DCP randomly cuts off audio for 0.5 seconds.

[accord]

Hello!

I had a DCP made a few days ago and then when I played it on the projector I noticed that it randomly cut off the audio for like half a second and then goes back to normal. The audio itselfs never unsynced and the video was fine. It was just it had these little moments in which the audio choked a bit.

I thought that maybe the problem was on the .mp4 file, but it was working just fine on the parts I noticed the lag. I also thought it could be the projector fault since the subtitles weren't burnt in and maybe our media server was having problems processing them thus causing the lag. But the timestamps of the audio cutoff were consistent. I just now checked the DCP on the DCP-o-Matic player and lo and behold, the problem was there as well. And the timecodes also matched with the projector timecode for the bug.

Additional info: I don't know if it changes anything, but I will throw this here anyway: I made this DCP on the batch encoder and I'm pretty sure I had to pause the encoding at least 2 times because I had to make a VF for another DCP. (I didn't count how many times the audio glitched like this, but it was much more than the times I had to pause the DCP)

[carl]

Can you share the log file from the project where you made the DCP, or email it to carl@dcpomatic.com ?

[accord]

Sure, here it is!

[carl]

Thanks. Is that the complete file? Could you also send the metadata.xml file from the project to carl@dcpomatic.com ?

[accord]

Sorry for the long wait! But yes, it is the complete log file! I had to convert it to txt so I could attatch here. I'm sendig you an e-mail right now, with the same subject as this post! Thank you!

[Carsten]

You can load the audio MXF from the DCP into e.g. Audacity (with the FFMPEG plugin installed). Other audio tools will also play back audio MXFs (VLC). By looking at the waveform in Audacity, you can check wether audio issues are baked in the audio file. If that is the case, something weird happened during the encoding. Could be a bug in DCP-o-matic, or a machine specific issue. We sometimes saw weird issues caused by RAM or CPU glitches.