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

[Michael Niedermayer]

On Sat, Mar 31, 2018 at 09:54:01AM +0300, Timo Teras wrote:
> Hi
> 
> On Sat, 31 Mar 2018 02:13:14 +0200
> Michael Niedermayer <michael at niedermayer.cc> wrote:
> 
> > On Thu, Mar 29, 2018 at 09:45:13AM +0300, 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.
> > [...]
> > 
> > > @@ -5480,6 +5529,24 @@ static int mov_write_packet(AVFormatContext
> > > *s, AVPacket *pkt) if (!pkt) {
> > >          mov_flush_fragment(s, 1);
> > >          return 1;
> > > +    } if (s->streams[pkt->stream_index]->disposition &
> > > AV_DISPOSITION_ATTACHED_PIC) {  
> > 
> > The if() should be in the next line or it should be a else if
> > it looks like someone forgot a "else" even though it makes no
> > difference here.
> 
> Thanks. Will fix this, and have few other minor cleanups too. Will
> resend, but I have additional questions/notes too:
> 
> I think I will audit all for (...; ... < mov->nb_streams; ...) loops
> to see if they need to skip these attachments. In most cases it's
> implicitly done because they don't get track->entry incremented now.
> However, there might be few off especially with empty_moov flag.
> 

> Wondering also if all those "track->entry <= 0" checks should be made
> to static inline function mov_track_has_data() or similar?

sounds like a good idea


> 
> Any comments if the patch should be split e.g. adding the attached_pic
> flag on it's own?

yes, that certainly should be split into a seperate patch


> 
> Or if the code in mov_write_packet() to stuff the received data to the
> buffers should be in generic code, or made a helper function?

If it can be shared it could be in common code. yes

> 
> And finally, should the codec tag/type negotiation code somehow be
> updated to recognize attachment_pic and accept only the valid three
> image formats supported for now? If yes, how to do it?
> 
> Thanks,
> Timo
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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