dcp omatic expectations

[PoaStell]

I have made a dcp from a feature length documentary that plays back in the app but I don't get any sound. I checked the files and the audio is there and plays OK in VLC. is sound playback in the app not a feature? or am I missing something obvious.

[carl]

There is no sound in the preview, so what you are seeing (or rather not hearing) is normal...

[PoaStell]

Ok thanks

[PoaStell]

All very helpful I made a feature length DCP that plays OK in DCPplayer.

However, due perhaps to my inexperience here, while the stereo and quality is OK, the sound level is quite a lot lower than the original mp4. If I make another DCP is there a way to lift the gain? is that, as I suppose, what 'gain' in the audio tab is for? Is there anything else I should do?

Now that all this seems to be up and running, a second question: The 44GB .mpg from which I'm building the DCP is very good but in AME there are a lot of choices. Is there a high end encoding that is more native to DCP? that would give better/quicker results via DCP-o-matic?

[Carsten]

How do you compare the audio levels of your source footage and your DCP? Usually, DCP-o-matic does not touch the audio levels, but wether you can leave it like that depends on the difference in level reference between your source content and the standard cinema listening levels. Admittedly, together with aspect ratio options, that is one of the hardest things to understand. Take your DCP to a cinema, play it there, make sure they are using their standard playback level. Don't trust software players on your PC. They can not establish a proper level reference.



The audio matrix allows you to distribute your sources audio channels into typical cinema audio channels. While standard stereo is not the best choice for cinema (at least not if it contains dialog), when you come from a stereo source, DCP-o-matic will usually assign both channels to Front Left and Front Right and that is a good start. You might as well mix L and R into C additionally (at reduced level), or use one of DCP-o-matics channel encoding options. However, make sure you can test your DCPs in a real cinema, because some options can have weird side effects.

- Carsten

[carl]

Now that all this seems to be up and running, a second question: The 44GB .mpg from which I'm building the DCP is very good but in AME there are a lot of choices. Is there a high end encoding that is more native to DCP? that would give better/quicker results via DCP-o-matic?

DCP-o-matic has to decode your input file and re-encode it into the DCP, so the better looking the encoding that you use, the better the DCP will look. The best encoding to use for input would be a lossless one (e.g. TIFFs for each frame) but obviously these take up a lot of space.

Nothing will significantly affect DCP-o-matic's speed; the time consuming part is the re-encoding to JPEG2000 for the DCP.

[PoaStell]

Both these responses are a great help. looking at the waveform I can see why the level is adrift a tiny handful of hammerblows peak at 00.db and have been missed in the time line work.

re the lossless original I tried 'animation' in AME but i couldn't, on this machine (quad core), find a way of playing the output thus not knowing if it was viable.

I'll try writing a test with TIF. Would it not make sense to write output from the timeline direct to jpeg2000? but not if dcop-o-matic was going to recode it.

All this is much appreciated we have been in a corner moving from being tv savvy to cinema.

[carl]

I'll try writing a test with TIF. Would it not make sense to write output from the timeline direct to jpeg2000? but not if dcop-o-matic was going to recode it.

Yes, if AME can write cinema-spec JPEG2000 (and do the XYZ colour conversion) then go for it. I don't know if it can or not: someone else may be able to say...

[PoaStell]

Hello Carl, I took our 115Gb DCP down to the Brentford Arts Centre this morning, the projectionist loaded into their Doremi system and hit play and it ran sound and picture perfectly. You may not be surprised but as a director/editor I have been well out of my competence with the TV to cinema transition. FWIW dcpplayer completed the loop very well, look out for the donation matching their charge.

[carl]

Hi there, I'm glad it worked and thank you for the donation.