[FFmpeg-devel] [PATCH] attachments support in matroska demuxer

Aurelien Jacobs aurel
Thu Jan 17 01:52:51 CET 2008

Evgeniy Stepanov wrote:

> On Thursday 17 January 2008 03:00:26 Aurelien Jacobs wrote:
> > OK. Here are things issues in this patch:
> >  - CODEC_TYPE_NB must stay at the end of the enum.
> >  - Adding attachments to AVFormatContext is probably a leftover from
> >    your previous patch.
> >  - I don't like the fake MATROSKA_TRACK_TYPE_ATTACHMENT and
> > everything depending on it.
> I was not 100% sure that it is safe to create av_streams at that
> point. The code somehow suggested that av_streams and MatroskaTracks
> are always kept in sync. If they are not, your variant is obviously
> better.

When we create MatroskaTracks, we don't have all the needed informations
to create the av_streams. That's why there is a temporary storage.
(and maybe because some track information which don't fit in av_stream
are needed by the demuxer, but I'm not sure).
I guess all of this MatroskaTracks could be simplified (removed ?), but
I never gave it a deep look.
Anyway, for attachments it's safe to not use MatroskaTracks.

> >  - I don't think CODEC_ID_ATTACHMENT is of any use if it's used for
> >    every kind of attachement. CODEC_TYPE_ATTACHMENT already gives
> > the same information.
> >
> > I fixed all those issues in the attached patch.
> >
> > Moreover, I tried to associate a specific CODEC_ID_* to different
> > kind of attachements. To me, this seems like a good idea, but I
> > would like to know what others think about it ?
> I just want to point out that it is a partial solution:
> ff_mkv_mime_tags surely does not contain everything that can possibly
> come as an attachment.

Sure, it was not meant to be complete. It's just the types I found in
2 random mkv files. Other types can be added later (patch welcome).


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