Sam,

I tested it the same way, but I get the error message.

Decoder h264 does not support device type vaapi.
HW device init failed, using SW decode.
file:/home/spc/cin-test/aerial-shot-of-las-vegas-sprawl-daytime_w18wevlbr__D.mp4
 err: Success

I "sort of" forgot to mention an important part -- when ffmpeg can not use vaapi to decode a specific file, it backs down to using the software instead which is what the above message indicates.  So I think it is really working for you -- check CPU % usage with "top" with and without CIN_HW_DEV to see the difference.  Also, try it with MIXERS and you should see an obvious speedup.

For example, awhile back you provided us a test case of 150 clips (cin_media) and a few of these could not be loaded by ffmpeg using the GPU (in this case 5 out of 150) and it will use "SW decode" (software instead).  So you will see from the 150, the following:

Failed to get HW surface format.
HW device init failed, using SW decode.
file:/proj/cin_media/aerial-of-empire-s...mp4
  err: Success
...
file:/proj/cin_media/aerial-over-hoboken...mp4
file:/proj/cin_media/aerial-zoom-to-empire...mp4
file:/proj/cin_media/empire-state-...mp4
file:/proj/cin_media/freedom-tower-...mp4

GG did test this successfully on Leap but of course with different hardware.   gg/phyllis