DCP with 16 audiochannels?

[ErikSchuit]

Just upgraded to 2.16.55, created a DCP and the resulting DCP has 16 audiochannels.... 6 with the 5.1, 10 empty. A changed setting somewhere?

UPDATE: Downgraded to 2.16.50, all fine, 6 channels. Upgraded again to 2.16.55, 16 channels...

[carl]

It's a bit of a work in progress, but we're increasingly finding that DCPs without 16 channels present (even if many are silent) are failing the "QC" procedures of various major distribution companies.

[cintoli]

I was about to report on a separate post the same "mysterious" presence of 16 channels in the final DCP (when played in DCP-o-Matic 2 Player) when I had made sure it should have 6 tracks when I created the job in DCP-o-Matic 2.

The software version is the latest, 2.16.55.

Luckily, I have noticed someone else has already initiated a thread about it.

Because I will deliver the DCP to a client for theatrical distribution in Canada, should I have to worry about the presence of 16 channels rather than 6?

I can provide screenshots if necessary.

Thank you in advance for more information.

[carl]

I am not aware of any problems with having the full 16 channels rather than 6, and in fact if your DCP is subject to any checks by a distributor you may find it helps.

An alternative would be to revert back to DCP-o-matic 2.16.50. It dropped off the download server but I can restore it in a few hours.

[cintoli]

Thank you Carl!

I will give the 16-channel DCP a try with the client, who will definitely run QC (especially because they are paying for the material) and let me know if the DCP has passed it. I took a technical note of the feature.

[igit]

According to SMPTE-RDD-52:2020-Bv2.1 specification
If you are doing DCP in this format, then unused audio channels should be padded with soft sounds
For example, in new versions of EasyDCP, it is no longer possible to create audio of 6 channels - only 16.
I ran into the opposite problem - I needed to make a VF for a DCP created in the DOM apparently of an early version and it had 6 audio channels, I could not do it in EasyDCP because Creator can only create 16 audio channels if the DCP is created in the SMPTE standard- RDD-52:2020-Bv2.1

10.3.1 Channel Assignments
Channel assignment defines what audio signal is carried in each channel of the distributed track. Sound Track File channel assignment shall be indicated by a UL value in the Channel Assignment property of the Wave Audio Essence Descriptor.
The Static Container Channel Configurations in A.1 of SMPTE ST 429-2 shall be used, and the Byte 15 Value shall be set to “04h” (Channel Configuration 4) as noted in Table A.2 of SMPTE ST 429-2.
Channel Configuration 4 is noted as an “open” configuration without inherent constraints on the soundfield it carries. Therefore, the Sound Track File’s channels shall be mapped to channel numbers as listed in Table 3 below for use within a common soundfield group. Channels 9,10, and 16 shall be unused and shall be recorded with silence (all samples have a value of 0). Further, any unused channels in a soundfield group (as denoted by “-“ in the below table) shall be recorded with silence (all samples have a value of 0.

[IoannisSyrogiannis]

I am not aware of any problems with having the full 16 channels rather than 6, and in fact if your DCP is subject to any checks by a distributor you may find it helps.

An alternative would be to revert back to DCP-o-matic 2.16.50. It dropped off the download server but I can restore it in a few hours.

While compatibility is a nice feature and I am all for it, I would be grateful if I had the choice to have 16 audio channels -for its sake- or not, same as I currently have the choice to make HD aspect ratio DCPs or not. As an advanced setting.

I am experiencing long verification times and if I want to repackage, it's time consuming as well.
I wouldn't want to trade that with old software versions, though.