Newbie question: HDTV & EDTV: What the diff?

Allan Jayne

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EDTV is SDTV (standard def.) with some enhancements to make the picture look smoother and hopefully preserve practically all of the picture detail the (SDTV) source had originally.

In terms of technology, EDTV is at least 480p. (Progressive as opposed to interlaced). Since all non-CRT TV's have non-interlaced display, one might categorize all of those non-hi-def models (excluding things like pocket TV's, cell phone TV's, and the 320x240 pixel models) as EDTV.

Video hints:
http://members.aol.com/ajaynejr/video.htm
 

JeremyErwin

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Um, no. That's not correct.

There are 18 varieties of hdtv, ranging from 480i60 to 1080p30.
The 480i variants are called sdtv.
The 480p variants are called edtv
The 720p, 1080i, and 1080p variants are called hdtv.

sdtv is analogous to the old 525 line ntsc system. If fed with sufficient bandwidth, (few are), it should look like a DVD, and in many respects, including color definition, can be superior to the old ntsc standard.

edtv is a progressive format. It's already deinterlaced, so it should look superior to a DVD.

and then there's hdtv--720p, 1080i, and 1080p. ABC and Fox use 720p, most every other broadcaster broadcasts in 1080i. 1080p is very rare, and it may be that there are no stations using it.

Now, you can deinterlace, upscale, and downscale to your heart's content-- but most of those processes add noise, and can't add detail.
 

ChrisWiggles

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EDTV is basically 480p or higher but not 720p/1080i or higher which is HDTV.

This has to do basically with the display's resolution capabilities, not the source.


This is also meaningless, terrestrial SDTV broadcast is NTSC. Further the statement that it should look like DVD or is superior (especially w/regards to color) is incorrect. NTSC does not have the capabilities of DVD which is a Y'CbCr format. NTSC is a single composite summed Y'UV (Y'/C) modulated signal. S-video is similar, but is not summed and remains separate Y'/C. Component keeps each chroma component separate, but generally at reduced bandwidth.
 

ChrisWiggles

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I'm not sure how what I said has any relation to Kris's ratings of DVD players.

DVD is a 480i format, film-source DVDs the content itself 480p24 written as 480i60. There's no 480p60 involved at least with DVD. It is all 480i60 on the disc, film content itself is 480p24 as far as the nature of the content is concerned.

I'm having difficulty discerning what your point is. I'm not particularly that interested in hasing out the details of what an "EDTV" is, which really just arose as a confusing marketing term by manufacturers to attempt to distinguish one product or another as more than SD but not HD.
 

JeremyErwin

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A number of cinematographers have experimented with faster film rates than 24--it's better for certain kinds of action shots, but have been stymied by the costs involved-- film stock, projection equipment, etc. edtv and hdtv support 60 frames a second, progressive. sdtv doesn't. dvd doesn't.

Theoretically, dvds have a flag that tells the deinterlacer which algorithm to use. Some dvds, however are misflagged. The better dvd players ignore the flag, and analyze the video to determine which pulldown algorithm should be used. If the format was 480p in the first place, with deinterlacing done at the mastering stage, many of these problems would disappear.
 

ChrisWiggles

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I never said the format was 480p. I said film-based content was p24 content. The DVD format is nominally 480i60. The difference between the nature of the content itself and the form it takes may seem subtle, but is very important. Film based content on DVD is written nominally as 480i60, but is actually fully reconstructable as 480p24. It is most accurate to describe the nature of the content itself (but not it's form) at least as far as film-based content goes, as 480p24.

Obviously video-based content is 60i usually, though there are a variety of other cadences possible which one might run into in less common cases.
 

JeremyErwin

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some of the infocus projectors use a 854x480p matrix, and it is perfectly possible to display progressive video on a crt-- consider computer monitors. But two years ago, slate said edtv was a waste of money. Now, with atsc broadcast, hddvd, bluray, and host of other media to consider, it's even more so.

Better than sdtv, perhaps, but hdtv is the future.
 

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