P: .MTS video and audio not synched on Mac OS and Adobe 24

[Patricia227709208kyp]

I am using a MAC Studio M2 machine for video editing.  Once I updated my OS to Sonoma 14.6.1 and Adobe Premiere to 24.6.1, I began having issues with importing video files.  When I import a .MTS (AVCHD) video in Premiere Pro, there is an audio drift of approximately 20 seconds.  

I did not have any issues when the OS was Ventura 13.6 or an older version of Sonoma and Abobe Premiere was 24.2.1. 

I am not sure what the issue is at this point.  

[defaultovzfzx2t0v0k]

Hi,

I'm currently working on a project that has been shot in AVCHD. I imported all the files using the media browser, and while most of them are fine, the spanned files get ouf of sync every time they enter a new section (they are 2G files).

Any idea on how to resolve this ? I'm running the latest stable version of Premiere Pro on a M1 Pro MacBook Pro.

Many thanks

[kai_2482]

For several weeks now, my MTS files have been loading out of sync. The audio is ahead of the video (about 1 sec), and at the end, silence is added for as long as it takes for the video to finish.

The files used to work properly, but now they are suddenly no longer lip-synced.

What has changed? What can I do to fix this?

Thank you for your help!

[Ann Bens]

This might help

Troubleshooting linking and importing errors with MTS and MP4 files after updating to Premiere Pro C...

If not:

How do I write a bug report? - Adobe Support Community

[Theo Kooijmans]

If you install the latest Win11 version you don't have windows support voor ac3 audio anymore.

If you try to import Sony MTS clips with ac3 audio you get only video.

You can fix that by installing the dolby ac3 app from microsoft store.

Now these clips import fine in CC2023.3 and lower and ar perfect in sync.

With cc2023.6 and higher this import goes badly wrong however, audio is most of the time 13 frames off.

Steps to repro

With this link you can download the ac3 pluggin and a reference clip (MTS)

https://tkooijmans.stackstorage.com/s/SbNhQujTtewNiKcX

In CC2025 you see this, audio stops early

In CC2023.3 or lower it's perfect in sync!

[kai_2482]

Thank you kindly.

[MiriamVT]

Hi,

I have recently encountered an issue when updated to 25.0, when I preview some of the footage, the audio is delayed for about a second. Only clips at random are like this, the others are synced as normal. When dragged to the timeline, the audio delay is there and there a cut off about a second before the footage ends. Is this a bug from the new update? Tried looking online and haven't had much luck. This has never happened before and its quite frustrating having to sync up the audio on the specific clip I need to use, whereas the footage/audio on my camera is perfectly fine. Anyone that can help I would appreciate it. Thank you!!!!!!!!

(I'm on Windows 10 and using Premiere Pro 25.0)

[R Neil Haugen]

What is the media involved? And what is different between the clips with audio synced correctly, and those that aren't?

[jamieclarke]

Hi @MiriamVT -  We need a few more details to try to help with the issue. 

Thank you @R Neil Haugen for jumping in.  

Please let us know your answer from Neil.

We also have an open bug related to sync issues with MTS files, or AVCHD.

Sorry for the frustration.

[MiriamVT]

Hi @R Neil Haugen ,

The media involved is video clips from my Panasonic camera (HMC 150), and there's no difference between the clips, other than the audio being a second delayed. I checked on my camera and all of the footage is played normally

[MiriamVT]

Hi @jamieclarke !

I answered R Neil and my answer was:

The media involved is video clips from my Panasonic camera (HMC 150), and there's no difference between the clips, other than the audio being a second delayed. I checked on my camera and all of the footage is played normally

Any more details you need? I can provide a screen record if that helps. Thank you for the reply!

[R Neil Haugen]

It would be interesting if you checked the files in MediaInfo, a freebie utility app you can download and install easily. It's heavily used "here" to check file data.

Drag/drop a file onto the MediaInfo icon on your desktop, when it opens choose Tree View, and get a screengrab of the audio data section. Do this with a file that plays properly, and one that has the delay.

Let's see if we can see some difference in the audio metadata.

[JammyPhantom]

Hi, almost all of my cameras use .mts files and Premiere has never had an issue with them until the 2025 version. Now every file I import, the sound is offset at the end with around 30 frames of silence, so everything is out of synch and has to be manually dragged back which is mighty frustrating. I just updated my premiere this morning to see if the next version up fixes it ( v25.1.0 Build 73 ) but no joy. Has anyone else hit this annoying problem?

Premiere 25.1.0 Build 73
Windows 10 v22h2
Intel Core i7
32Gb

[filmspezialist]

I encountered this problem in PP 24.6.3 already and filed a bug report. As far as I know Adobe staff has agreed that this is a bug. Hopefully this will be fixed soon.

By the way: in my case it is not 30 frames but just 18 frames out of sync

[wxthings]

Yes, same bug for me on version 25.1 so I had to go back to version 23.6.8 for things to work correctly.