I have discovered that my RX6600 cannot use VDPAU to decode HEVC, although VA-API works OK. Unfortunately, VLC 3.x only supports VDPAU these days for hardware decoding.
I have raised this issue: https://gitlab.freedesktop.org/mesa/mesa/-/issues/10599 Mesa 23.3.5 just used to fail, but both Mesa 24.0.1 and 24.1.0-devel actually lock up the GPU and force me to reboot my PC. According to vdpauinfo: name level macbs width height ---------------------------------------------------- ... HEVC_MAIN 186 139264 8192 4352 HEVC_MAIN_10 186 139264 8192 4352 HEVC_MAIN_STILL --- not supported --- HEVC_MAIN_12 --- not supported --- HEVC_MAIN_444 --- not supported --- HEVC_MAIN_444_10 --- not supported --- HEVC_MAIN_444_12 --- not supported --- ... Cheers, Chris
