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Glitched export w/ Pr and M1 (and workaround solution)
TL:DR
Mixed framerates w/ alpha channel seem to generate glitched exports. Workaround is to convert raw footage to same framerate as sequence.
Computer specs:
2022 Mac Studio, M1 Max, 32 GB, Monterey 12.5.1
App specs:
Pr 22.6.2
Me 22.6
Ae 22.6
Sequence specs:
1080, 29.97, ProRes HQ
Problem:
Random glitches on render or exports, but seemingly only around graphics w/ alpha channels.
Footage:
59.94 h264 .mov (a rewrap of C100 Mkii)
Graphics:
29.97 MOGRT w/ alpha channel
Attempted solutions:
Run Pr and Me in Rosetta
Run Pr and Me in Software Only mode
Reset Sequence to 59.94
Redo MOGRTs w/ M1 ver. of Ae
Redo MOGRTs as 59.94
Export ProRes 4444 of graphics out of Ae
Change Time Interpolation on the 59.94 footage
Working theory:
Glitches result from Pr (on an M1) not knowing how to deal with throwaway frames in the framerate conversion when there is an alpha channel on, say, Track 2. May or may not be codec specific (i.e., h264).
Workaround solution:
Transcode footage as ProRes HQ at 29.97
Commentary:
Location of glitches random with each render/export. Have seen the same glitches from other M1 computers (e.g., laptop and 24”). In my searches, seemed to be a lot of chatter about a year ago of this problem. And most of it seemed centered around h264. The most common solutions were to run Pr in Rosetta and/or update to the latest beta ver. of Pr. Rosetta solution doesn’t work, and we’re well past the beta ver. suggested in those solutions. But those solutions did seem to work for some, so as usual, YMMV.
The “seeming” workaround solution for me right now is still early in its implementation, so we’ll see with future renders/exports. Downside to this is how much storage it eats up. Hoping another workaround solution presents itself, or (obviously preferable) hoping future updates to Pr and Me can fix this, because what I’ve come up with so far isn’t a sustainable workaround (both in terms of workflow and storage).
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2 Replies
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Update:
I’m beyond frustrated. First thread was about simply documenting what I was experiencing–for posterity–as much for myself as for anyone else doing searches. Wasn’t really asking for any help unless it sounded familiar to someone. But now I am–some kind of clue, or something.
I noticed the other day the glitch (or better described as frame warping) in the Source monitor. Meaning, out goes the theory that it is related to graphics, alpha channels, framerate conversion going from 60 to 30 in the timeline.
Current theory? May have something to do with the way Premiere interprets the h264 codec, and specifically the 59.94 version of it. Maybe? Because I’m not seeing this anywhere else (e.g., FCP, Quicktime, Finder).
Testing of other outputs at 29.97 doesn’t seem to do it. At least as of right now in my small batch of testing. Our group has done thousands of videos over multiple years with the same workflow, and this issue has only popped up with the introduction of Apple Silicone into our group. And we’ve seen this across the laptop, iMac, and Studio. Same frame warping of footage. And it’s random. As in clearing the cache will make it disappear from one section of the footage, only to have it show up in another section.
So again, any clues to solving, or confirmations of the issues, would be helpful. Thanks all!
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Update #2 (for those following this). I’ve now posted a bug report to Adobe. Tagged on to another thread dated 2/11/22 reporting playback and export glitches off of a NAS. Not my problem exactly, but there does seem to be some type of issue with Adobe trying to nail-down all of the nuances of working with myriad footage types and the M1 architecture.
Oh! And have upgraded to the latest version (23.0.0, Build 63), and though the issue remains, I am now seeing the GPU and all of the cores get maxed out on exports. So definitely some performance improvements, just not in this specific use case.
And lastly, attaching a screenshot example of the glitching. Again, same issue whether playback or export. (And those are hands clasped together, in case you’re wondering.)
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