[FFmpeg-user] How to set V4L2 M2M codec options like bitrate

[Andriy Gelman]

On Sun, 15 Aug 2021 at 10:15, Adam Nielsen <a.nielsen at shikadi.net> wrote:

> > > I'm using the h264_v4l2m2m codec to do hardware accelerated encoding on
> > > a Raspberry Pi.  This is working well, except I am unable to set any
> > > encoder options such as bitrate, as I cannot find how to tell ffmpeg to
> > > set V4L2 control options.
> >
> > You can use -b:v option to set the bitrate, i.e.
> > ./ffmpeg -i input -codec:v h264_v4l2m2m -b:v 2M out.mp4
> >
> > There is a patch for documentation that I need to update. It may be
> useful
> > to you:
> >
> https://patchwork.ffmpeg.org/project/ffmpeg/patch/20200117034211.12142-1-andriy.gelman@gmail.com/
>
> Ah excellent, many thanks for that, that does work for setting the
> bitrate.
>
> Unfortunately the most important option I need to change is the
> "repeat_sequence_header" control, which I need to set to 1 as the
> default of 0 means if you miss the initial frame of the video, you can
> never join the stream mid-way through, as ffplay just produces heaps of
> "non-existing PPS 0 referenced" messages and never opens the video
> window.
>
>

> Does this option have an equivalent to set on the ffmpeg command line,
> now v4l2-ctl will no longer work?


Not yet.
Can you test the attached patch, please? It will init the
repeat_sequence_header option to 1.

Thanks,
Andriy
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