[FFmpeg-devel] [PATCH 21/28] added: make libavformat expose the FORCED flag from matroska as a disposition

[Aurelien Jacobs]

On Thu, Jul 01, 2010 at 11:34:20PM +0200, Michael Niedermayer wrote:
> On Thu, Jul 01, 2010 at 04:35:36PM +0200, Aurelien Jacobs wrote:
> [...]
> > Index: libavformat/avformat.h
> > ===================================================================
> > --- libavformat/avformat.h	(r?vision 23934)
> > +++ libavformat/avformat.h	(copie de travail)
> > @@ -396,6 +396,7 @@
> >  #define AV_DISPOSITION_COMMENT   0x0008
> >  #define AV_DISPOSITION_LYRICS    0x0010
> >  #define AV_DISPOSITION_KARAOKE   0x0020
> > +#define AV_DISPOSITION_FORCED    0x0040
> 
> what does forced mean?

Useful especially for subtitles.
For example, you are watching a movie with an english audio track, but
some short parts of the audio track contain some dialog in another
(possibly uncommon) language. User can enable english subtitles, to have
the whole movie subtitled. But if the user don't ask for subtitle, a
specific subtitle track containing only translation of the parts in
different language should be displayed. This specific subtitle track
would have AV_DISPOSITION_FORCED.
IIRC such a thing also exists on DVDs.

> this need doxy

Attached.

Aurel
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