Hugh Cole-Baker

A couple of other reasons I can think of why it wouldn't work: Does the user you're running ffmpeg as have write permission on /dev/video*, /dev/media* and /dev/dri/card* devices? And did the compile time checks for v4l2_request support in FFmpeg pass? (you need to see v4l2_request under "External libraries providing hardware acceleration:", and h264_v4l2request under "Enabled hwaccels:", in the output of FFmpeg's configure script when you're compiling it). For the FFmpeg configure checks to pass, AFAIK you need the kernel headers from a recent kernel with v4l2-request support installed, e.g. kernel v5.6.

The h264_v4l2m2m decoder in FFmpeg is only for stateful decoders like the Amlogic VPU. The stateless decoders hantro and rkvdec use a different approach in FFmpeg, using the "h264" decoder but with hardware acceleration using v4l2-request API. Try using this ffmpeg command, which worked for testing decoding with the rkvdec on my rk3399 board: ffmpeg -loglevel debug -hwaccel drm -i bbb_sunflower_1080p_30fps_normal.mp4 -f null - or change the "-f null -" to "-pix_fmt bgra -f fbdev /dev/fb0" to output video to the Linux framebuffer device while X11 or Wayland aren't running, for example.

@piter75 Are you planning to send the ATF "switch power domains on before reset" patch upstream to https://review.trustedfirmware.org/ ? It fixes the issue with mainline ATF + Linux where Linux will hang after rebooting; I have tested the patch with my own custom build of Debian and it now reboots 100% successfully. It would be really useful for all mainline distros if it was applied to mainline ATF.