MPEG decoders that can "fix" poorly flagged DVD's

Discussion in 'Archived Threads 2001-2004' started by RyanDinan, Jan 23, 2002.

  1. RyanDinan

    RyanDinan Stunt Coordinator

    Oct 25, 2000
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    Hello everyone,

    I was on a discussion on another forum, and this idea came up.

    The discussion was started because I recently bought a new DVD (American Pie 2, widescreen, rated version), and it has some bad flags during the last two (or three?)chapters.

    This flag (progressive_frame true/false) was set accidentally to false, which makes the MPEG decoder handle the full frame of film as two different interlaced fields. This causes the video to pulsate or strobe - very nasty.

    On a DVD release as "big" as this one, you'd think that the mastering studio would pay attention to these kinds of details - especially with the fact that there are more HDTV's in consumers homes these days.

    Well anyway, we thought that if the MPEG decoder had the ability to "override" certain flags such as these (and had a memory for each disc), the problem would be fixed. In this case, the MPEG decoder would be "smart" enough to know that this flag should be set to TRUE for this kind of material.

    Of course, there would have to be some kind of fuzzy logic to discern what needed correcting..

    Just an idea..

    What do you think? This would definately be a better solution than implementing all kinds of different de-interlacing algorithms on the fly, switching back and fourth..


    -Ryan Dinan
  2. Todd Hochard

    Todd Hochard Cinematographer

    Jan 24, 1999
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    AFAIK, this already exists. This is essentially how the DVDO decoders (or should I say deinterlacers?) work, by recognizing cadence instead of flags.

    My Pioneer Elite 510 is the same way. I watched this flick (from an interlaced player, with deinterlacing by the set's line doubler), and I didn't notice any of the video anamolies that you speak of.

    Perhaps a "best-of-both-worlds" type- one that relies on flags, until the cadence circuit has a discrepancy, then it takes over.

  3. John Kotches

    John Kotches Cinematographer

    Mar 14, 2000
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    No MPEG decoder can fix this problem. It isn't an MPEG encoding flaw.

    The deinterlacer is what would fix this problem.

    Cadence reading deinterlacers could solve the problem.


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