Dne torek, 01. oktober 2019 ob 00:43:34 CEST je Hans Verkuil napisal(a): > On 10/1/19 12:27 AM, Jernej Škrabec wrote: > > 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? > > Argh, I forgot about the fact that this uses requests. > > The FLUSH should happen *after* the MEDIA_REQUEST_IOC_QUEUE ioctl. Otherwise > it has no effect. As long as the request hasn't been queued, the buffer is > also not queued to the driver, so out_vb will indeed be NULL. Well, flush cmd has effect if it is called before MEDIA_REQUEST_IOC_QUEUE ioctl as it can be seen from linked dmesg output. I guess there is nothing that we can do to prevent wrong usage? BTW, if capture buffer is marked as done, shouldn't be also removed from the queue? Best regards, Jernej > > Sorry for the confusion. > > Regards, > > Hans > > > 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(-) _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
