Latest post Tue, Aug 21 2018 3:48 PM by Erik. 3 replies.
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  • Tue, Jul 31 2018 11:15 PM

    • Erik
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    • Austin, TX
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    What's the secret to MC and DNxHD/DNxHR with alpha

    Historically for graphics with alphas such as animated lower 3rds I've always created them in Adobe After Effects and then rendered them out using the Animation codec and straight alpha. These import perfectly into MC.

    Lately with larger frame sizes like UHD and consistency even with HD, I've been using DNxHD/DNxHR instead of animation in more of my workflows when exporting graphics out of AE. Within the codec configution within AE, there is an option for including an uncompressed Alpha channel.

    When rendered out they work perfectly with After Effects. However, no matter what combination of render settings and MC import settings, MC does a horrible job of working with these DNxHD/DNxHR files that include alphas. It's not like it doesn't recognize the alpha... it knocks out some of the image while leaving other traces around or shows blocks of the background any number of strange things.

    What is the secret combination of things to get a clean alpha using Avid's codecs and importing these files into MC?

    MC 2018.4 Dell Precision 7710 mobile workstation, 64GB of memory, Xeon E3-1535M v5 @2.9Ghz, Nvidia Quadro M5000m. Running Win10 64bit. MC 2018.5 Asus... [view my complete system specs]
  • Fri, Aug 3 2018 2:58 PM In reply to

    • Erik
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    Re: What's the secret to MC and DNxHD/DNxHR with alpha

    So does nobody import Avid DNxHD/DNxHR media with alphas? 

    MC 2018.4 Dell Precision 7710 mobile workstation, 64GB of memory, Xeon E3-1535M v5 @2.9Ghz, Nvidia Quadro M5000m. Running Win10 64bit. MC 2018.5 Asus... [view my complete system specs]
  • Thu, Aug 9 2018 12:29 PM In reply to

    • knejmann
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    Re: What's the secret to MC and DNxHD/DNxHR with alpha

    I've just done a quick test with a moving text from After Effects to Media Composer.

    Normally I set Import Setting --> Image --> Alpha Channel --> Invert on import - that works fine with most file formats as most software "likes" white in the alpha channel to equal opaque. However in the case of DNxHD the setting must be Do not invert. I guess it's somewhere in the DNxHD specs that black = opaque(?).

    Have you tried that setting?

    Media Composer 8.2.11 (some with Symphony option) - Windows 7 - HP Z420/Z820 (Nitris DX), Lenovo W540 etc. - Interplay and ISIS7000+NEXIS storage - Avid... [view my complete system specs]

    Kåre Nejmann

    Danish Broadcasting Corporation - DR
    Aarhus, Denmark 

  • Tue, Aug 21 2018 3:48 PM In reply to

    • Erik
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    Re: What's the secret to MC and DNxHD/DNxHR with alpha

    knejmann:

    However in the case of DNxHD the setting must be Do not invert. I guess it's somewhere in the DNxHD specs that black = opaque(?).

    Have you tried that setting?

     

    I think I have, but it might be worth looking at it again. Avid sort of goes my the old film transparency rule where white areas of the film frame would be transparent and then black areas would be opaque and shades of grey in between are semi-transparent. Now with digital, it's commonly the oposite way around where white areas denote opaque areas and black are transparent. Hence the invert option in MC. 

     

    MC 2018.4 Dell Precision 7710 mobile workstation, 64GB of memory, Xeon E3-1535M v5 @2.9Ghz, Nvidia Quadro M5000m. Running Win10 64bit. MC 2018.5 Asus... [view my complete system specs]
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