Audio not synced with video (looses sync)

Anything and everything to do with DCP-o-matic.
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Dusk
Posts: 10
Joined: Mon Feb 16, 2015 9:26 am

Audio not synced with video (looses sync)

Post by Dusk »

I have now created several DCPs and figured out, that the TRIM function (for example trim from 25 to 24p) will not snyc the audio. The first film was in 25p, audio included - after using the TRIM function from 25p to 24 the final DCP (also 24p) contained a not synced audio. :shock: My second film was in 23.96p - after trimming it to 24p, the same problem. Even if I seperated the audio to 24p manually, the audio was not synced. That means to me, this function does not work or has no benefit. To get a correct audio I always have to extract the film manually to 24p (with another software) OR only configure the DCP in preferences to 24p instead of 25p (meaning the dcps will run slower, as described by dcpomatic) Maybe this should be better described in the software.
carl
Site Admin
Posts: 2338
Joined: Thu Nov 14, 2013 2:53 pm

Re: Audio not synced with video (looses sync)

Post by carl »

Hi, which control in DCP-o-matic are you using to specify the new frame rate?

If you change "Video frame rate" in the "Timing" tab then you are telling DCP-o-matic that the frame rate it has detected for your content (source) file is wrong, and it should use the one you tell it. That will result in bad sync if you are, for example, setting a file which is actually 25fps to 24fps.

If you change "Frame Rate" in the "DCP" tab then you are telling DCP-o-matic that regardless of the source frame rate it should make a DCP of your specified rate, and fix the video and audio up so that it remains in sync at the new rate.
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