DVD's and scaling. When, why and how with which DVD players???

Discussion in 'Archived Threads 2001-2004' started by Chris PC, Mar 28, 2002.

  1. Chris PC

    Chris PC Producer

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    How does one scale the following to fill a 16:9 HDTV:

    1) Interlaced DVD output

    2) Non-anamorphic interlaced output

    3) Non-anamorphic progressive output

    Which DVD players, interlaced or progressive will scale non-anamorphic for you and which displays will do.

    I'm looking for which players and HDTV's do a good job of scaling and perhaps which players do not. For instance, I keep hearing that the RP-56 has no aspects ratio control. What does that mean to me if I use the player with an HDTV?
     
  2. Marc Rochkind

    Marc Rochkind Second Unit

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    I'm not sure I understand all of your question(s), but here's a try:

    All 16:9 TVs and all 4:3 TVs with a 16:9 mode ("vertical compression") will handle the output from a DVD player playing an anamorphic DVD if the DVD player is set to 16:9 mode, which it should be with these TVs. It's not that the TVs care about anamorphic per se, but rather than they just fill their screen with the unaltered image coming from the DVD player, which is what you want. With some TVs you have to switch them to full-screen mode (or whatever the TV calls it), and with others they switch automatically. But all can do it.

    If the DVD is non-anamorphic, the DVD player (if set to 16:9 mode) does nothing differently. The unaltered picture is still sent to the TV. However, the TV needs to do something differently, and there are two things the TV can do with the image from the player:

    1. Show it in 4:3 mode, with bars at the sides. This is correct if the image on the DVD is 4:3.

    2. Zoom the image so it overfills the screen, but fits the width of the screen. This is good for letterboxed DVDs where the widescreen image is within the 4:3 image.

    Whether the signal is progressive or not has no effect on what the TV needs to be doing with the image from the player. However, I think there are some 4:3 TVs that won't handle progressive input when in 16:9 (vertical compression) mode. Not real sure about this limitation, however.
     
  3. Marc Rochkind

    Marc Rochkind Second Unit

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    Oh yeah... one more thing.

    For non-anamorphic letterboxed DVDs, there are players than will zoom the picture, so the TV doesn't have to. I'm not sure which players do it. I learned just the other day here that there are some advantages to the player doing the zooming, rather than the TV. However, I don't know how significant these advantages are, and for some player/TV combinations, it might turn out that it's better to do it in the TV anyway.

    Not much of a definitive answer... sorry!
     
  4. Allan Jayne

    Allan Jayne Cinematographer

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    When the player does the zooming of non-anamorphic letterbox programs, it is better only if the player is progressive scan and only if the player completes the de-interlacing before commencing the zooming.
    For interlaced players, the zoom has to be done one field at a time and artifacts are much more conspicuous. Sometimes the artifacts are hidden using a process called vertical filtering which is no more than blending adjacent scan lines which softens the picture.
    The idea of having the player do the zoom is because some TV sets won't let you zoom the progressive input. Also when the TV does optical zoom, the middle 360 scan lines are simply spread out. When the player does the zoom, the picture is spread out onto 480 scan lines. This means the gaps between scan lines are narrower because the TV no longer has to space anything out.
    More:
    http://members.aol.com/ajaynejr/video.htm
     
  5. Chris PC

    Chris PC Producer

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    Very cool. Man this stuff is complicated. So with an interlaced DVD player, you're left with the TV zooming the non-anamorphic dvd no matter what. With the progressive dvd players doing it, it works better, provided its done after the de-interlacing.
    One thing I don't understand is that you say zooming actually spreads the scan lines out? That sounds kinda weird. Thats actually changing the resolution of the TV's display. What about reverse scaling? TV's don't do that?
    Which TV's zoom best (essential for widescreen laserdisc cause you have no choice (ie no progressive signal unless you scale it externally?)) and which progressive dvd player zoom best? I can give a couple examples and maybe someone can supplement.
    I understand the Pioneer SD533HD does good line doubling. Can I assume its zooming is good also?
    Panasonic RP-91 has good aspect ratio control. Is this what is needed for zooming non-anamorphic dvd's??
    thanx
    [​IMG]
     
  6. Marc Rochkind

    Marc Rochkind Second Unit

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    Allan:

    You mention TVs that do optical zoom. Are there also TVs that do it non-optically, by somehow processing the scan lines? Might this be tied into sophisticated line doublers?
     
  7. Allan Jayne

    Allan Jayne Cinematographer

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    Conceptually the TV can do electronic zoom a.k.a. upscaling. I don't know which TV sets do which kind of zoom.

    Electronic zoom in a TV has the same problems of more conspicuous artifacts it it is done directly on incoming interlaced video in a totally nonprogressive setting or prior to de-interlacing.

    Spreading out the scan lines in optical zoom consists of increasing the overscan in the vertical direction only.
     

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