Adobe Premiere CC 2020 Audio Out of Sync After Export

[#1]

I have a project timeline where audio has been synced, but when I export to h.264 or other codecs, it goes in and out of sync at random areas. It doesn't just go out of sync, it comes back in sync again. But in the timeline it is all in sync. What could cause this and how to fix?

[#2]

I have a project timeline where audio has been synced, but when I export to h.264 or other codecs, it goes in and out of sync at random areas. It doesn't just go out of sync, it comes back in sync again. But in the timeline it is all in sync. What could cause this and how to fix?

[#3]

Same problem. Just updated OS to Catalina, and updated Premiere and Media Encoder to CC 2020. Audio completely out of sync in exported video file. Timeline is in sync.

Please send help...

[#4]

I am so fustrated!!!  I have tried everything I can think of and still having the same problem.  Has anyone found a fix yet?????

[#5]

Same problem here as well.  All is synced until I export to h.264

[#6]

Marjiea,

Which camera shot the footage? If you acquired the footage with a mobile device, drone, or screen capture software instead of a camera, kindly optimize your footage by transcoding it prior to editing with it. I recommend ProRes LT.

After that your editing experience and exports have few problems.

Trying to maintain the integrity of a video file from start to finish with H.264 or HEVC files that have a frame rate that is fractional and/or variable instead of 24 fps, or 30 fps or 60 fps is a lot to ask.

One good rule of thumb to follow is:
Optimizing your video files before you begin editing with them, always offers a better result on export. I would ask you to try a test with your current workflow and see if you get a better result.

Thanks,
Kevin

[#7]

Thanks for your reply, Kevin!

The footage was recorded using Zoom and a quality headset and microphone on a desktop computer.  The footage plays nicely on the timeline (video and audio are synced), but gets just slightly out-of-sync (just enough to notice) after export.  Could our setup still be the cause?  (didn't use mobile, drone, etc.)

I appreciate your help!  I will try your suggestion to see if it makes a difference.  

[#8]

yeah, that's the problem.  use handbrake to convert to constant frame rate...

use mediainfo to determine whether your source is variable or constant frame rate

https://mediaarea.net/en/MediaInfo/Download

if it's variable use handbrake to convert to constant frame rate

https://handbrake.fr
and here's a tutorial on how to use handbrake

https://www.youtube.com/watch?time_continue=34&v=xlvxgVREX-Y

[#9]

I did already check the original/source video with mediainfo and it was constant framerate.  That's why I'm finding this so confusing.

Thanks again for any feedback ... it sure is appreciated!