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Forums AJA Video Systems MJPEG-A

  • MJPEG-A

  • Jeremy Garchow

    September 20, 2005 at 6:18 pm

    What will we gain or lose by using this codec? How does it match up with the other apple codecs? SHould I start using it? Will it be yet another option for compressed HD in the not so distant future?

    Sorry for all the questions, just had to ask.

    Jeremy

    ———–
    G5 Dual 2Ghz <> 4GB RAM <> FCP 5.02 <> Kona 2

    ATTO 42XS <> Huge Systems 1.25 TB 4105 Fibre

  • David Battistella

    September 20, 2005 at 7:05 pm

    Well. Mjpeg is a nice variable frame size codec. Letting you go from 1k-13.3k in SD.

    It is also a 4:4:4 codec when it is at 100% that is tprobably the biggeset thing you gain.

    Problem will be this: it is a compressed codec so that means there is likelyhood of a lot of RT. Uncompressed actually gives you more RT because as you add to an uncompressed stream you are not asking the computer (or in some cases the card) to do all of the compressing on the fly. Some codecs (the DV codecs for example) are very good at this and their algorithms allow for multiple streams and they have been “optimized for video”. Many people would like to see this type of optimization with the M-Jpeg codecs because they are so flexible. This might also pave the way for some mixxed resolutions in the Timline. IE. a 1k, 5k, nd 13K Jpeg compression rates all playing back in one timeline.

    That is some of it. I think it also carries an alpha channel. Graeme Nattress has many opinions on this, maybe he will find this thread.

    David

  • Graeme Nattress

    September 20, 2005 at 7:13 pm

    No Alpha as far as I remember. Personally I like PhotoJPEG75% (Y’CbCr 4:2:2) and PhotoJPEG100% (RGB 4:4:4) as very lightly compressed codecs for both SD and HD. There’s no real time on them at all in FCP, but someone posted a hack on the decklink forum here at the cow to allow that.

    Graeme

    http://www.nattress.com – Film Effects and Standards Conversion for FCP

  • Marco Solorio

    September 23, 2005 at 3:39 am

    One example is that MJPEG-A is a better codec than DV50; you can control the amount of compression there is with MJPEG-A while remaining in 4:2:2. This gives the user an incredible amount of possibilities when they want something better than DV50. I think this is a great move by AJA.

    Marco Solorio  |  OneRiver Media

  • Marco Solorio

    September 23, 2005 at 3:40 am

    [David Battistella] “It is also a 4:4:4 codec when it is at 100% that is tprobably the biggeset thing you gain. “

    It is PhotoJPEG that jumps to 4:4:4 in 100% quality mode, but MJPEG-A and MJPEG-B do not inhibit this feature.

    [David Battistella] “I think it also carries an alpha channel.”

    No alpha channel on MJPEG-A, MJPEG-B or Photo-JPEG. You’d get a bad matte since the color channels are compressed.

    Marco Solorio  |  OneRiver Media

  • Jeremy Garchow

    September 24, 2005 at 3:22 am

    Thanks Marco.

    I assume you mean control the compression by adjusting the quality slider (oercentage), correct?

    ———–
    G5 Dual 2Ghz <> 4GB RAM <> FCP 5.02 <> Kona 2

    ATTO 42XS <> Huge Systems 1.25 TB 4105 Fibre

  • Marco Solorio

    September 24, 2005 at 8:02 am

    [JeremyG] “I assume you mean control the compression by adjusting the quality slider (oercentage), correct?”

    Yes, this is correct!

    Marco Solorio  |  OneRiver Media

  • David Battistella

    September 24, 2005 at 2:02 pm

    Humbled by the codec king again.
    🙂

    d

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