media: bcm2835-codec: Increase video callbacks limit

[popcornmix]

The previous commit limited callbacks to DPB+5.
This has been found insufficient for kodi and ffmpeg
decoding h.264. Increase to DPB+6

Fixes: f814bfc

Signed-off-by: Dom Cobley [email protected]

[popcornmix]

See discussion here
(and wait for confirmation that fixes @satmandu's issue).

It is possibly 7 may be needed, but lets wait and see.

Ping @jc-kynesim @6by9

[satmandu]

@popcornmix I'm getting the same issue as before when I apply https://patch-diff.githubusercontent.com/raw/raspberrypi/linux/pull/4658.patch to Top of tree rpi-5.15.y.

Trying a rebuild with 7...

[satmandu]

No luck even with it set to 7.

FYI vc-log gives me this:

[  297.297033] vcos: mmal: mmal_component_parameter_set: parameter id 0x00020038 not supported

Removing the -vcodec h264_v4l2m2m from the ffplay command line once again allows it to work.

[popcornmix]

@satmandu what does vcgencmd version report?

[satmandu]

Ah I have the default ubuntu firmware...

sudo vcgencmd version
Aug 31 2021 14:52:47
Copyright (c) 2012 Broadcom
version 67615e950e1e28b92dfae6303cf7a8b879a8908f (clean) (release) (start)

[satmandu]

With the newest firmware...

sudo vcgencmd version
Oct 28 2021 14:14:14
Copyright (c) 2012 Broadcom
version bcdfe55d56b75b4be52c10d73bdb4a60e2b49f75 (clean) (release) (start)

I get this from vc-log:

[  280.423679] unknown: video_decode:6:RIL: colourspace changing

And still the same breakage with no video to display.

ffplay version 4.4-6ubuntu5 Copyright (c) 2003-2021 the FFmpeg developers
  built with gcc 11 (Ubuntu 11.2.0-7ubuntu1)
  configuration: --prefix=/usr --extra-version=6ubuntu5 --toolchain=hardened --libdir=/usr/lib/aarch64-linux-gnu --incdir=/usr/include/aarch64-linux-gnu --arch=arm64 --enable-gpl --disable-stripping --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librabbitmq --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzimg --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-pocketsphinx --enable-librsvg --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
Input #0, rtsp, from 'rtsp://<rtsp URL>/live':0
  Metadata:
    title           : Session streamed by the WYZE Media Server
    comment         : live
  Duration: N/A, start: 0.000000, bitrate: N/A
  Stream #0:0: Video: h264 (Main), yuv420p(tv, bt709, progressive), 1920x1080, 20 fps, 20 tbr, 90k tbn, 40 tbc
  Stream #0:1: Audio: pcm_alaw, 16000 Hz, 1 channels, s16, 128 kb/s
[h264_v4l2m2m @ 0x7f7804f600] Using device /dev/video10
[h264_v4l2m2m @ 0x7f7804f600] driver 'bcm2835-codec' on card 'bcm2835-codec-decode' in mplane mode
[h264_v4l2m2m @ 0x7f7804f600] requesting formats: output=H264 capture=YU12

[jc-kynesim]

@6by9 does a colourspace change cause a format change event? If so I'm going to guess that that is a ffmpeg without proper support for that.

[6by9]

does a colourspace change cause a format change event?

Yes it does as it is part of the V4L2 format.

[satmandu]

If I need to be trying this with an ffmpeg binary built from raspi-os 64-bit that's fine too...

If someone can point me to the dsc file so I can rebuild that for ubuntu...

[6by9]

I'm not sure this will even have been fixed in Raspberry Pi OS, but I haven't seen issues.

https://github.com/FFmpeg/FFmpeg/blob/master/libavcodec/v4l2_context.c#L195 does not follow the specification given in https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/dev-decoder.html#dynamic-resolution-change.
It only does anything if the resolution has changed, but the spec gives no option:

A source change triggers an implicit decoder drain, similar to the explicit Drain sequence. The decoder is stopped after it completes. The decoding process must be resumed with either a pair of calls to VIDIOC_STREAMOFF() and VIDIOC_STREAMON() on the CAPTURE queue, or a call to VIDIOC_DECODER_CMD() with the V4L2_DEC_CMD_START command.

If neither of those is done (actually the codec doesn't support V4L2_DEC_CMD_START at present), then decode will be stopped waiting for it to happen.
reinit shouldn't be conditional on the return value from v4l2_resolution_changed(&s->capture, &cap_fmt);, it should always be 1.

[popcornmix]

No longer needed as "media: bcm2835-codec: Limit video callbacks" has been reverted.