libv4l-rkmpp

A V4L2 plugin that wraps rockchip-mpp for the chromium's V4L2 video decoder/VEA (requires custom patches to enable those features).

The original idea comes from v4l-gst.

Dependencies

   $ meson build
   $ meson compile -C build

Install libv4l-rkmpp.so into /usr/lib/libv4l/plugins/
Create dummy V4L2 device files for chromium V4L2 video decoder/VEA in boot service:

   # echo dec > /dev/video-dec0
   # chmod 666 /dev/video-dec0
   # echo enc > /dev/video-enc0
   # chmod 666 /dev/video-enc0

Configure codec capabilities

The codec capabilities (depends on chip spec) are configurable in device files:

   # cat /dev/video-dec0
   log-fps=1
   log-level=2
   type=dec
   codecs=VP8:VP9:H.264:H.265:AV1
   max-height=1920
   max-width=1080

   export XDG_RUNTIME_DIR=/run/user/0
   chromium --no-sandbox --gpu-sandbox-start-early --ignore-gpu-blacklist

This plugin is tested with custom chromium on rk3588 EVB.

There're a lot of chromium related hacks in it, might not work for other apps.

For proper decoding usage, there's a ffmpeg solution with a few extra buffer copies.

MPP reports errors?

Try the newest MPP release branch or develop branch or the commit with the closest commit date.

Also test with the mpi_dec_test to check if the MPP works:

# mpi_dec_test -t 7 -i test-25fps.h264

How to get more verbose logs?

For chromium, use these command line flags to change the log level: --enable-logging --vmodule=/media/gpu=4

For libv4l-rkmpp, set the "LIBV4L_RKMPP_LOG_LEVEL" environment variable to change the log level. And set "LIBV4L_RKMPP_LOG_FPS" to enable logging fps.

For MPP, set the environment variable "mpp_debug", "rkv_h264d_debug", "mpp_dec_debug", "mpi_debug", etc. to change the modules' log levels.

For vpu driver, write verbose log level to "/sys/module/rk_vcodec/parameters/debug".
What about the performance?

The performance should be much the same as other MPP based decoders/encoders (e.g. mpi_dec_test and gstreamer MPP plugin).

And the performance would mostly related to the video's attributes (e.g. resolution and bitrate) and the vpu clock rates.