DCP-o-matic converts 5.1 multichannel mix to 6 separate monos?

[Gorkem Sifael]

Hi,

I exported my film in premiere pro in prores4444 and used a 5.1 multichannel mix that was given to me by the audio engineer. I made my DCP out of it by using DCP-o-matic. It showed all 6 channels in the correct places with one full green box in each row and column, and I selected (6 - 5.1) in channels as it was detected by default. But when I went to the theater to test it, it only played through the speakers on top of the screen (nothing from the surround speakers).

When I import the mxf audio file created by DCP-o-matic into premiere pro to check, I see it created 6 separate mono channels. But I was assuming that the DCP to keeps the 5.1 multichannel mix when creating the DCP? Or is this how it should be? I am afraid this is the cause of the issue. I checked the prores source file I exported has a multichannel mix, so it is definitely changed when I make the DCP.

I just made another export in premiere pro, this time I used single stems for each channel and panned them myself in case the multichannel mix given to me did not have that done correctly. But yes when I make that into a DCP, it comes out as 6 separate mono channels. Also just want to note that my LFE channel has no sound because the film doesn't have such frequency audio.

Now I have one more chance to try at the festival's theater tomorrow so I just want to make sure that I take a worthwhile shot before I give into watching the film in stereo/through the center speakers of the theater. If you can please share your knowledge and experience, I would be grateful.

[carl]

When you loaded the MXF into Premiere Pro, did you see audio on each channel (except LFE)?

[Gorkem Sifael]

Hi Carl,

Thanks for getting back to me. Yes, I do. All of the channels in the MXF file are filled with the correct audio (except for LFE that is empty anyway). But it is not one track with 6 channels (multichannel mix). It is 6 separate mono channels. Is that normal for a DCP?

[carl]

I guess it's more about Premiere presents the channels. The MXF contains 6 channels of audio; if you see them, I think they are almost certainly present.

What's strange is why you're not hearing anything out of the other channels. Perhaps the order is wrong. Is it possible to make the MXF available for download somewhere, so I can check? Alternatively, perhaps you can share a screenshot of Premiere with your MXF loaded. Do you know the order of the channels in the 5.1 mix you got from your engineer?

[Carsten]

That's normal. If you open the audio MXF in a capable programm and every channel is populated with the proper signal, the DCP is correct as well.

You could also load the DCP into DCP-o-matic player and play with the playback audio matrix to check signals.

I can only assume that the cinema did something wrong. Maybe amps were not switched on, or the cinema processor was set to the wrong format.

Here is a test DCP that plays test signals through each audio channel. You can take it to the cinema along with your DCP and compare.


https://drive.google.com/file/d/1z-l2ag ... sp=sharing

[Gorkem Sifael]

Thanks Carl and Carsten,

Here is. link to the mxf audio file for your kind reference: https://wetransfer.com/

The order of the channels is correct, as far as I know.

They played another film in 5.1 at the theatre to show me that their system works well.

I will certainly bring along this sample file thanks. When I put it in premiere it shows 8 channels (the last 2 empty). I assume they are HI VI? Do you think I should make my DCP this way as well?

[carl]

Hi Gorkem,
That link seems to just go to the main page of wetransfer.com.

[Gorkem Sifael]

Sorry Carl, for some reason when I copy-paste the link it doesn't work. But now I manually typed it:

https://we.tl/t-U7vdFe5TB9

Thanks again for your kind support.

[Carsten]

The channel count of that test DCP being 8 is not relevant in a DCP. Some companies just put in additional empty tracks. You don't need to. Yes, when filled with audio, that would have to be HI/VI-N.

You could have 16 channels in a 5.1 DCP - 10 being silent - perfectly legal, and would work. I often see 14 channels in professional trailer DCPs - because, sometimes these trailers come as ATMOS and need 14 channels, and these companies do not bother using a different channel template for ordinary 5.1 or 7.1 versions.

Your DCP audio looks perfectly okay to me. The surrounds are subtle, but that is probably what is intended. I also listened through the channels, and, besides the already obvious visual waveform appearance, everything seems to be where it should be. Maybe you just expect more audible channel separation than there is? You can see that during the dialog (coming from the center speaker), there is very little signal from the other channels. But that's okay.

Which version of DCP-o-matic did you use to create that DCP?

[Gorkem Sifael]

Thanks Carsten.

I used version 2.16.29 on Mac.

If everything seems fine, I don't know what is the issue. Theatre could play another 5.1 film perfectly fine but not mine. There was no sound coming from any speakers outside of those that are at the top of the screen. If the DCP-o-matic output looks fine to you, the only step I follow after that is to use DCP Transfer to package it as ext. but I cannot imagine that being the cause.

Tomorrow I will bring the new DCP I made by panning stems myself, as well as the test DCP you gave me. I will also bring a copy of each in NFTS for any case that DCP Transfer is the cause. Thanks