Dne ponedeljek, 30. september 2019 ob 10:10:48 CEST je Hans Verkuil napisal(a): > On 9/29/19 10:00 PM, Jernej Skrabec wrote: > > This series adds support for decoding multi-slice H264 frames along with > > support for V4L2_DEC_CMD_FLUSH and V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF. > > > > Code was tested by modified ffmpeg, which can be found here: > > https://github.com/jernejsk/FFmpeg, branch mainline-test > > It has to be configured with at least following options: > > --enable-v4l2-request --enable-libudev --enable-libdrm > > > > Samples used for testing: > > http://jernej.libreelec.tv/videos/h264/BA1_FT_C.mp4 > > http://jernej.libreelec.tv/videos/h264/h264.mp4 > > > > Command line used for testing: > > ffmpeg -hwaccel drm -hwaccel_device /dev/dri/card0 -i h264.mp4 -pix_fmt > > bgra -f fbdev /dev/fb0 > > > > Please note that V4L2_DEC_CMD_FLUSH was not tested because I'm > > not sure how. ffmpeg follows exactly which slice is last in frame > > and sets hold flag accordingly. Improper usage of hold flag would > > corrupt ffmpeg assumptions and it would probably crash. Any ideas > > how to test this are welcome! > > It can be tested partially at least: if ffmpeg tells you it is the last > slice, then queue the slice with the HOLD flag set, then call FLUSH > afterwards. This should clear the HOLD flag again. In this case the queued > buffer is probably not yet processed, so the flag is cleared before the > decode job starts. > > You can also try to add a sleep before calling FLUSH to see what happens > if the last queued buffer is already decoded.
Ok, I tried following code: https://github.com/jernejsk/FFmpeg/blob/flush_test/libavcodec/ v4l2_request.c#L220-L233 But results are not good. It seems that out_vb in flush command is always NULL and so it always marks capture buffer as done, which leads to kernel warnings. dmesg output with debugging messages is here: http://ix.io/1Ks8 Currently I'm not sure what is going on. Shouldn't be output buffer queued and waiting to MEDIA_REQUEST_IOC_QUEUE which is executed after flush command as it can be seen from ffmpeg code linked above? Best regards, Jernej > > Regards, > > Hans > > > Thanks to Jonas for adjusting ffmpeg. > > > > Please let me know what you think. > > > > Best regards, > > Jernej > > > > Changes from v1: > > - added Rb tags > > - updated V4L2_DEC_CMD_FLUSH documentation > > - updated first slice detection in Cedrus > > - hold capture buffer flag is set according to source format > > - added v4l m2m stateless_(try_)decoder_cmd ioctl helpers > > > > Hans Verkuil (2): > > vb2: add V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF > > videodev2.h: add V4L2_DEC_CMD_FLUSH > > > > Jernej Skrabec (4): > > media: v4l2-mem2mem: add stateless_(try_)decoder_cmd ioctl helpers > > media: cedrus: Detect first slice of a frame > > media: cedrus: h264: Support multiple slices per frame > > media: cedrus: Add support for holding capture buffer > > > > Documentation/media/uapi/v4l/buffer.rst | 13 ++++++ > > .../media/uapi/v4l/vidioc-decoder-cmd.rst | 10 +++- > > .../media/uapi/v4l/vidioc-reqbufs.rst | 6 +++ > > .../media/videodev2.h.rst.exceptions | 1 + > > .../media/common/videobuf2/videobuf2-v4l2.c | 8 +++- > > drivers/media/v4l2-core/v4l2-mem2mem.c | 35 ++++++++++++++ > > drivers/staging/media/sunxi/cedrus/cedrus.h | 1 + > > .../staging/media/sunxi/cedrus/cedrus_dec.c | 11 +++++ > > .../staging/media/sunxi/cedrus/cedrus_h264.c | 11 ++++- > > .../staging/media/sunxi/cedrus/cedrus_hw.c | 8 ++-- > > .../staging/media/sunxi/cedrus/cedrus_video.c | 14 ++++++ > > include/media/v4l2-mem2mem.h | 46 +++++++++++++++++++ > > include/media/videobuf2-core.h | 3 ++ > > include/media/videobuf2-v4l2.h | 5 ++ > > include/uapi/linux/videodev2.h | 14 ++++-- > > 15 files changed, 175 insertions(+), 11 deletions(-)
