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CPU freeze at playback after cutting/deleting/duplicating audio strip
Closed, ResolvedPublic


--- Operating System, Graphics card ---
Arch Linux 64-bit
Nvidia GTX 660M 2GB
Intel® Core™ i7-3630QM CPU @ 2.40GHz × 8

Audio Codec:
48 Khz 5.1 AC-3 sound at 448kbps

Video Codec:
BDAV / AVCHD at 1920x1080i, 25 FPS, with ~15Mbps Variable Bitrate (proxied)

--- Blender version with error, and version that worked ---
Version with issues: 2.60 - 2.66.6
Version with better performance: 2.56-2.59

--- Short description of error ---
I experience a 5 second freeze of the blender user interface similar to attached picture whenever I cut (K), delete (X) or duplicate (Shift+D) an audio strip in my movie. The movie itself is proxied with Record Run No Gaps and with q90 at 25% and there are no issues with cutting it. Moving the left and right handles instead of cutting does not give such a freeze. The problem seem to be worse, the more strips there are present on the timeline.

--- Steps for others to reproduce the error (preferably based on attached .blend file) ---
Download this blend file: (couldn't attach it sry)
- Open test.blend.
- Perform playback (Alt+A).
- Right-click on a random audio strip.
- Shift+D to duplicate it.
- Shift+A to perform playback.

You should now get a freeze.

Related forum post:*action*-gt-Alt-A

Event Timeline

Will check on this after the release (release shall happen within few days and we're currently only fixing crucial bugs/regressions, this bug happend for quite a few versions already).

Wasn't able to fully reproduce the issue -- meaning first time i'm starting playback there's indeed a time lag, caused by FFmpeg initialization for all the strips. But duplicating strips and cutting them didn't seem to cause any further slowdown.

Joerg, do you think it's possible to avoid initialization of all the strips when starting playback or that'd lead to sound lags later?

I just wanted to inform you that I have found that extracting the audio from the video files in PCM format seem to solve the issue (though I run out of RAM quickly). I don't have technical knowledge about this but perhaps audio proxies could help this issue.

In any case thank you for looking into this Sergey!

Hi, sorry it took me so long, but I was pretty busy recently. I could reproduce the bug and fix it in revision 57597. Now the hang only happens once, but that's necessary as the strips all get initialized with ffmpeg. I don't think it's a good idea to do that later and it has to be done only once now when the file is opened as this bug is fixed.


Joerg Mueller (nexyon) changed the task status from Unknown Status to Resolved.Jun 20 2013, 9:49 AM

Thank you very much for fixing this bug, Joerg! I will make sure to test this in particular once the bug arrives in a stable Blender release. :-)