"New Plex" on Windows has issues with hardware decoding 10bit HEVC

Thanks for reopening this, hope you guys are eventually able to overcome it…

I’ve had some fun playing around with this one, it 100% seems to be tied in with using the AMD GPU to Hardware decode (I’m on a 5700XT, so Navi architecture). Other players - speficially VLC & PotPlayer - don’t produce the same artifacts with HW Decoding enabled.

I tried re-encoding various video files I have as H265 10bit, and interestingly, when the source video was 8bit, the 10bit H265 often - but not always - played back okay in Plex. However, if I encoded a 10bit H265 as 8bit H264 (or H265), and then reencoded it as 10bit H265, the artifacts would disappear in the 8bit files, then reappear in the 10bit. Collectively, that doesn’t add up to me, but I don’t do video compression for a living either ;o).

Something else I’ve realised, is that the Navi VCE currently sucks (this isn’t limited to Plex), so using hardware encoding on an Navi GPU in general is probably just a bad idea right now. YMMV.

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