[FFmpeg-devel] Add mpeg user_data CEA-608/708 extraction.

Michael Niedermayer michaelni
Sun Apr 11 23:24:35 CEST 2010

On Sun, Apr 11, 2010 at 10:25:07PM +0200, Laurent Aimar wrote:
> Hi,
> On Sun, 2010-04-11 at 15:49 -0400, Ronald S. Bultje wrote:
> > But is it part of a generic video frame then? I mean, you appear to
> > put this "thing" in AVPicture, suggesting that it can be part of any
> > picture, be that Sorensen-3, MPEG-4, Theora or raw YUV video.
> > 
> > My suggestion, again, would be to put it in its own stream, so that
> > packets have timestamps and the stream has a mediatype ("CEA-[67]08"),
> > which is a subtitle stream with fonts, glyphs, windows etc. The MPEG-2
> > demuxer would need to split it, and the MPEG-2 muxer would re-join it.
> > Your application wouldn't know any better than if it were a Matroska
> > stream with SSA subtitles.
>  Closed Captions data are usually embed inside the user data of the
> elementary video streams. This make it very hard to extract them at the
> demuxer level:
>  - You have to parse the video stream (mpeg-2 and h264) to extract them
>  - You have to reorder them as the video decoder would do for the
> associated video frame.
>  - You have to know the timestamp of the associated video frame to give
> them one.

yes, the design sucks and it doesnt seem we can fix that. so in AVFrame
it will have to go unless someone manages to cleanly put them in a
seperate stream but i dont see how that would be possible


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I have never wished to cater to the crowd; for what I know they do not
approve, and what they approve I do not know. -- Epicurus
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