Audio wave form always showing track 1 of source video [Ver 19.09.14]

Steps To Reproduce

  1. Create a MKV video containing 2 audio tracks (e.g. using OBS: [1] Desktop Audio, [2] Mic)
  2. Put that video on the timeline
  3. Go to the properties > “Audio” tab and select “Track 2”
  4. Choose “Rebuild Audio Waveform”
  5. Choose “Detach Audio” on the context menu of the timeline object.
  6. Choose “Rebuild Audio Waveform”

Actual Result

  • After step 3: The timeline is still showing the wave form of Track 1
  • After step 4: No effect
  • After step 5: The detached timeline object is showing the wave form of Track 1 (although track 2 is playing)
  • After step 6: No effect

Expexted Result

*The timeline objects should show the wave form of track 2 of the source video file.

Assumptions

The fact that “Rebuild Audio Waveform” has no effect is evidence that it’s not a refresh problem, but the wave form drawing routine is hard coded to use track 1.

Workaround

I used MkvToolnix to demux the 2nd audio to a separate file and put that on the timeline.

Hi and welcome @derVodi,

perhaps it is caused by your OBS.
If you use two different channels in OBS and you set it in “mkv”, you will be advised by a warning, that special codecs do not support multiple audiotracks per record.

I can confirm this.
Windows 10, Shotcut Version 19.04.14
The audio waveforms take on Track 1 audio and does not change.
Track 1


Track 2
shotcut_2019-09-18_08-42-44

Detached Audio, Same Project
Track 1


Track 2

This is fixed for the next version 19.10.
It will not automatically work on existing projects because I did not want to invalidate everyone’s caches. For existing projects with incorrect waveform on alternate audio track, you need to right-click and choose Rebuild Audio Waveform and save the project for it to relocate the audio level data from cache.

1 Like