audio out of sync

[jillmobley]

I am sorry, I did not have access to the original VHS. They were several clips recorded from defferent tv shows then put together in the late 80's/early 90's. In the last year or so a friend converted all her VHS tapes to mp4. I was given on of these conversions.

I used Carl's suggestions and got a pretty decent dcp. I had a private event at my theater and everyone was delighted to see the old footage.

I always appreciate everone's help here!

Jill Mobley
Kennett Palace Theater

[Carsten]

While mp4 is pretty much a standard file format, it may be that tape captures use special features of the h.264 codec that may introduce timing issues. Tape captures, depending on the capture hardware, may show timing jitter, and that could cause these sync issues you noticed.

[RAY-NUE]

I am sorry, I did not have access to the original VHS. They were several clips recorded from defferent tv shows then put together in the late 80's/early 90's. In the last year or so a friend converted all her VHS tapes to mp4. I was given on of these conversions.

I used Carl's suggestions and got a pretty decent dcp. I had a private event at my theater and everyone was delighted to see the old footage.

I always appreciate everone's help here!

Jill Mobley
Kennett Palace Theater

I recommend importing these mp4s into davinci resolve and checking the frame rate in the metadata. Then set the timeline to match the frame rate (24/25/30 fps) and place these mp4s in the timeline. Then move the sound to sync with the lips in the picture. Then render the image as jpeg2000 Kakadu DCP and then render the wav audio, separate the tracks for the final 5.1-7.1 mix (Vegas Pro/ Logic Pro / Pro Tools / Steinberg /Audition) . *** The davinci timeline framerate and DOM framerate must be the same. ***

[minoux]

Carl et all hello

Could you help me figure out a consistent audio sync issue on a project being authored in 2.18.11?

My project originates in Davinci Resolve. 25fps timeline. Some source media varies in framerate, and those have been adjusted to conform to 25 (aka video sped up or slowed down to match the audio). Everything is in perfect synch in Resolve.

The project has been exported as ProRes 422 HQ.

The ProRes file has been checked using QuickTime and VLC projected in a cinema and viewed on the desktop and shows no signs of being out of sync.

During the test screening of the DCP in the cinema, the version authored in dcp-o-matic is visibly out of sync (by some frames). A DCP authored in EasyDCP using the same ProRes file is still marginally out (of sync but by fewer frames) but not perfectly in sync. Doesn't appear to be a 'drifting' problem associated with the cinema projection because we stopped and started, and the sync problem was consistent.

Is there metadata retained in the ProRes file that each of these software applications 'interpret' differently and that could account for our mystery synch problem? I was under the impression that once a ProRes file has been generated, the audio is 'baked' in the file and should theoretically stay as is, right?

Could you advise on the ideal workflow in this situation to avoid the guesswork of adjusting the audio ms delay during authoring? I should add that the audio drift is not visible when viewing the DCP in the DCP-o-matic player. And the verifier, too, throws up no 'faults' with the ProRes Framerate. I set the authoring framerate to 25 (as is the ProRes file) and have not made any adjustments to the 'Timing' tab in dcp-o-matic.

Ta!