DCP-o-matic doesn't appear to recognize 5.1 mapping from MOV

[Sky]

Searched the forums thoroughly for similar topics. Nonetheless, please link to another thread if I'm repeating an age-old question

I've been supplied a MOV to create a 5.1 surround DCP. When I add the file to the DCP-o-matic project and analyze audio, only the center channel appears on the audio map. I assumed there was an issue with the source file's export, but after going back and forth with the person who made it, I'm not so sure (that is, they confirmed I received the right file, which was tested by them and confirmed to have the correct mapping, etc.).

Some context: In an earlier workaround attempt, I used only the video from the MOV (turned off the center channel on the MOV in DCP-o-matic to remove the audio) and used the WAV stems supplied by the sound designer. That seemed to work fine, but there was (evidently unintended) resonance in the cinema, and the sound wasn't particularly immersive besides. The filmmaker confirmed with me that the sound didn't meet expectations.

I did confirm on the sound processor's monitor, its software, and an external sound monitor that the surrounds were receiving signals. Given that our cinema plays features with 5.1 or 7.1 mixes that sound great all day every day, I don't have reason to believe the problem lies there.

That leads me to believe either A) something invisible to me went awry in using the stems, or B) the sound mix isn't great. I'm working with some seasoned pros here, so I'm inclined to believe the former.

With that, I'm trying again with the MOV to see if we get the same results, but I can't seem to get past this issue with the audio mapping.

Happy to supply any information I can to help troubleshoot. Thanks, y'all.

[carl]

Can you show a screen shot of how the DCP-o-matic audio tab looks when this MOV file is selected?

[Sky]

5.1 input mapping to center.png

[carl]

Thanks. DCP-o-matic unfortunately does not do a great job of auto-setup on files like this. A lot (maybe even most) files would have a one or more audio "streams", with 6 channels (perhaps each stream would be a different language).

Here you have 6 streams, with 1 channel each. Assuming your MOV channel layout is the L, R, C, Lfe, Ls, Rs you need to click the matrix until it looks like this

fixed.png

Also that level is high, so I would suggest setting the gain to -10 or so.

[Sky]

Thanks, Carl. I'll give this a shot and report back.

[Carsten]

As for volume - you should perform a full loudness analysis and look at the LUFS and/or LEQ values. Peak values near zero may be okay if loudness is within an acceptable range.

When your file has audio arranged in 6 individual streams (as opposed to a single stream containing 6 channels), you need to apply all audio level changes to all streams identically.

[Sky]

Thanks for the volume tips. I do always drop it to -6dB, which works well in our houses. I should look more closely at LUFS, though.

This solution worked for me. Thanks, Carl and Carsten.

[Carsten]

LUFS around -20 or LEQ(m) around 80dB should be the right values to aim for.