I am experiencing artefacts and noise when playing back a range of different HEVC 4K videos. I've been unable to identify what makes one video faulty, while another one is fine.
This only occurs on LibreELEC 9.2.1. When running on LibreELEC 9.2.0 it's fine.
I'm using the Plex addon. The client (RPi4 on LE) is configured to 'direct play' and is marked as 'HEVC' and '4K' capable. The Plex server confirms it's direct playing to the client when I playback.
Sample 10sec clip that exhibits the problem (link should remain valid until May 28th): sample
Some pictures of the issue (taken while playing the sample clip from above) can also be seen at: Imgur: The magic of the Internet
Hope this helps to narrow down what's going on, and thanks for all your works.
EDIT: Resolution has been found! Huge thanks to HiassofT and the RPi devs.
Good news, RPi devs found the issue and fixed it in the latest firmware. I've just confirmed that the sample plays without artefacts with it.
Please switch to LE 9.2.1 again and run these commands to update to the latest firmware:
After rebooting the firmware version should be May 22 2020:
Please also check with your other problematic files that showed artefacts if they are fine, too.