Bug 388065

Summary: Audio out of sync (sampling frequency)
Product: [Applications] kdenlive Reporter: mau <b-misc>
Component: Rendering & ExportAssignee: Jean-Baptiste Mardelle <jb>
Status: RESOLVED FIXED    
Severity: normal CC: b-misc
Priority: NOR    
Version First Reported In: 17.08.3   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description mau 2017-12-20 10:54:03 UTC 
Hi

I guess I've found a bug in kdenlive, using the 17.08.3 AppImage.

In my project most of the clips have audio with 48000 Hz sampling frequency, but some of them have only 44100 Hz. In the timeline everything is shown and played back correctly, but when I render my project I get audio and video significantly out of sync.

I could trace it back to the different sampling frequencies. If I convert these 44100 Hz files to 48000 Hz and replace them in the timeline, I can render my project correctly, audio and video are in sync.

Reproducible: always

Steps required:
1. mix 44100 Hz and 48000 Hz audio files in project
2. find that audio and video are in sync in the timeline
3. render project
4. find that audio and video are not in sync in the rendered file
5. replace 44100 Hz files by 48000 Hz variants, render and find result in sync
Comment 1 mau 2017-12-20 12:58:12 UTC 
Additional info:
The 44100 Hz clip begins correctly, but runs too fast so it ends before it should. But note as well that all subsequent audio will be moved towards the beginning as well, yielding to video and audio out of sync for the remainder of the movie.
Comment 2 mau 2017-12-31 07:50:19 UTC 
Problem is fixed with 17.12 release, probably related to the drop of avresample (Bug 386932).