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Forums Compression Techniques 8 Channel H.264 Quicktime Files

  • 8 Channel H.264 Quicktime Files

  • Dan Charrington

    January 12, 2011 at 4:37 pm

    To keep it short, I have a workflow that has been put together with one glaring issue that I haven’t been able to solve.

    We have HD material with 8 channels of audio (5.1 mix + Stereo pair on Ch.7&8) that we record on to XDCam discs and pull MXF files off of with Vegas.

    I’ve been asked to also create HD Quicktime files with H.264 codecs that RETAIN all eight channels of audio in their entirety. We’ve been using a Final Cut Studio station to handle the output of all things Quicktime, but when it comes to these, there seems to be issues.

    Exporting the MXF files into Quicktime files with the Apple XDCAM codec is easy enough with “XDCam Transfer”, which we have. Exporting the Quicktime (XDCAM codec) files into Quicktime (H.264 codec) files also seems easy enough with Compressor, but for some reason the audio information always gets downmixed to channels 1 and 2.

    I’ve tried using the Linear PCM setting with both the STMPE DTV configuration as well as all the 7.1 variations, as well as AAC audio with all its 8 channel configurations. It’s the same thing. (Although oddly the audio gets mixed down to channels 2 and 3).

    Apparently letting the audio “pass-through” isn’t an option either since XDCam Transfer spits out the audio channels at 24-bit, but I’ve been asked specifically for 16-bit. Lousy restrictions.

    Is there something I’m missing with Compressor? (Or possibly XDCAM Transfer?) I tried downloading a movie trailer from Apple’s website, which had AAC 5.1 audio and ran it through Compressor with the Linear PCM (STMPE DTV config) setting and there wasn’t a problem. It’s very strange.

    Dan Charrington
    Supervisor, Non-Linear Technologies

    635 Queen St E. Toronto, ON

    MacPro 8-core Xeon 2.8GHz, 10gb Ram, AJA Kona 3 SD/HD

  • Steve Smith

    January 12, 2011 at 8:41 pm

    I have the same issues with Compressor.

    We have XDCAM HD files with 8 Channels, and DVCProHD files with 16 channels of audio- both formats need H264 low res files with the same audio channel configuration.

    I don’t see anyway to do this with Apple Compressor.

    Rhozet Carbon Coder will allow you to create an H264 with multiple audio channels, but even Carbon Coder limits H264 files to 6 pairs of audio (12 channels). I’ve contacted Rhozet about this they say
    it will be addressed in a future release.

    I’ve also tried Episode Pro – but it seems like the audio always gets mixed down in there too.

    If anyone out there has a solution, I would really appreciate the help.


  • Jeff Greenberg

    January 13, 2011 at 8:37 pm

    MainConcepts makes a mac package called Reference for OSX.

    It looks like it might do what you want – an XDCam QuickTime with 8 audio tracks.


    Jeff G

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