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IDProjectCategoryView StatusDate SubmittedLast Update
0002079DCP-o-maticBugspublic2021-09-02 22:152023-12-22 22:32
Reporteroverlookmotel Assigned To 
PrioritynormalSeverityminorReproducibilityalways
Status acknowledgedResolutionopen 
PlatformMacOSOS XOS Version10.14
Product Version2.14.37 
Summary0002079: Audio silent in DCP in convoluted case
Description

I have come across a bug in 2.14.x with audio in a rather convoluted case:

I have a DCP which has bad audio that needs to be replaced and also has 2 shots where video needs to be replaced.

I have the following source materials:

  1. DCP
  2. ProResHQ MOV drop-in replacement for shot 1 - with stereo audio
  3. ProResHQ MOV drop-in replacement for shot 2 - with no audio track
  4. WAV file with fixed soundtrack for the whole film (24 bit stereo)

Have assembled a timeline in DCP-o-matic as follows:

00:00:00:00 - 00:00:06:24: DCP (trimmed to 00:00:00:00 - 00:00:06:24)
00:00:06:24 - 00:00:11:20: Replacement ProRes 1 (length 00:00:04:21)
00:00:11:20 - 00:00:29:05: DCP (trimmed to 00:00:11:20 - 00:00:29:05)
00:00:29:05 - 00:00:37:12: Replacement ProRes 2 (length 00:00:08:07)
00:00:37:12 - 00:00:40:00: DCP (trimmed to 00:00:37:12 - 00:00:40:00)
00:00:00:00 - 00:00:40:00: Audio WAV (length 00:00:40:00)

The audio is disabled on the first 5 clips (all channels in channel map switched off). It's only enabled for the WAV file.

i.e. The shots needing replacement have been edited out of the DCP, and replaced with the ProRes files, and the audio is replaced for the entire film with the WAV file.

When DCP is output, it's all worked as expected, except the audio is silent from 00:00:29:05 - 00:00:37:12. The audio from the WAV file is not included during this section.

It seems that DOM is getting confused somehow by the 1st ProRes file having stereo audio, and the 2nd not having an audio track. If I only cut in one of the ProRes files or the other, it works as expected. It's only the combination of the two which produces this bug.

Noticed initially on DOM 2.14.38, but reproduced on 2.14.54. Not reproducable on 2.15.159.

NB Timecodes above are for a cut-down repro case. Actual film was feature-length.

Steps To Reproduce

Carl, I'll email you the files required to reproduce.

Additional Information

This is may seem like an unlikely case, but actually we do this kind of thing quite often. It's not uncommon to have a source DCP and have to replace some shots with fixes, or replace audio with an amended soundtrack.

This is first time we've had problems with it, probably as this is first time when the drop-in replacement files are inconsistent in some of them having audio and some not.

I don't know how far off 2.16.0 is now, so whether it'd be worthwhile fixing in 2.14.x in meantime?

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overlookmotel

2021-09-02 22:42

developer   ~0004524

By the way, was scratching my head about this while trying to diagnose this problem: What are <FirstVideo>0</FirstVideo> and <FirstAudio>0</FirstAudio> for in metadata.xml? I can't figure out the logic of where they appear and where they don't (despite the obvious-sounding names).

overlookmotel

2021-09-02 22:43

developer   ~0004525

Damn you Mantis garbling my markdown! Hopefully you can divine what I'm talking about...

overlookmotel

2021-09-21 02:29

developer   ~0004545

I just hit this bug again, with a different case.

In this new case, timeline contained:

00:00:00:00 - 00:00:02:00: ProRes file
00:00:02:00 - 00:10:02:00: ProRes file
00:00:00:00 - 00:10:12:00: 6 x mono WAV files (5.1 mix)

Both ProRes sections is same file used twice. File is 10 minutes long exactly. 0-2 secs in timeline is the first 2 secs of the file, then it's followed by the whole file. i.e. Whole file, but with first 2 seconds repeated twice.

ProRes has embedded stereo audio. That audio is disabled (gain set to 0dB, and all channels disabled) in both uses of the ProRes. Idea is to use the 5.1 mix only.

Reason for this odd timeline: 5.1 audio mix starts 2 secs before picture and continues on for 10 secs after picture ends. The opening picture is a static dark background. So I repeated the first 2 secs of picture to cover the gap at start where we have no matching picture for the audio (rather than leaving a gap at start of timeline which would result in 2 secs black followed by the dark background coming in suddenly).

In the output, the audio from the 6 WAV files plays throughout until 00:10:02:00 (the point where the video file ends) but then abruptly cuts out before the end of the 5.1 WAVs sound. The DCP has length 00:10:12:00 as intended, but last 10 seconds are silent.

I don't know if it's relevant that, as in original case reported above, I'm using the same video file more than once in the timeline.

If there's any variants I can try to help narrow down the potential cause of this bug, please let me know.

Bug History

Date Modified Username Field Change
2021-09-02 22:15 overlookmotel New Bug
2021-09-02 22:42 overlookmotel Note Added: 0004524
2021-09-02 22:43 overlookmotel Note Added: 0004525
2021-09-21 02:29 overlookmotel Note Added: 0004545
2023-12-22 22:32 carl Status new => acknowledged