[Qtractor-devel] Qtractor: imported mp3 / internal tempo go out of sync when moving the playhead

[Nikita P <the...@gm...>]

Qtractor version: 0.9.3.25git.337cf1

Repro steps starting from an empty project:
* add an audio track
* import an mp3 file that has rhythmic content and place it into the track
* set project BPM and tempo to the same amount as the mp3
* (optional) fine-tune the audio clip position to synchronize the beats
* turn on the metronome

If I click play when the playhead is at the beginning of the project,
metronome and the audio clip will be in sync. They will continue being
in sync until the end.

If I move the playhead further along the timeline and then click play,
metronome clicks and the mp3's beats will be out of sync.

I use the audio metronome, not the midi one.

Here's a 120 bpm click track I created in Audacity you can use for
testing: https://www.dropbox.com/s/skcc6mhjp5aeb9q/test_click_track.mp3?dl=0

It seems to be an issue with playing back mp3 audio files. The same
click track exported from Audacity as a WAV and then imported into
Qtractor works fine. Tried ogg, and it was also fine.

Additionally, when playing with the playhead at the start, the
uncompressed/ogg click track is more in sync with Qtractor's metronome
than the mp3 one.