Just tried this on the Station P1 with kernel 6.6.7 (including https://github.com/armbian/build/pull/6051) and Bookworm. x264 works but hevc does not. Tried a random movie encoded in x265
[ffmpeg/video] hevc: v4l2_request_probe_video_device: select capture format failed
[ffmpeg/video] hevc: Failed setup for format drm_prime: hwaccel initialisation returned error.
ffprobe of the same file says
Stream #0:0: Video hevc (Main 10), yuv420p10le(tv, bt709), 3840x2160 [SAR 1:1 DAR 16:9] ....
On a different one, also x265 I get
[ffmpeg/video] hevc: ff_v4l2_request_query_control: query control failed, Invalid argument (22)
Probably just doing something wrong...