Vf metadata different from OV

Anything and everything to do with DCP-o-matic.
macg
Posts: 7
Joined: Wed Apr 02, 2025 8:18 pm

Vf metadata different from OV

Post by macg »

Hi everyone,
I'm trying to create a VF for the first time.
The OV has 16 channels but only 6 are being really used by the 5.1 mix. The cpl reflects that.
When I import the OV and set the VF to use the audio it seems the program "thinks" that the OV is 7.1 with all the channels being used, so the name changes to _71 instead of _51 and the cpl shows 7.1 with HI, VI, Dbox, etc.
Do you think this can be a problem? When they try to play the VF, will some error show up, or have any unwanted behavior?
Is there anything I can do to make the metadata for the VF reflect the actual audio channels being used?

Thank you!
Carsten
Posts: 3127
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: Vf metadata different from OV

Post by Carsten »

That happens probably because DCP-o-matic per default assigns all OV channels in the matrix (because it doesn't know which of the 16 channels are unused). I guess this will not happen when you deselect all unused channels in the matrix (untick all green connection squares for those channels).
macg
Posts: 7
Joined: Wed Apr 02, 2025 8:18 pm

Re: Vf metadata different from OV

Post by macg »

Thank you Carsten.
The thing is I'm not being able to deselect any of the green boxes, it's just fixed and I can't change anything.
Is that the intended behavior?
Do you think it makes sense to use the metadata editing app (I forgot the exact name) to edit the cpl metadata for the audio channels of the VF?
I'll try again to change the channel assignment, but which do you think is a better bet if I can't: changing the metadata or just leaving it as 71 hi,vi,dbox etc (or something else I didn't think of)?

Thank you
Carsten
Posts: 3127
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: Vf metadata different from OV

Post by Carsten »

I don't think that editing the metadata is a good idea. If I understood you right, you reference OV audio, so, in that case, it is true, you can not deselect audio channels in the matrix. I guess I need to set up a project like this in order to see what happens. Of course, you could edit the CPL name manually to reflect the actual acive channel config, but that is not a good idea if SMPTE metadata still conveys a different soundfield.

Hmm, I understand DCP-o-matic routinely suggests to configure 8 or 16 channel audio to cater for external service workflows - but I myself usually restict myself to the channel count that I actually need. But even that doesn't help in every situation.

There may be a feature missing in dcp-o-matic...
barber
Posts: 73
Joined: Fri Apr 15, 2016 4:03 pm

Re: Vf metadata different from OV

Post by barber »

Hi,

I see that too. The MainSoundConfiguration metadata of a Version File should reflect the mapping of its OV, but it doesn't.
For example, if the OV is a DCP with 8 channels created from a stereo file, the CPL correctly shows

Code: Select all

<meta:MainSoundConfiguration>51/L,R,-,-,-,-,-,-</meta:MainSoundConfiguration>
But a VF that refers to its audio assets will have a CPL containing

Code: Select all

<meta:MainSoundConfiguration>51/L,R,C,LFE,Ls,Rs,HI,VIN</meta:MainSoundConfiguration>
and DoM will suggest a naming including "51-HI-VI"

This is a recent bug, less than one year. Only the MainSoundConfiguration metadata is affected, MCASubDescriptors are OK.

As a workaround you can manually uncheck the unused channels before checking "Refer to" in the Version File setup window.