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Audio does not follow Speed Change and gets out of sync

PostPosted: Mon Feb 18, 2019 4:04 pm
by DanielMahlknecht
Hi,

currently I have a problem in DaVinci 15, that when changing frame rate in a selected clip, this will only affect Video, but not audio resulting in out of sync sound.
This seems to be a Bug in the system.
I change the frameate of my material in the media section of DaVinci in the Clip Attributes.

I often need to change imported 8mm footage from 25f/sec to 16f/sec.
I didn't realize this problem immediately as most of the 8mm footage I get is without sound.
I still can do this with Adobe Premiere but I wanted to abbandon Adobe products and use only DaVinci...

Re: Audio does not follow Speed Change and gets out of sync

PostPosted: Tue Feb 19, 2019 5:16 pm
by DanielMahlknecht
here is a screenshot that shows what happens. It shows two times the same clip, one with the native framerate and one with the framerate set to 16f/sec. The clip and the audio track stretch to the new duration, but de facto the sound does not change as you can see on the waveform of the audiotrack.

Re: Audio does not follow Speed Change and gets out of sync

PostPosted: Tue Feb 19, 2019 8:41 pm
by Glenn Sakatch
That's not a bug...that is the way it works...in many programs. If you want to stretch or shorten the audio you would need to do a separate process.

Re: Audio does not follow Speed Change and gets out of sync

PostPosted: Wed Feb 20, 2019 10:14 am
by Andrew Kolakowski
Unlink it from video and then use speed change option under right click on waveform. You can use fps as units, so it's easier.
Some NLEs adjust audio when you do fps change (so it's easier for the user). It just may be "dangerous" as some tools do poor audio processing (specially pitch correction).

Re: Audio does not follow Speed Change and gets out of sync

PostPosted: Wed Feb 20, 2019 1:20 pm
by Daz Wood
Andrew Kolakowski wrote:Unlink it from video and then use speed change option under right click on waveform. You can use fps as units, so it's easier.
Some NLEs adjust audio when you do fps change (so it's easier for the user). It just may be "dangerous" as some tools do poor audio processing (specially pitch correction).


I'm not too impressed with the time-stretch quality in Resolve, changing the time of the clip but keeping the pitch unchanged.

Re: Audio does not follow Speed Change and gets out of sync

PostPosted: Wed Feb 20, 2019 1:48 pm
by Andrew Kolakowski
So you mean pitch correction is not very good. In some cases not doing pitch correction at all is better.
Not many tools have it very good. It's difficult subject same as fps conversion.

Re: Audio does not follow Speed Change and gets out of sync

PostPosted: Wed Feb 20, 2019 2:06 pm
by DanielMahlknecht
Hm, it works perfectly in Premier and at its tim it did also in FinalCut 7, so this is new to me...
If this is really supposed to work this way in DaVinci, it would be nice to get something like an audio follows video option one could select.
In my case Pitch correction is not necessary, or would even be harmful as i capture 16f/sec footage at 25f/sec and therefore get a to high pitch which would be corrected automatically when setting everything back to 16f/sec...