Im creating a DCP "work-in-progress" screener, it will be 2.0 stereo (5.1 will not be done in time)
Whats best best practices as far as compatibility is concerned?
Create a 5.1 DCP with LR and silence on the other channels? or create a 2.0 stereo DCP?
Only concerned about playback compatibility.
And yes, we know that stereo might sound bad without a center channel
I would suggest making a 5.1 DCP with silence on the other channels. DCP-o-matic will do that for you automatically (if you are using it).
I don't think there's any theoretical reason why a stereo DCP shouldn't work, but it's probably not worth the risk, especially as the extra file size is not really that significant compared to the overall size of the DCP.
In theory 2.0 DCP should work fine. Even EasyDCP has a 2.0 option. However, Im a bit sceptical
since there seems to be info pointing to certain playback systems will refuse the DCP because the
number of channels is below 5.1
I guess a 2.0 DCP could sound better if going through Dolby Pro Logic, but since it's a
rough and early screening, playback compatibility is the most important factor for us.
I think there were no actual playback systems with problems. I heard that some older TMS systems may have acted strangely on it. I wouldn't be concerned. Depending on your market, the SMPTE DCP penetration is high now, and all systems should have received software updates that have eradicated potential problems.
25fps is actually more a problem since there are still a bunch of servers around that can not play 25fps.
Dolby Pro Logic decoding is not activated in cinema sound systems by default. Some systems may have been configured to use it, but you have to ask for it specifically.
Maybe it is possible to place dialog on a separate center?
Carsten wrote: ↑Thu Feb 17, 2022 3:01 pm
25fps is actually more a problem since there are still a bunch of servers around that can not play 25fps.
Is that still really the case?
Since 2019 SMPTE has been the standard so if series 1 servers are still in use somewhere it must be really hard for that cinemas to run problem free since the world has accepted SMPTE now and even Cannes film festival now accepts 25fps DCPs.
My opinion is that now 2022 if a cinema is still using series 1 servers/projectors they just have outdated equipment and are no longer part of the game.
Update to the user who create this post:
To be on the safe side I would make 5.1 DCP and leave silent on the ch 3-6.
I don't thing stereo DCP should be a problem but just to be safe 5.1 is better.
Last edited by gunnar on Fri Feb 18, 2022 12:09 am, edited 1 time in total.
These are certainly mostly underfinanced operations. But I see a lot of operators still mentioning DSP100/DSS100 as their server. Not saying that they play a serious role in that business - but I would think that it is far safer to release a 2ch only DCP/MXF into the wild than a 25fps.Note the DSS100/DSP100 nonetheless had finally received a softwareupgrade that made it SMPTE compliant/compatible. Just not towards a wider framerate support.
Thanks for all your input. I think we'll go with a 5.1 (LR+silence) IOP just to be sure there ain't any playback issues. But another thing popped into my mind, how would you name the DCP, as 20 or 51?
It's actually not important. There had been a range of discussions wether the naming should express the technical number of channels, or the actual channel utilisation. Most people go with the technical channel number. As a side note - while a 5.1 channel DCP actually contains 5+1 channels on channels 1-6, a 7.1 DCP always contains 12 channels, as Back Surrounds have to go to channels 11 and 12. So, a 7.1 audio MXF is NOT an 8-channel MXF, but a 12ch MXF. Also, a 5.1 DCP may contain e.g. HI-/VI-N channels on 7 and 8 (but that should be indicated in the naming as well).
My personal choice - as I never experienced or heard about issues with 'real' stereo-only DCPs is, to actually use only channels 1+2 and also name it 20.
So that staff or whoever deals with the DCP also knows that there is really no center, LFE, or surrounds. Because, it could happen that in 'prototype'/screening DCPs, signals get routed to the wrong channels. So, I would prefer to see a clear indication about what actually is in the DCP.
Also, 2ch, 4ch, 5.1 DCPs are perfectly within spec.
Keep in mind - at least on a playback server, the naming is only there to give hints to a human projectionist. On some Theater Management Systems, software MAY read out certain DCP aspects and perform some settings 'semiautomatically' according to some of that information. That, however, is explicitly NOT recommended by ISDCF and industry people, as the naming was never meant to be evaluated database-style.
