The state of mainline hardware decoding

[sigmaris]

ways to tell v4l2 to list all supported codecs/formats. Somehow, v4l2-dbg just does nothing or straight up ruins my terminal by writing binary to it. Good tool. All I want is "vainfo" but for v4l2-requests

There isn't exactly a list, but try listing the controls on each device with

Code:

v4l2-ctl --list-ctrls --device /dev/video0

You can check if they have controls for MPEG2, VP8, VP9, H.264, H.265.

anecdotes of using v4l2-requests on any rk3328 on some upstream kernel

At the moment not all of v4l2-request in the upstream kernel is stable uAPI yet, and drivers are still in staging. So for the best results, not-yet-upstream patches are useful. I have been using the kernel and ffmpeg patches used in LibreELEC in my media centre RockPRO64. Hardware decoding works OK, though I haven't tried VP8 recently - only MPEG-2, H.264 and H.265. But as I recall when I tried VP8 a few months ago it worked. I know that is RK3399 not RK3328, but they both have the hantro and rkvdec video decoder IP blocks.

The key thing is to get FFmpeg libraries that work with the kernel API of the kernel you're running. Hence the usefulness of LibreELEC as they are both maintained in the same project there: https://github.com/LibreELEC/LibreELEC.tv/