Audio plays out of sync - even in source viewer

[tom_6243]

We're running Premiere Pro on 75 fairly new PCs and storing/ accessing/ playing media off a shared college network drive. I don't have the spec to hand (but can retrieve after the weekend if nec.)

Some students' projects play clips with audio out of sync by 20-40 frames (video late). The source clips are h264 .MTS files.

I would appreciate some tips for a workaround. E.g. short term: transcoding (to what?)/ moving to local drives (eg PC HD)/ changing network settings. Or long term: invest in department-only RAID.

Is anyone else having this? Apologies for vagueness. I can fill in exact specs if required.

[Peru Bob]

Moving to a local, fast drive would be the best option.

[tom_6243]

I moved the assets to the desktop. Still out of sync (video 17 frames late.)

it's premiere pro 2023 

is there a setting I can check?

[MyNameIsOriginal_Jay]

I don't know if this will help or not. I just learned that Premiere Pro doesn't like MTS files anymore. They import with audio and video unsynched. I just recorded an MP4 file and it worked great. Now I have to re-record everythnig I did earlier. Blah!

[tom_6243]

Thanks, I'll try transcoding the MTS files to something else. Surely you can transcode yours too rather than re-shooting?

[MyNameIsOriginal_Jay]

I'm having the same issue and the files are on a fast drive. That isn't the issue.

[MyNameIsOriginal_Jay]

I'm on 2025 Premiere Pro

[RobShultz]

Did you record off of web or phone? There's a good chance that it's a variable frame rate. You may want to try using the free app handbrake to convert your raw footage to a fixed frame rate.

[tom_6243]

Recorded on a Panasonic AC-90 camera so not amateur nor VFR.

I'll try next transcoding the MTS files to something more useable, like ProRes. 

Thank you, all. I'll report back.

[tom_6243]

Transcoding to ProRes doesn't work. Moving to Desktop doesn't work.

workaround: unlink video and audio, move audio later, re-link audio and video. 

it's maddening

[Averdahl]

Are the audio in the files Dolby Digital?

There are more people that has the same issue as you with mts-files with Dolby Digital audio. I have it as well with mp4-files with Dolby Digital audio.

Try to download Premiere Pro 23.6.8 and test the files there. This version of Premiere Pro does not have this out-of-sync-issue so thats the best workaround now. 

More here:

https://community.adobe.com/t5/premiere-pro-discussions/no-ac3-codec-in-windows-11-24h2-solution-is-...

I would appreciate some tips for a workaround. E.g. short term: transcoding (to what?)/ moving to local drives (eg PC HD)/ changing network settings. Or long term: invest in department-only RAID.

Is anyone else having this? Apologies for vagueness. I can fill in exact specs if required.

By @tom_6243

[tom_6243]

Thanks. 
the files DO have Dolby Digital audio.

my Mac runs premiere 23.6.9 (and plays ok)

the students' PCs run premiere 24.6.3 (and SOME play in sync and SOME do not). 

the issue is intermittent ie some projects are ok and some not, and some students working on a certain PC are ok yet when they move to another PC in another room it's suddenly not ok. 

is the solution to move BACK to premiere 23.6.8 ?

[Averdahl]

For me the solution is to go back to Pr 23.6.8. I remember having the same issues in Pr 24, intermittent there as well. In Pr 25 it seems to be always out of sync.

[tom_6243 · Accepted solution]

I wanted to update this thread for anyone else having sync issues with assets that contain Dolby Digital audio (in my case, .MTS files from Panasonic AC-90 cameras).

Transcoding to DNxHD 1080p/ 25 or Apple ProRes files, using Adobe Media Encoder sometimes fixes the issue. The fact it doesn't always work may be to do with Premiere Pro sometimes linking to incorrect media despite being manually instructed to re-link to transcoded assets? I use a question mark here as it's unclear to me why this method only works sometimes.

Rolling back to a previous version of Premiere Pro isn't an option because we are an establishment that relies on having something called CyberEssentials Plus certification which specifies we must be using latest updated versions of our software. So that's not possible.

The intermittent nature of this problem has berm especially frustrating, as we're keen to find a solid problem solving solution we can instruct our students to use from now on. Quite understandably students are bereft that their work is being compromised by out-of-sync audio, and that we cannot provide a reliable solution.

[Averdahl]

The reliable solution in that case is not to use Adobe products to transcode unless you are using Adobe Media Encoder 2023 to transcode the files. 

You can also use Shutter Encoder - Encoder | Converter video FREE PC | Mac to transcode the files. It´s free and will solve the issue to 100%.

Transcoding to DNxHD 1080p/ 25 or Apple ProRes files, using Adobe Media Encoder sometimes fixes the issue.

By @tom_6243