Film-Tech Forum ARCHIVE: About progressive scan

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Posted by Frank Angel (Member # 248) on 03-01-2004, 11:00 AM:

I am a little confused about DVD players that claim have progressive scan. I understand that while the DVD player can have progressive scan capabilities, I don't see how that can improve performance on any display unit that is designed to produce a picture by interlacing the scanning lines. A DVD player, be it an interlace or progressive scan unit, cannot change the way the picture is displayed by the display unit, right? Or am I missing something here?

I recall Toshiba made a TV set that used progressive scan processing (by storing the image as it was received and then displaying it all at once as a complete progressive scanned picture). But if the display system is interlace, what difference will the DVD player make? It's like a sound system that sends a stereo signal to a mono playback system.

Someone enlighten me.

Posted by Paul Linfesty (Member # 214) on 03-01-2004, 12:46 PM:

first, a progressive scan DVD player is also an interlaced DVD player, which is the default.

You're absolutely correct, a DVD player with progressive scan does nothing for interlaced TV's, since you have to send out an interlaced signal from the DVD to playback on a standard TV.

The progressive scan mode is there for "future-proofing" so that when (if)you do purchase that progreSsive scan TV, you already have the progressive scan DVD player ready.

And while it is true that progressive scan TV's can take an interlaced signal from a DVD player and convert it to progressive, it is using a logic chip to do so, and in some cases might get the 3:2 cadence wrong, while a DVD player will make the interlaced info progressive on the basis of encoded flags on the DVD itself (although in a few occasions, these flags have been improperly encoded).

Posted by Ian Price (Member # 14) on 03-01-2004, 04:06 PM:

That said, a progressive scan DVD played on a video monitor that can display a progressive scan singnal looks very good. All HDTV ready displays will accept a progressive scan signal so DVDs will look better on these displays than the same DVD on an interlaced display.

Posted by Steve Guttag (Member # 268) on 03-01-2004, 07:33 PM:

Progressive scan really only has meaning for CRT type displays. As for HD...the "standards" are 480i, 480p, 720p and 1080i though there is 1080p. Digital display devices don't work on the scan line thing so at that point they will essentially turn everything into the progressive scan look. Technology also is making the 3:2 pull down conversion better and better are more of a matter of fact. While I'm still a big proponent of scalers...some projectors now really have that area reasonably well covered except for having multiple inputs.

Steve