Feature Film - Croping and sound sync

[Carsten]

That means that the dcp is problematic and will do the same at the cinema?

No, it is most certainly okay. Do you remember the datarate you chose for compression? You may look it up under the DCP tab after reopening the project.

The DCP-o-matic player uses a rather slow software decoder, per default, it is normal that there is some stuttering and droped frames when you play the DCP with audio.

What type of machine do you use? You would need a very fast multicore CPU to achieve full res decoding without dropped frames.


You may choose a lower decoding resolution to get a more fluid playback. Also, playback in dcp player is slowed down considerably if DCP-o-matic main application is running in the background, even when it is not actively encoding.

- Carsten

[Huiuuu]

Well i had my tries some months ago with other DCP software, and i had problem with bitrates more than 200mbs, so i think from now on i will use 100mbs datarate . I used 100mbs this time too. My pc wasnt good at running DCP . I have an i5 proccessor and my gpu is geforce 970 so i am sure its not enough processing power to decode. Dcp player does software or Gpu decoding?

So the LUFS are right? and usually when you mess with gain what value you put?

We will try the dcp at tuesday and i will come back with the results, I hope everything goes well..

[Carsten]

You can safely use slightly more than 200Mbit/s with DCP-o-matic. Just don't go above 230-240Mbit/s. DNxHD and Prores use similar compression technologies as DCP, so, it does make some sense to choose the dcp datarate in about the same ballpark as your source datarate, e.g. 150-200Mbit/s for a DNxHD 185 file.

Your LUFS value appears a bit low (too soft) in my experience, but it is hard to judge for a longer piece. You may ask the studio which reference level they chose. It may be they actually mixed to Dolby Level 7, so, had a rather high monitoring level, thus they may have steered it a bit too low for realistic cinema levels. That's a bit of a known issue between mixing studios and cinemas. It is certainly not grossly off, but after listening in a cinema, you may need to adjust it a bit. From the LUFS number alone, I would add a gain of +3 to +6 dB for all channels, but then again, without knowing the dramatic intention of the audio, this is hard to judge.


When you go to that cinema, make sure for the first test run that they use the same playback level that they typically use for features. That is typically a so called fader level number in the range between maybe 4 and 6.5
If they start pushing it up right away into everybodies comfort zone, you will not know where you are with this mix.


- Carsten

[cloud06]

I would not add gain, because your true peak is -0.4 dbFS so adding more than 0.4db would clip the signal.

If you feel that sound is too quiet at cinema - just add a note when sending DCP, something like “play at X dolby level”. This level is something you have to figure out when testing DCP in cinema.

Also, keep in mind that sound level feels different when cinema is empty and when it’s full. Sound designers usually go to first festival projection with audience and then refine dolby level suggestion. I usually have phone number from someone in projection booth, so if I notice sound is too loud or too quiet, I ask them to fix it. And this is then final dolby level to write down for all future projections...

[Carsten]

Sorry, I wasn't clear there with my statement 'from the LUFS number alone'. Of course, with the peak levels already near clipping, no way to add more gain, at least not without using external audio processing using compressors or limiters.

- Carsten

[Huiuuu]

Still no feedback from the cinema for the DCP i made .. I hope everything is fine.
Now they asked from a festival for a 24fps Subbed version so i am making a new one .. For subs i had to make a new master with encoded subs.. Is there any way through DCPomatic to encode subs in a no sub Master ? I mean without using the dcp feature for subs , but to print them on the image.
Plus , i am already half way through to finish the new subbed DCP , but i have to use the PC with another client. Does the pause feature work? And if i pause and save , can i resume the dcp making after a pc restart? (most likely not )

About the Lufs , the film is dialogue heavy comedy , without much of special effects, and i was colaborating with the sound mixer to give enough headroom for the "action scene" to be more of "BOOM" . So dialogues are max -9 db or maybe -6 on screams (mostly in the -12 - -18 db range) and the movie is 90% dialogues so i guess that makes the LUFS average smaller , and to look soft.
Maybe if we find the movie soft overall after the cinema screening, the best way is to mess with the theater dolby volumes like you said!

Thanks for everything!

[Carsten]

With DCP-o-matic, you can encode the subs into the image (burn in), or add them as timed text, so they are rendered by the server/projector at playout time. The timed text variant is mostly done as a VF, so you can deliver a (large) non-subbed OV version, plus a tiny subtitle VF. If space is not an issue, many people prefer to create a separate version with burnt-in subtitles, because that way, there is less risc that something goes wrong with the subs during playout. Timed Text subs are not 100% reliable.

Yes, in general, pause works, even across PC reboots. DCP-o-matic keeps tracks of what is already converted. I usually try to avoid doing multiple pause/restarts for safety reasons, but it is meant to cause no issues. No need to save after pause - the moment you hit 'Make DCP', the project is saved anyway, and all conversion results are saved on the fly, until you hit 'pause'.

I would love to hear your personal experience with the playback level. Again - tell them at first that they should initially try their normal feature/main show playback level, and listen to that at least for a few minutes. Make a note what fader level they used. I am nearly sure that you will find their normal level too low for your feature. So, since there is no easy way to increase the dcp loudness because of immanent clipping, you should include a letter with that DCP indicating the preferred playback level.

- Carsten