Ignore audio from video file

[lcanau]

Hi, first time poster. Great software, thank you.

There are advanced settings that allow to "ignore this content's video and use only audio...", so I assume there's no option to use only the video.

I got a QT ProRes file with 6 channels but it seems to have been exported with discreet channels, it's not recognized as 5.1., DCP-o-Matic only marks the centre channel on the audio tab.

DCPomatic1.png

I wondered if there would be a way inside DCP-o-Matic to map the 6 channels properly, but I assume it's something that should be done properly before the DCP creation.

I can export a new file with the channels properly mapped, but it would be great if I could just export a 5.1 WAV file instead of another quite heavy video file, and to use the existing file, ignoring it's audio.

DCPomatic2.png

[Carsten]

You can just 'unmap' the one audio track that comes with the video, then load the multichannel WAV file and map it properly. Deselecting all audio tracks within an interleaved video/audio file is the same as 'ignore audio'. You will also recognise this in timeline view.

Weird - DCP-o-matic SHOULD show the other discrete channels in the audio matrix. Are you sure you can not scroll lower to see them?

Can you show us a more complete screenshot of the matrix when that file is loaded? Also, right click on the content in the list and choose 'properties'.


- Carsten

[lcanau]

There's nothing below, to scroll lower. The Quicktime inspector identifies the six tracks:

ProRes_QT.png

Both Windows properties and properties inside DoM seem to identify only one track.

ProRes_Windows.png

DoM doesn't identify tracks in the properties only the sample rate.

ProRes_DoM.png

I exported this ProRes from DaVinci Resolve into a DNxHR Quicktime with multichannel 5.1 audio which would have solve this issue, but I'm getting another problem. I'll continue in a new message because apparently I can't add more images to this post.

[Carsten]

Can you upload the ffprobe.log file from your project directory? It shows more details about the video and audio formats that have been identified when adding the content.

[lcanau]

I can upload the file, I just didn't want anything online that would identify the project. Can I just remove filename, duration...? Anything else on the file? Or would it be enough to paste the part with the Streams? I would like to understand the issue - and also how to not use a soundtrack from a file - but in any case I made the DCP from another file, so while the issue was not solved the task is done.

The other issue I faced with the exported DCP was that the audio was sort of garbled in the Player. Not sure if "garbled" is the proper word; it's not a bit this or that or just plain distorted, but more or less unintelligible. It's like my headphones have an issue or the audio is not being decoded properly. Opening the audio MXF via VLC didn't replicate the issue, it sounded normal. I saw a recent thread about audio issues with the player and uninstalled the current version and downloaded 2.16.56. It now seems normal, thankfully.

I tested another DCP with 5.1 audio and it sounded normal even with the current version of DoM, so that doesn't happen with all DCPs.

Any Mac to Windows variables with these issues, maybe? Most of the DCPs I make use image sequence plus 6 mono tracks I'm provided with. I used video files before without issues, but maybe never a ProRes, I'm not sure.

I was also worrying the DCP was showing 16 audio channels instead of 6 but I see from other threads that's how it's supposed to be in recent versions.

[Carsten]

No problem to erase filename or any other hints.

[lcanau]

OK, I'm attaching the log, thank you.

[removed]

[Carsten]

Strange. ffprobe DOES see the 6 individual streams.

This is how this would look like with two streams:

Bildschirmfoto 2023-06-07 um 14.25.24.png

In your case, with the initial Prores file there would have been 6 - you would have to scroll down to reach them, but it should have been no problem to map them to DCP channels.

[carl]

I'm not sure I'm following correctly here ... are we just talking about how the auto-mapping of this file isn't working in DCP-o-matic? Or is there some bigger problem?

[Carsten]

His original Prores carries six separate streams - ffprobe shows them, but DCP-o-matic will only show the first stream/channel in the matrix (first screenshot in this thread).