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

Laurent Aimar fenrir
Sun Apr 11 22:25:07 CEST 2010


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.



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