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Thread: H.264 Codec, Wow

  1. #1

    Lightbulb H.264 Codec, Wow

    This codec is amazing!

    Apple will soon be releasing a groundbreaking/all definition codec for quicktime called H.264.

    I had the opportunity of seeing H.264 in action and talked to one of the head engineers of it, a young Check woman who's name I never took note of. The Codec will take a lot of proccessing to encode but it decodes so fast and preserves color amazingly! It's a 4:2:1 Mpeg-4 High quality codec with an inherant chroma shift of +2 that counters the compression effects. I've seen the previews of the movie Troy encoded in 1080p 24 FPS playing off the standard hard drive that comes with the machine. It played flawlessly and with no artifacts. 1 layer of 1080p on Apple's Seagate 160gb SATA hard drive is amazing. I've also seen it decoding 3 streams simultaneously, 1 720p, 1 ntsc, and one half size clip on the same setup.

    This codec will be the one to watch when it comes out. The engineer doesn't know yet what Apple's reccomended equipment requirements will be to encode content with this codec but apparently it is very slow to encode and takes advantage of dual proccesor mac G5s as well as the 64 bit architecture. I would venture to guess you will at least need a G5 but you never know with Apple.

    I've attached a white paper on non-Apple Quicktime H.264 for those of you who are masochists for technobable.

    Christian Choi
    Attached Files Attached Files

  2. #2
    Quote Originally Posted by litemover
    This codec is amazing!

    Apple will soon be releasing a groundbreaking/all definition codec for quicktime called H.264.
    Christian Choi
    Christian does it use interframe compression?


    if it uses interframe compression it wont work so well with what we do.

  3. #3

    h264 uses interframe compression

    1. Dividing each video frame into blocks of pixels so that processing of the video frame can be
    conducted at the block level.
    2. Exploiting the spatial redundancies that exist within the video frame by coding some of the original
    blocks through transform, quantization and entropy coding (or variable-length coding).
    3. Exploiting the temporal dependencies that exist between blocks in successive frames, so that only
    changes between successive frames need to be encoded. This is accomplished by using motion
    estimation and compensation. For any given block, a search is performed in the previously coded one
    or more frames to determine the motion vectors that are then used by the encoder and the decoder to
    predict the subject block.
    4. Exploiting any remaining spatial redundancies that exist within the video frame by coding the
    residual blocks, i.e., the difference between the original blocks and the corresponding predicted
    blocks, again through transform, quantization and entropy coding.
    This is the compression paradigm for h264 from the above attachment.

    Note step 3.
    This step - 'Exploiting the temporal dependencies that exist between blocks in successive frames, so that only
    changes between successive frames need to be encoded"

    this assumes that the video goes linearily and uniformly in one direction - forwards.

    Not at all good for random frame access - or seemless looping between any two points in a movie.

  4. #4
    Crap, I knew it was too good to be true.

    The preservation of color was beautiful. Do you think that it might still be a good codec to use if all videos were being played back linearly but looped?

    Christian Choi

  5. #5
    Quote Originally Posted by litemover
    Crap, I knew it was too good to be true.

    The preservation of color was beautiful. Do you think that it might still be a good codec to use if all videos were being played back linearly but looped?

    Christian Choi
    codecs that use interframe compression will work - if used in certain ways.

    i mean mpeg2 works - but just not as well. and you will not get predictable playback performance.
    And they wont play backwards very well. that kind of thing

  6. #6

    video conferencing

    this thing seems to be designed to do video conferencing

  7. #7
    Quote Originally Posted by samsc
    this thing seems to be designed to do video conferencing
    Can do, they were displaying it as a phone movie codec, a streaming codec, and a professional HD codec. They had one g5 running the Troy trailer full screen on a 23" cinema display 1080p and on another they had 720p, 480 and video phone resolution simultaneously decoding on the G5's internal hardrive, again very good quality.

    Will be interesting to see how it does when it comes out.

    Christian

  8. #8
    Quote Originally Posted by litemover
    Can do, they were displaying it as a phone movie codec, a streaming codec, and a professional HD codec. They had one g5 running the Troy trailer full screen on a 23" cinema display 1080p and on another they had 720p, 480 and video phone resolution simultaneously decoding on the G5's internal hardrive, again very good quality.

    Will be interesting to see how it does when it comes out.

    Christian
    all going in the forwards direction.....all interframe compression codecs have to assume the uniform flow of time or movie data in the forwards direction.

  9. #9
    If I could get great HD color sampling with good compression and decoding speed, I'd use it, if only for going forward.

    Christian

  10. #10
    An h264 report.

    http://www.macsimumnews.com/index.ph...dtv_recording/

    This really probably isnt going to be great in catalyst - but maybe cell processors will process this stuff really fast?

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