Freezing during export to audio if video attached to multiple flows

I found a workaround for this issue, but am posting this here as both a bug report and guidance to others who run into the same problem.

I found that Dorico 3.0 would consistently freeze midway during an export to WAV. (Always at the 26% point for some reason.) A freshly-created Dorico project didn’t have the same problem and would export fine.

The project had two flows, both of which were attached to the same video file. I tried detaching video from one of them, at which point the export to WAV resumed working correctly.

So: it might be the case that D3.0 has trouble exporting to WAV when more than one flow has video attached.

We also had a report where audio from video would not play back at all in Dorico 3. How about your setup, does the audio from the video can be heard during normal playback?
I could imagine that the export fails if the audio from video is not around.

On the other hand, would it be possible that you provide us the project together with the video, so we can try and debug it ourselves?
Of course, confidentiality is fully guaranteed from our side.
If you consent, please tell us the size of the data so we can negotiate a medium for transfer.
Many thanks in advance.

Sadly, I’m contractually prohibited from sharing the video in question. Here’s some info that might be useful:

  • The audio from the video plays fine.
  • The video is fairly long (half a gig if I remember correctly)

I might suggest trying to replicate this with an arbitrary video, attached to two or more flows. (Or multiple videos attached to two or more flows.

Would you be able to send us the project file (even if you need to delete all the notes in it then it would be useful). I haven’t been able to reproduce this.

The project file as a zip is too large to attach here. (3.2 mb) Where can I send it?

Please send to ‘p dot walmsley at steinberg dot de’. Thanks

Huzzah! This is apparently fixed in Dorico 3.0.10!

Non-huzzah! Instead of crashing, Dorico now outputs an empty audio file.

I can only get audio export to work if I detach all video files from all flows.

Help?

Did you send the project and the video file to Paul as requested?

Previously yes, when the problem was that Dorico 3.0 was crashing during export. The latest response was “We’re still hunting around for possible causes”. I’d hoped that some work was done on this in 3.010 since at least the crashing has stopped.

We haven’t managed to isolate that particular export problem yet, unfortunately.

Paul, does the fact that the problem has changed (exporting blank audio) offer any clues?

I think this may just be a different manifestation of the same issue. It’s some strange quirk with the attachment positions of the video. They look absolutely fine, but for some reason the audio export goes crazy when trying to work out when to export them. If you temporarily detach the video files, does the audio export complete successfully?

Yes, that’s my workaround. But I believe I have to remove video from all flows to bounce audio from any of them.

And so far I have had to customize the video parameters, so you may be onto something in suspecting that the attachment position may be involved!

Update: I seem to be having luck exporting audio when the attached movie is a .mov file (as opposed to .mp4). Perhaps the problem is codec-specific?

I don’t think it’s specifically down to the codec. The problem is in the code that works on the extracted audio track. I suspect that by re-encoding it, the audio track has a very slightly different size or timestamp, and that’s just on the threshold of triggering this bug.