[FFmpeg-devel] [PATCH v2] avformat/movenc: support writing iTunes cover image

[Timo Teras]

On Mon, 16 Apr 2018 10:53:43 -0300
James Almer <jamrial at gmail.com> wrote:

> On 4/14/2018 3:32 PM, Timo Teräs wrote:
> > Fixes https://trac.ffmpeg.org/ticket/2798
> > 
> > This makes movenc handle AV_DISPOSITION_ATTACHED_PIC and write
> > the associated pictures in iTunes cover atom. This corresponds
> > to how 'mov' demuxer parses and exposes the cover images when
> > reading.
> > 
> > Most of the existing track handling loops properly ignore
> > these 'virtual streams' as MOVTrack->entry is never incremented
> > for them. However, additional tests are added as needed to ignore
> > them.
> > 
> > Tested to produce valid output with:
> >   ffmpeg -i movie.mp4 -i thumb.jpg -disposition:v:1 attached_pic \
> >          -map 0 -map 1 -c copy movie-with-cover.mp4
> > 
> > The cover image is also copied correctly with:
> >   ffmpeg -i movie-with-cover.mp4 -map 0 -c copy out.mp4
> > 
> > AtomicParseley says that the attached_pic stream is properly
> > not visible in the main tracks of the file.
> > 
> > Signed-off-by: Timo Teräs <timo.teras at iki.fi>
> > ---
> > v2:
> > - Store the image in MOVTrack->cover_image instead of
> >   AVStream->attached_pic per review request  
> 
> This is failing when i try to mux a jpg as cover art into m4a (Ipod
> muxer). It complains about missing codec tag for mjpeg. Is the covr
> atom valid for that format?

Yes, it's valid for m4a.

> Adding an entry to codec_ipod_tags[] may fix it, but that alone would
> probably then allow non cover art video tracks using that codec,
> which i assume is undesirable.

For audio formats, e.g. mp3, query codec returns MKTAG('A', 'P', 'I',
'C') to indicate that the image works only as attached picture.

But even for video formats, it would be nice if query codec can
properly tell which image formats it does based on disposition. The
codec list for cover images is different from generic video streams.

Any suggestions how to do that properly?

Timo