https://bugs.kde.org/show_bug.cgi?id=504579
Bug ID: 504579
Summary: Audio thumbnail waveform doesn't match audio for
longer audio-only file
Classification: Applications
Product: kdenlive
Version First 25.04.1
Reported In:
Platform: unspecified
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: Monitors & Playback
Assignee: j...@kdenlive.org
Reporter: k...@veronicaexplains.net
Target Milestone: ---
SUMMARY
After importing a long audio file (wav in my case), the audio thumbnail which
shows the waveform drifts from the audible sound itself. After a period of time
the audio is quite out-of-sync from the waveform. This was not present in
Kdenlive 24.x before rebuilding the audio thumbnail process.
I have published a video outlining my observation of this and comparing between
24.X and 25.X here: https://youtu.be/0iTfcZJwKSk
I can provide long audio samples on request, I've noticed that this isn't
observable until about 20 minutes into the waveform or so, as the video
mentions by 40 minutes it's quite pronounced.
Notably, if I ignore the waveform (audio thumbnail) and just edit "by ear", and
then render that segment, the rendered audio sounds like what I'm hearing, and
*not* what the waveform (audio thumbnail) looks like. Which makes me think it
has to do with the rebuilding of the audio thumbnail engine.
I've tried audio files generated from multiple programs (Ardour, Audacity,
Bitwig) and various import formats. Confirmed the same bug on various machines
(Debian Trixie, Pop!_OS, Fedora).
STEPS TO REPRODUCE
1. Launch AppImage of Kdenlive and import a long audio file (at least 30
minutes or so)
2. When Audio Thumbnail is generated, scroll to the end of the long audio file
3. Compare audio in the thumbnail with audible audio
OBSERVED RESULT
The audio heard is not in sync with the waveform, it feels like it's 5-15
frames off.
EXPECTED RESULT
The audio heard should be in sync with the waveform.
SOFTWARE/OS VERSIONS
Windows: n/a
macOS: n/a
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: Debian 13 with GNOME, Fedora 42 with GNOME, Pop!_OS 24.04
with COSMIC
KDE Plasma Version:
KDE Frameworks Version:
Qt Version:
ADDITIONAL INFORMATION
KDE Flatpak Runtime 6.9 (observed via Flatpak)
Thank you so much!
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