Latest post Wed, Mar 23 2011 7:41 PM by DLpres. 4 replies.
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  • Thu, Sep 30 2010 4:03 PM

    • paranerd
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    Sad [:(] MC5 - Exporting AAF with multiple frame rates kills audio handles

    Hey all!  I did a search of the forum and I'm surprised to not find a thread on this issue.  I'm mainly a dialogue editor with Pro Tools, so I apologize for any MC5 ignorance I have.

     

    If you work with multiple frame rates in MC5, let's say 29.97DF and 23.98, and export an AAF session with a 29.97DF frame rate, all the 23.98 footage will be rendered with Motion Effect.  This essentially kills all the handles on the audio clips and renders all Avid volume changes into the rendered audio when I open the AAF in Pro Tools.  The work around we developed was exporting two AAFs: one in 29.97DF and another in 23.98.  I would then open and combine both AAFs in a single session and discard all the "motion effected" clips.  For a 46 minute show, there would be a discrepancy of 4 frames by the end and I would simply realign everything manually.

     

    However, I've come to another problem that I can't readily fix with the 2 AAFs workaround.  In the timeline, there is footage shot on Red and on "VariCam" (this is what my video editor called it, I don't know what it is), both at 23.98.  The Red footage doesn't get "motion effected," but the "VariCam" footage does in the same 23.98 AAF.  I don't understand how to easily fix this problem as I can't export an 23.98 AAF without "motion effecting" the "VariCam" footage.

     

    I know Avid has known about his bug for a while and I'm surprised it hasn't been dealt with it yet.  The dual AAF workaround wasn't ideal, but at least I could get handles and work done.  In this case, I would have no handles on all "VariCam" footage which isn't something I want to work with.

     

    Thanks!

  • Mon, Oct 4 2010 1:52 PM In reply to

    • paranerd
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    Re: MC5 - Exporting AAF with multiple frame rates kills audio handles

    No one has any insight or even come across this problem?

  • Mon, Oct 4 2010 2:20 PM In reply to

    • dmfreeman
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    Re: MC5 - Exporting AAF with multiple frame rates kills audio handles

    Just a "Shot In The Dark", but have you tried doing a video and audio mixdown, replace your timeline files with the mixdown files and export with that?  You also may need to do a QT reference file also.

    Denny

    Media Composer 2019.6, BCC Continuum 12.5, , Boris Red 5.6., Asus P9X79 Pro Motherboard with Intel 3930K Processor. 32 gigs DDR3 ram, Windows 10 Pro 1803... [view my complete system specs]
  • Tue, Oct 5 2010 2:00 PM In reply to

    • paranerd
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    Re: MC5 - Exporting AAF with multiple frame rates kills audio handles

    dmfreeman:

    Just a "Shot In The Dark", but have you tried doing a video and audio mixdown, replace your timeline files with the mixdown files and export with that?  You also may need to do a QT reference file also.

    Denny

    Thanks for the reply!

     

    Correct me if I'm wrong, but wouldn't doing an audio mixdown simply mix down the audio in the timeline to a stereo (or mono) mix file?   I think that would assure the elimination of audio handles similar to the "motion effect" problem.

  • Wed, Mar 23 2011 7:41 PM In reply to

    • DLpres
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    Re: MC5 - Exporting AAF with multiple frame rates kills audio handles

    I experienced this recently, and was also surprised by how little attention this bug (or "mis-feature") got.

    I dug in, and what basically happens is that Avid applies a "Motion Adapter" effect to clips that differ from the project's frame rate. Great for video, but unfortunately it tracks also to audio. I doubt it actually does anything, but the resulting rendered media loses the clip name and the handles.

    According to Avid and a PT forum post, Pro Tools 9 solves the problem. I can only assume that the AAF still contains both the original clip and the Motion-Adapted render, and PT9 knows to pick the right one.

     


    In the absence of PT9, I know of two workarounds:

     

    I Transcoding (thanks to Adam from Avid Symphony support)

    1. Open the sequence in Symphony or MC 5 (this is not supported in v4).
    2. Transcode it to 16bit. Agree to convert the clips.
    3. Transcode the result to 24bit. Agree to convert the clips.
    4. Export the AAF as usual.

    Basically if Avid sees a need to transcode the clips (different bit depth, sample rate etc.) it will also rewrite the frame rate and hence solve the problem. The two transcodes are simply to ensure everything is treated, the downside is losing 24bit quality. There may be more efficient ways to avoid unnecesary transcodes in your project.

     

    II Multiple AAFs (as mentioned by paranerd)

    1. Export AAF.
    2. Choose the sequence and choose Clip->Modify->Format
    3. Set the format to the other frame rate (e.g. NTSC 30i instead of 720p60)
    4. Avid creates a new modified sequence. Export it as another AAF.
    You should need an AAF for every frame rate present in your sequence (24p, 30i, 60p).
    5. Import both AAF's into Pro Tools.

    Each AAF will have its 'own' clips good, and the mixed-rate bad. This avoid unnecesary conversions but you're left with having to manually reconcile the multiple AAFs into one good session.


    I was musing about a 3rd way, if only I could modify the FPS metadata in the actual MXF files, then relink to 'compatible rates'. There are at least 2 open-source MXF SDK's out there, but I don't have the time/expertise to write the code.

     

     

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