PRORES 4444 stutters on reverse playback

Bug Reports
1

Steps causing the bug to occur

  1. Place a clip of 4444 ProRes in composition.
  2. Set playback style to mirrored loop
  3. Set optimisation for random
  4. Clip stutters when played back reverse

Have you found a workaround?

Yes, I simply create a mirrored loop that is rendered together as a media stem

Other notes

  • How severely does this bug affect you? It’s annoying but I can work around it.
2

I see what you mean about reverse playback of ProRes4444 stuttering.

Reverse playback is very resource-intensive since it requires a lot of seeking (a surprisingly expensive operation). It’s good that you’re using an intra-frame codec for reverse playback, which cuts down on some of the work, but there’s still a lot of processing (partially due to limitations in the underlying OS X libraries for video playback). So there’s a limit to how big of movies your system will be able to play in reverse in real time.

I’d recommend just the workaround you’ve already found, rendering the movie backwards so that Vuo can play it forwards.

3

The strange thing is @jstrecker, I’m using a super fast SSD for video footage, CPU usage isn’t going crazy either. Maybe Sierra will bring better AVFoundation performance?

4

If the implementation of AVFoundation only uses one processor (not taking advantage of multiple cores through multithreading), then your CPU usage across all of your cores might not be that high.