Do all Progressive Players have good interlaced Performance also?

Discussion in 'Archived Threads 2001-2004' started by Jason Bell, Oct 18, 2002.

  1. Jason Bell

    Jason Bell Stunt Coordinator

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    My 2 year old Philips DVD player has been locking up more and more frequently so I'm looking for a replacement. I have around $200 to spend. I also just purchased an Analog Flat Screen so the interlaced performance is really important to me. Do any of the entry level progressive players sacrifice interlaced performance because they feel most consumers will be using the progressive mode? I'd also like to continue to use my S-Video cable to connect it to my T.V. do any of the new players sacrifice the quality on this connection assuming people who care about performance would be using the Component connections anyways? Thanks
     
  2. Steve Schaffer

    Steve Schaffer Producer

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    Jason,
    All progressive scan players except the JVCs derive the progressive scan picture from the interlaced one, so the interlaced picture will be the same quality as on an interlaced-only player.

    JVCs derive the interlaced from the progressive, so unlike other players the 3/2 pulldown affects the interlaced as well as the progressive scan signal. This means any pulldown errors will affect the interlaced picture which is not the case with other makes.

    The Panasonic players will output progressive scan via component and interlaced via S-video simultaneously, as well as interlaced from both connections simultaneously.

    There is no reason why a progressive scan player in interlaced mode would put out an inferior S-video signal compared to a non-progressive player. They don't skimp on anything as far as the S-video connection goes.

    That being said, you will still get a noticeably better picture using the component connection if your set has one even with interlaced output. The only reason I can think of to use the S-video is if you need to go through a receiver that doesn't have component video switching. Even in this case it's better to run the audio to the receiver and the video straight to the tv via component connections.
     
  3. Jason Bell

    Jason Bell Stunt Coordinator

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    Thanks Steve,
    That answered all my questions. I just picked up a Toshiba 4800 earlier today. I also bought a set of component cables to connect it. The picture is noticeably better than my other player. I didnt try it with the S-Video connection so not sure if the improvement is the player or the connections. Probably a little of both. Betters Better[​IMG]. Thanks again. Also no lockups so far.
     
  4. Allan Jayne

    Allan Jayne Cinematographer

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    Theoretically, compared with the component video connection, the DVD player S-video connection gives slightly less crisp color transitions. A few folks put up with that just so everything can go through the A/V receiver in the manner that gives the most convenient switching.
    An aside, are the JVC progressive players that obtain their S-video output by re-interlacing the progressive scan video, free of the chroma bug (chroma upsampling error)?
    It appears to me that the chroma bug also shows up in interlaced DVD players and the only way to fix it is to have on hand (using buffers) simultaneously both the current odd or even field and the even or odd field that came before, which is the same strategy needed to make progressive scan. One way of fixing the chroma bug is to apply some of the color that came with the even field onto some of the scan lines of the odd field, and vice versa.
    Video hints:
    http://members.aol.com/ajaynejr/vidbug2.htm
     
  5. Steve Schaffer

    Steve Schaffer Producer

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    Allan,
    Both Panasonic and JVC are free of the chroma bug.
     
  6. Don Munsil

    Don Munsil Stunt Coordinator

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    Allan,

    All DVD players, even non-progressive ones, have to read in and construct the complete MPEG picture. Since the MPEG picture is almost always a complete frame (2 fields), the player doesn't have to do anything special to get the information necessary to fix the chroma bug.

    It's part of the MPEG spec -- the macroblocks refer to the frame, not to the individual fields. So even though the player is going to output single fields, it *must* have enough buffer memory to handle a whole frame.

    So within the MPEG decoder, there's no need to apply any hacks like smoothing the chroma channel. The decoder just needs to upsample the chroma channel properly in the first place. The chroma channel filtering that some "chroma bug solutions" use is only necessary because they can't get inside the MPEG decoder to fix it properly.

    When I think about the tiny amount of effort and programming required to fix the chroma bug, it just amazes me that it still exists. And this isn't just my supposition - I've spoken to engineers who have fixed it, and (assuming the decoder was architected properly to begin with), it's generally a fairly trivial change. It's just that there are still manufacturers who don't see it as a problem. Shrug.

    Oh, and the bug is definitely present in interlaced players as well. It's just harder to see on an interlaced display. But not impossible.

    Steve,

    It's not just the JVC progressive players that derive the interlaced output from the progressive. It's all the players that use the Mediamatics/National Semiconductor chipset. That would include the Malata, one of the Apex players, and a handful of others. FWIW, I was told specifically by the head engineer at Mediamatics that it is not *necessary* to derive the interlaced from the progressive output, but I have yet to see a player that does it properly.

    Don
     

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