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Pal Progressive Dvd's Disks?? Do They Exist??

Discussion in 'Projectors, Screens & Video Processors' started by willowbob, Oct 21, 2002.

  1. willowbob

    willowbob
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    Maybe I'm wrongly informed , but don't dvd disks have to be encoded as progressive and then you make full use of them with a progressive dvd player and tv?

    What is all this talk of people saying they try their disks with their progressive tv and/or dvd player and they get a better picture?

    Is there a PSEUDO progressive image displayed for dvd disks that aren't encoded as progressive?
     
  2. JohnAd

    JohnAd
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    willowbob

    The whole area of MPEG encoding is very complex. In summary DVD are encoded as interlaced but using a simple method of turning each flm frame into interlaced fields. Well encoded films will also set flags in the MPEG stream to say that the material was originally film. A flag reading player will only work if these flags are correct and will contruct a progressive film frame using these flags. Even if the flags are not set properly there are other chips/boxes that will spot the film patterns and reconstruct the progressive image. Most progressive players use a non-flag reading chip set so that the DVDs don't have to be encoded correctly.

    Hope that helps

    John
     
  3. Jenz

    Jenz
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  4. They

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    There are many ways to encode video and film material via the MPEG2 standard and not all DVDs are encoded in the most consistent, reliable or sensible way. But so long as they can be decoded correctly for output on an interlaced display then they are considered marketable!

    The most efficient way to encode progressive sources such as film to DVD is by encoding as progressive frames and this is what you will find on most DVDs, however, because DVD and DTV was designed for interlaced display then the MPEG encoding will include data flags to enable the MPEG decoder to convert whatever is encoded into a correctly interlaced output. The progressive frames for film will be described on the DVD as an interlaced sequence of progressive frames with other data flags for field display order and pulldown sequencing.

    In essence it doesn't matter, for the sake of progressive output, if the film is encoded as interlaced or progressive because most progressive DVD players use a de-interlacer that receives the interlaced output from the MPEG decoder and converts it to progressive (no matter what the original source).

    The de-interlacer in the DVD player (or any de-interlacer for that matter) needs to be of high quality of course. The Sil504 and Faroudja 2000 series are popular and of a very high quality.

    DVD players that have de-interlacers that rely mostly or only on the MPEG2 data flags are to be avoided.
     

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