audio out of sync

Anything and everything to do with DCP-o-matic.
jillmobley
Posts: 23
Joined: Thu May 01, 2014 8:44 pm

audio out of sync

Post by jillmobley »

I have a video that was taken from VHS and converted to MP4. The MP4 plays fine. I watched the DCP in the DCP-o-matic player and the sound is way out of sync. I will try it at the theater this evening.

Is there some setting in DCP-o-matic I need to change?

Any suggestions will be very much appreciated.

I have a large audience for this on Friday night. YIKES!
carl
Site Admin
Posts: 2362
Joined: Thu Nov 14, 2013 2:53 pm

Re: audio out of sync

Post by carl »

Hi Jill

One idea would be to try the test version of DCP-o-matic to see if things are better there. It has a fix for a general class of audio sync problems.

Alternatively, can you make the MP4 available somewhere so I can check it out? carl@dcpomatic.com if so.

Best,
Carl
carl
Site Admin
Posts: 2362
Joined: Thu Nov 14, 2013 2:53 pm

Re: audio out of sync

Post by carl »

Thanks for the video. From some tests I think if you use 2.17.x and set the "delay" in the audio tab to about 370ms it should be pretty close.
jillmobley
Posts: 23
Joined: Thu May 01, 2014 8:44 pm

Re: audio out of sync

Post by jillmobley »

I will try those settings, but I was unable to install the test.

Error opening file for writing:
C\Program Files\DCP-o-matic 2\bin\libintl-8.dll
carl
Site Admin
Posts: 2362
Joined: Thu Nov 14, 2013 2:53 pm

Re: audio out of sync

Post by carl »

Can you make sure you have closed any other parts of DCP-o-matic first? Or does a reboot help?
RAY-NUE
Posts: 92
Joined: Mon Aug 21, 2023 4:18 am
Location: Ratchaburi, Thailand

Re: audio out of sync

Post by RAY-NUE »

jillmobley wrote: Mon Oct 30, 2023 10:26 pm I have a video that was taken from VHS and converted to MP4. The MP4 plays fine. I watched the DCP in the DCP-o-matic player and the sound is way out of sync. I will try it at the theater this evening.

Is there some setting in DCP-o-matic I need to change?

Any suggestions will be very much appreciated.

I have a large audience for this on Friday night. YIKES!
The MP4 must change to a 24 fps frame rate in the Davinci timeline, or it doesn't. Use the original settings from VHS, such as 25 or 30 fps, and the sound must be synced. Then render the MP4 as Jpeg2000, then render the audio as wav 2.0 separately, and import it into the DOM.

****Timeline frame rate Must be the same frame rate as j2c and DOM.***
jillmobley
Posts: 23
Joined: Thu May 01, 2014 8:44 pm

Re: audio out of sync

Post by jillmobley »

I followed Carl's suggestions and I have an acceptable DCP. Thank you!

I do not have access to the original VHS tapes, so I cannot change the way it was converted to MP4. (unless RAY-NUE you are meaning I change the MP4?)
Carsten
Posts: 2665
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: audio out of sync

Post by Carsten »

@carl - what was the issue? Is there an actual sync offset baked into the MP4? Or some other weird codec related issue?
carl
Site Admin
Posts: 2362
Joined: Thu Nov 14, 2013 2:53 pm

Re: audio out of sync

Post by carl »

It looks like the fixes in 2.17.x are needed to make the sync consistent. But even playing the original in VLC for me the sync was quite a way off - 370ms made it look OK to me with a quick test.
RAY-NUE
Posts: 92
Joined: Mon Aug 21, 2023 4:18 am
Location: Ratchaburi, Thailand

Re: audio out of sync

Post by RAY-NUE »

jillmobley wrote: Thu Nov 02, 2023 1:17 pm I followed Carl's suggestions and I have an acceptable DCP. Thank you!

I do not have access to the original VHS tapes, so I cannot change the way it was converted to MP4. (unless RAY-NUE you are meaning I change the MP4?)

What system is VHS? PAL 25fps or NTSC 30fps?