Problems with hardware acceleration when using .MTS

I am happy to share my projects and files with you if that helps! Message me in private and we go from there.

Thanks for the additional info and for trying that out @Bernhard Walzl! Can you see the performance issues in a brand new project with a single file or do you have to create a more complex sequence to see the problem?

Would you be interested in sharing any sample files with the team so we can take a look? I can message you if so. 

I just downgraded to Premiere Pro 25.0 and this is working !

Hi!

I am on the latest macOS (26.0.1 (25A362)) and Premiere (25.5).

Media Files Properties on the MTS file takes very, very long to load. About 3 minutes. This is not the case with other files, only .MTS.

File Path: /Volumes/123/456/private/AVCHD/BDMV/STREAM/00000.MTS
Type: MPEG Movie 
File Size: 1,98 GB
Image Size: 1920 x 1080
Frame Rate: 59,94
Source Audio Format: 48000 Hz - Compressed - Stereo
Project Audio Format: 48000 Hz - 32 bit floating point - Stereo
Total Duration: 02;45;57;56
Pixel Aspect Ratio: 1,0
Alpha: None
Color Space: Rec. 709
Color Space Override: Off
Input LUT: None
Video Codec Type: AVCHD H.264 4:2:0 

This is happening with other projects using MTS files. They are stored on an external hard drive. I also tried to work on a local drive.

I generally don’t use any third-party plugins. I did, however, install the Insta360 plugin recently, not sure if this has a connection. I don’t remember which version was working properly, as I keep Mac and Adobe on auto-update.