[FFmpeg-devel] [PATCH]Add two v4l2 pix_fmts

[Carl Eugen Hoyos]

Stefano Sabatini <stefasab <at> gmail.com> writes:

> > > >      if (desired_format == V4L2_PIX_FMT_YVU420)
> > > >          st->codec->codec_tag = MKTAG('Y', 'V', '1', '2');
> > > > +    else if (desired_format == V4L2_PIX_FMT_YVU410)
> > > > +        st->codec->codec_tag = MKTAG('Y', 'V', 'U', '9');
> > > 
> > > why these exceptions?
> > 
> > They are needed both for decoding and remuxing YVU*.
> 
> Yes but why do they need to set a specific tag (as opposed to 
> the other formats), or in other works why are they special?

libswscale only supports yuv4xx, libavcodec and libavformat 
also support decoding and remuxing yvu4xx, the codec_tag 
is used to distinguish them from yuv4xx.

Carl Eugen