Is progressive DVD player really worth it? (1 Viewer)

[Francois Plouffe]

Hi, I am not sure if it the right place to ask this, but anyway.

Is the content on DVD encoded progressive or interlace?. Which of the following statement is true?

Statement 1: if the content on DVD is progressive, that mean regular DVD player convert the image to interlace to play on regular tv.

Statement 2: if the content on DVD is interlace, that mean the opposite; progressive DVD player have an internal line doubler to output a progressive image (to a progressive display).

My dilemna is that I have a regular DVD player and I have a HDTV (with an internal line double of course). If statement 1 is true, buying a progressive DVD player will be worth it.

If statement 2 is true, then I will keep my trusty 5 years old Panasonic A100 until it dies.

 

[Jeff Adams]

I'm not sure about all the technical sides of this. But I do know that a progressive scan dvd player is the way to go. I used to have a normal dvd player hooked up to my hdtv , when I switched to a progressive scan player, it was like night and day difference. If you have an hdtv then I would say a progressive scan player is a must. There are so many good progressive scan dvd players out there that are very affordable. Also, an anamorphic or enhanced for 16x9 tv dvd will take full advantage of a progressive scan dvd player. Most dvd's today are presented like that.

 

[Francois Plouffe]

Anyone else? Thanks.

 

[Clinton McClure]

I concur with Jeff.

 

[Mike I]

With an HD ready set, go progressive, you will not be sorry...

 

[Francois Plouffe]

That's what I thought.

But, can anyone answer technical question? Is the DVD progressive by nature or is there a line doubler inside progressive DVD player?

Thanks.

 

[MichaelW]

It's important to understand at the outset that DVDs are designed for interlaced displays. There's a persistent myth that DVDs are inherently progressive, and all a DVD player needs to do to display a progressive signal is to grab the progressive frames off the disc and show them. This is not exactly true. First of all, a significant amount of DVD content was never progressive to begin with. Anything shot with a video camera, which includes many concerts, most supplementary documentaries, and many TV shows, is inherently interlaced. Only content that was originally shot on film, or with a progressive TV camera, or created in a computer, is progressive from the get-go. But even for such content, there is no requirement that it be stored on the DVD progressively.

Lots more and probably all the answers to your questions can be found at:
Link Removed

 

[Ergin Guney]

But, can anyone answer technical question? Is the DVD progressive by nature or is there a line doubler inside progressive DVD player?

The link given by MichaelW does contain the answers to all of your questions. But I'd like to repeat the "nutshell version" of the answer here anyway. (It might help if you or anyone else reading this didn't have the time to go through all of that article.)
DVDs contain "interlaced" video. But there is a catch, and a big one at that: The disk also contains information as to how to return this interlaced video into progressive form perfectly (i.e., so that only the correct interlaced fields that do belong together end up in the same progressive frame). Using this information, the DVD player can output a progressive signal that is literally identical to how it would have been if the disk contained a progressive recording to begin with.
Given that, any outboard or TV line doubler (used with an interlaced-only DVD player) would be at a disadvantage with respect to using a progressive-scan player for at least two reasons:

• The outboard line doubler has to figure out on its own which fields should go together to make each original frame, and it has to do this by looking at nothing more than the video image itself. The DVD player, on the other hand, has access to those explicit hints recorded on the disk as to which fields belong together. So the player has "inside information", so to speak, that an outboard decoder can never have. Although many mid- to high-end TVs do come with very good line doublers that do a perfect job most of the time anyway, many other TVs don't. Besides, even the ones with the "perfect" line doublers can sometimes take a few frames at the beginning of a new scene/chapter/disk (at least when set to "auto" mode to figure out video- versus film-sourced images on its own) to detect the correct 3:2 pulldown ordering of the fields to follow in order to convert to progressive scan correctly, whereas this should never happen with a progressive DVD player's using the hints recorded on the disk.
• The outboard line doubler has to use the analog interlaced video that is being sent to it. Since virtually all line doublers work digitally, this means that the image has to be converted back to digital for processing, and again back to analog for being displayed on the CRT. The progressive DVD player, on the other hand, can do the conversion to progressive scan even before the first time the signal is converted to analog, saving you a quality-degrading analog-digital-analog conversion cycle.

One caveat, having said all this: Early cheap progressive-scan DVD players were no better than outboard line doublers, and in some cases were even worse. Because they were simply regular interlaced DVD player with built-in line doublers that worked on the analog output signal the same way the built-in line doubler of a display would. And usually it was a worse line doubler at that, due to the price point at which the player needed to sell. I believe many of the cheapest progressive-scan players on the market may still be doing this or have similar shortcomings. But recently at least Sony and Panasonic released inexpensive progressive-scan players that does this the right way and in an excellent manner.

 

[Francois Plouffe]

Ergin, MichealW,

Thanks to you both, I didn't expect that much information. I think I will begin investigation on a new DVD player.

Thanks again.

 

[Don Munsil]

Ergin,
You are right on most points about the inherent superiority of progressive DVD players over deinterlacers in TVs. A few corrections:
- Many, but not all, DVDs contain the "hints" you are talking about to reconstruct the frames (actually, they contain the frames themselves, plus flags that tell the player the intended timing for each frame). As the article points out, there is no requirement at all that the video be stored this way, and far too often it's not. Sadly, this hasn't really changed much. We're still seeing discs with odd flags, wrong flags, cadence breaks, bad edits, etc.
- The very best progressive DVD players ignore the flags on the disc and use cadence analysis to reconstruct the original film frames. Flag analysis is used because it's cheap, not because it's more accurate. There are a handful of newer players that use a hybrid approach of trusting the flags in some cases, and doing frame analysis in other cases, but it's primarily a cost savings.
- There has never been a progressive DVD player that deinterlaced the analog output of the player. All progressive DVD players, including the cheapest, crappiest ever made, do the deinterlacing to the digital signal, before the conversion to analog. The idea that they ever did it any other way is a persistent rumor that I really wish would go away.
And Francois, to answer your question, all progressive DVD players contain a deinterlacer (often called a "line doubler," which is a term Faroudja coined). The advantage of a progressive DVD player is generally twofold:
- The deinterlacers in DVD players tend to be better than the ones in TVs (though this is rapidly changing as TVs get better deinterlacing chips).
- The DVD player does the deinterlacing to the original digital signal and avoids the extra analog/digital/analog conversion steps.
Read the article for more (full disclosure - I wrote it). Feel free to ask questions if any of it isn't clear.
Best,
Don

 

[Ergin Guney]

Don,

Thank you for the corrections. And I'm relieved that I was wrong about early cheap progressive players using a regular built-in line doubler.

Those are valuable insights.