Latest post Wed, Dec 15 2010 10:46 AM by betonpfeiler. 4 replies.
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  • Sat, Dec 4 2010 6:17 PM

    [solved] via Workaround: Force reencode.../ Gammashift

    Hello everyone!

     

    I need to run some Codectests with the DNxHD and XDCAM HD422 codecs.

    I'm quite new to Avid so I could use some help, so here are my questions:

    1. Is there no other way to export DNxHD, other then via Quicktime?!?

    2. Is there a force recompress option hidden somewhere

     

    I want to make 7 Generations of one Codec, so is there a possibility to force Avid (MC4) to recompress all frames?

    my XDCAM workaround was:

    Import natively as XDCAM, export to BMP, import as 1:1 MXF and Export to Device (External drive with fake XDCAM  HD422 Folderstructure) as XDCAM 2.Generation. 

    I did this for quite a while until the 7th generation...

    I don't want to do this for all DNxHD Versions and all 4 Testsequences too...

    Any help welcome!

    Thanks

    J

     

  • Mon, Dec 6 2010 1:00 PM In reply to

    Re: Force reencode...

    No one has any idea?

  • Mon, Dec 6 2010 3:56 PM In reply to

    • curiosity
    • Top 150 Contributor
    • Joined on Thu, Oct 13 2005
    • Boulder, CO
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    Re: Force reencode...

    I'll take a shot at this.

    1) There are a whole bunch of formats you can export to (Image Sequence, MXF, AAF, ALE, HDV, AIFF, WAV,...etc). What format would you like to go to that is not coverred? (Reading between the lines of your post I think the answer you are looking for is: Avid uses QT as its export engine for movies, but within that engine you can pick a wide variety of codecs to use, including AVI if you've purchased the proper codecs for your system.)

    2) Since the DNxHD codec is a full import/export codec loaded into QT you can do this test directly in QT7 Pro. Just open the file in QT7 Pro and then export as a new file using the DNxHD format. Then do it again and again and again...

    i7-5820(x99), 64GB, Win 8.1, GTX 1080ti [view my complete system specs]
  • Tue, Dec 7 2010 10:35 AM In reply to

    Re: Force reencode...

    Thanks for the answer!

    So, Avid doesn't has an intern encoder? Because while exporting via QT I always get this damn gamma-shift while exporting to DNxHD. The black and white-levels stay the same, but the contrast seems to get raised. I searched the whole web for this problem, because I have gamma-problem with the DNxHD code in FCP too. (FCP raises the white levels and lowers the black ones, even when exporting/importing to full rgb with superwhite, wich leads to the washed out image. But this is another topic)

    But there seems to be no real solution for this problem, just some workarounds with converting to Tiff...

    How do you handle the gamma-shift problem?!

    Thanks

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  • Wed, Dec 15 2010 10:46 AM In reply to

    Re: Force reencode...

    Well, if anyone ever got the same problem, here's how it worked best for me:

     

    Internal Transcode to MXF 1:1 (Clip -> Consolidate/Transcode) than transcode back to the desired codec. No gamma-shift here. And no Colorspace change (the before used BMP solution brings two switches yuv>rgb>yuv every step).
    The encoded File has to be picked out of the Avid Media Folder (AvidMediaFiles/MXF..) and copyed to the desired destination.

    Sure, not a slick solution, but it works.

     

    Still: I don't have a clou how to solve this QT-Gamma-shift problems...

     

     

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