MPEG2 (DVD) codecs: do they vary?

Discussion in 'Amateur Video Production' started by les, Oct 8, 2003.

  1. les

    les Guest

    I have a curious problem, and wonder if the compression codec for MPEG2 in
    Studio 8 is the root issue, or something else.
    I've tried burning the DVD using the 60 min (high Q) setting on two separate
    ocassions with
    the same basic complaint: any fade-to-black or dark scene has a horrific
    digital artifact
    resembling faint crosshatching or blocking. Mind you I'm exaggerating the
    faint images,
    but still it's annoying and makes it look like a cheesy production.(normal
    lite scenes look fine)

    I let Studio 8 compress on a 2Gighz AMD in Win2K, using a DV cam. The source
    is pristine, the edited DV stream is as clean as the source. The problem
    only creeps in when
    the compression happens.
    My tabletop DVD plays commercial DVD's without a hint of black blotches or
    artifacts, but both my
    authored DVD's are consistently affected in this fashion.

    So, are the codecs in Pinnacle cheap, or ineffective, or buggy?
    Is there another codec I should consider ? Are software codecs a poor
    solution to hardware

    les, Oct 8, 2003
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  2. les

    Dan Maas Guest

    There is a HUGE range in MPEG-2 encoder quality, speed, and price.

    Most mid-range software encoders are OK, if you are careful with the
    This could be due to the encoder's treatment of black levels.
    Unfortunately there is no standard for the RGB->Y'CbCr color space
    conversion, and this is one of the biggest problems with software
    encoders. Some encoders treat RGB 0 as Y' 0 and some treat RGB 0 as Y'
    16. You encoder may also be (incorrectly) applying some kind of gamma
    function. I suggest that you simply use the controls in your editing
    software to darken the video a bit and see if the artifacts go away.
    Fades to and from black are some of the toughest challenges for
    MPEG-2, but at a high bitrate it should not cripple image quality.

    I also suggest that you look at TMPGEnc, which is a surprisingly good
    MPEG-2 encoder for the price. And it gives you explicit control over
    the RGB->Y'CbCr mapping.

    Dan Maas, Oct 8, 2003
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