clip audio repeatedly doesn't correspond to video, at random, every time I open the program

[samuelh65354682]

Really at my wits end with this program.

I'm working on a web series/doc and my three primary sequences are about 1.5 hours each.

I shot on a cheapo Panasonic camera many years ago and it's all in that MTS stream format.

-For some reason I can't comprehend, every single time I open the program, the audio and video for at least a quarter of the clips is suddenly different, does not match. To clairfy, the clips where the audio changes are all from the same media file; in other words, if I have two MTS media files on my harddrive, 0004.MTS and 0005.MTS, all of the clips associated with, say, 0005.MTS in Premiere will have changed audio, (not just some of the clips), while all clips from 0004.MTS will be normal. The only pattern I can detect is that the clip's audio is usually mixed with a clip with the same name, but from a different card dump from a different day.

-Premiere always starts conforming the audio when I open the program - every time.

-This last time probably 50-100 clips do not have corresponding audio, and it's usually different clips, every single time I open the program.

-If I reveal the clip in finder, and preview it, the audio is correct.  If I import it into premiere, it's wrong.

-The only fix is to copy the clip in the finder folder, rename it and then import it into Premiere - then the audio will match correctly.

-Then I get to start my daily overcutting of 50 to 100 clips. Thanks Premiere.

-Then when I quit the program and open it again, I get to do it all over again. Except it's different clips. 

-I'm sure it's probably the needless and constant audio conforming that it seems compelled to do everytime it's opened (and do wrong, of course).

I'm working on a 2018 macbook pro 2.9 6 core i9, radeon pro vega20 4 gb, premiere 22.4.0, footage is on an external SSD

[RobShultz]

Your videos were probably shot in a variable frame rate which may cause audio to randomly go out of sync. I recommend using the free app HandBrake to convert your videos into a fixed or constant frame rate and then bring the converted videos back into Premiere.

[Warren Heaton]

Since you're on macOS, use Shutter Encoder (donation-ware) to transcode the MTS files to ProRes 422 LT.  Set your Sequence Video Previews to Custom QuickTime ProRes 422 LT as well and you're editing should hold sync without messages about conforming.

If the MTS files are still in the original AVCHD directory structure, drag and drop the AVCHD package to the "Chose files" area.  If the MTS files are separated from the AVCHD directory structure, drag and drop the MPS files.

In the "Choose function" pop-up menu, locate "Editing codecs" and choose Apple ProRes and set the corresponding pop-up menu to "LT".

With AVCHD, I like to use the "Change" option to export the resulting ProRes clips to a different location than the AVCHD/BDMV/STREAM/ location.

Then click "Start function".

1080 ProRes 422 LT requires about 700MB per minute.

To quickly create a ProRes 422 LT Sequence in Premiere Pro, drag and drop one of the resulting "_Apple_ProRes_LT.mov" files into an empty Timeline panel or New Item icon at the bottom of the Project tab.

Exporting a finished edit at ProRes 422 LT will be really fast.  If you're exporting rough cuts for review outside of Premiere Pro, use ProRes 422 Proxy (that will also be fast).  If delivering H264/H265, export to that once you've locked picture and are ready to publish a delivery file via Premier Pro or Media Encoder.

Other options:

• Right-click the MTS files (drill down to the STREAM folder if needed) and choose Encode Selected Video Files.  When the Encode Media dialog box appears, set the Setting pop-up to Apple ProRes for Apple ProRes 422 video and Linear PCM audio.  Pros:  No other software needed, just use macOS.  Cons:  There's no status bar to keep track of the progress and ProRes 422 is the only option (ProRes 422 LT will save about 300MB per minute).
• Open the AVCHD directory in QuickTime Player and then use File > Save... for H264 MOV files or File > Export... for HEVC or H264 MOV files.  Pros:  Easy.  Cons:  No batch processing and while H264/HEVC is great for playback in a media player app, they're not great for editing.
• If Final Cut Pro is installed, import the AVCHD package or individual MTS files into a Library with create High Quality Media enabled and then copy the files out of the restulting High Quality Media folder out of the FCP Library package.  Pros:  Easy and the process can be monitored in the Background Tasks window.  Cons:  Resulting clips are ProRes 422 when ProRes 422 LT is fine and would save about 300MB per minute. 

[Kevin-Monahan]

Hi Samuel,

I've seen this in several other cases since 23.0. Yours is a Panasonic camera, so you do have a constant frame rate. I think it's your audio.

There may be a bug with AVCHD footage in the audio is supposed to be handled by the OS, I think it's AAC. So, it's either that Windows no longer than deliver that support or there is a bug on Premiere Pro for not detecting that audio.

A workaround is to rewrap the audio to another codec using an FFMPEG tool, like Shutter Encoder. I'll upvote and will continue to advocate for this fix. I am not on the product team, but I'll raise the issue to get their attention too.

Thanks,
Kevin