m in the process of building a home theater in my house. It has an 8’ wide screen (106" diagonal), with a DLP projector in the back of the room providing the image. The projector has a native resolution of 1024 x 768, so I can display HTDV in its native format at 480p. I’m using a PC with a DVD player and ATI Radeon card for the player, which provides scaling as good as a $10,000 Faroujda standalone scaler.
If you try to display a regular VHS image through this, it looks like hell. But I am anxiously awaiting HDTV in this area, because it should look spectacular.
It should be mentioned that none of these display technologies will match the quality of an excellent direct-view TV like a Sony Wega. But Direct-View TV’s get huge, heavy, and expensive once you go past 40" or so. Plasma TV’s so far have had only average picture quality, and there have been some real stinkers out there for amazingly expensive prices.
Oh, and while Plasma TV’s are flat, they can’t exactly be ‘hung’ on the wall like a picture, because they are extremely heavy, and will require special mounts and maybe even wall reinforcement. Plus, you’ll want to run your power and signal cables inside the wall, so installation isn’t easy, and once the thing is installed on the wall it’s a lot harder to move than a regular TV.
I have high hopes for plasma, but IMO they aren’t quite ready for prime-time yet. Maybe in a year or two.
A few months ago I saw a true-HD (1080 x 1920 interlaced) plasma screen at Bay Bloor Radio in Toronto. It was marked down to only 35 000 dollars Canadian. Somebody must not have objected to spending most of an average year’s salary on a TV screen, because I came back later and it was gone: only the 600-dollar bracket remained…
35G’s Canadian is nothing. If you delve into the world of Home Theater, that’s a pittance.
There are plenty of theaters out there that cost more than $100,000 to build and equip. The average is probably somewhere around 30-50 thousand.
A CHEAP home theater projector is about $3,000, and the expensive ones can be $35,000 and up. Add in a $20,000 scaler, $15,000 worth of speakers, $20,000 worth of amps and processors, $40,000 for an Owens-Corning acoustic Room System, $3000 for a screen, $2000 for an electric masking system…
Then you can get into the real insanity - there are POWER CORDS out there worth $2000. I’m talking about a replacement for your black power cord. I saw one theater that used two Sony G90 projectors stacked one on top of the other to improve brightness (G90 ~$25,000, much more a couple of years ago). Then there’s the custom theater seats which most people buy, which can run $1500 a pop or more. Put 12 of those in the theater.
And what does all this get you? An incremental improvement of maybe 10-20% over my theater, which will come in at about $10k in total. As in anything else, it’s the last few percentage points of performance that cost a fortune.
They will eventually fade away and become useless when broadcasters no longer transmit these formats. But 2010 might be ambitious, at least in the US. Many broadcasters here are dragging their feet and the FCC deadlines for when cities were to switch over to digital are constantly being missed and pushed back.
Well, considering the primitive state of television broadcasting in many third-world countries, I’d say it’ll be a lot later than 2010 before analog completely fades away…
BTW, Sam Stone, excellent HD treatise.