Change Tempo Effect

I think I’ve found a bug in the execution of this effect (see attached screenshots). The overall length has changed to the required 3,600 seconds (give or take) but the clip EPR-RRU 1 20 has been deleted. I’ve experienced this on several occasions.

The obvious question is: What is special about clip EPR-RRU 1 20?

If you can create a test case where the “special” (deleted) clip is very small (a few thousand samples or less), then my guess is that we will be able to find an invalid sample in it.

It is not practical to attempt sample by sample testing of a project with tens of millions of samples, but if you can produce a test case with a small project (possibly by deleting parts of the project to whittle it down), then we can start searching for the cause.

Which version of Audacity are you using?

Are you using the “high quality” setting in Change Tempo?

I assume that it is the same clip that is being deleted each time - is that correct?

If you Undo the Change Tempo effect, and then try to play the clip that was deleted, does it play correctly?

Did you check to see if the entire project played correctly before applying the Change Tempo effect?

  1. v.3.1.2.
  2. Not high quality.
  3. Yes, the same clip when it happens, which is not always.
  4. Yes, it does play correctly.
  5. No, but I shall.

No worries, I’ll work around it.

Thanks for the answers.

Do other effects apply correctly?
Does Change Tempo with “high quality” enabled have the same problem?

Pleased to hear that you can work around it, but it would be very useful if we could find the cause of the problem. I’ve not been able to reproduce the problem here (yet), but it’s unlikely to only be happening to you.

I haven’t tried high quality because Audacity is resource-hungry (I often close other apps, sometimes raise its CPU priority) and I get enough unrecoverable ‘hangs’ as it is.

I don’t use many effects - Change Tempo, Compressor and Normalize - so I’m unable to comment on others. The issue isn’t constant but when it happens, repeated applications result in the same clip being deleted. I work around it by applying the effect individually, just takes longer. I’m inclined to agree the likely cause is data corruption but why an entire clip’s lost is beyond me. After 35 years at the IT coalface I shouldn’t be surprised at anything. :slight_smile: