[FFmpeg-devel] Stream with Closed caption does not set appropriate flag

Reimar Döffinger Reimar.Doeffinger at gmx.de
Sun Mar 9 00:29:23 CET 2014

On 09.03.2014, at 00:18, Nicolas George <george at nsup.org> wrote:
> Le sextidi 16 ventôse, an CCXXII, Reimar Döffinger a écrit :
>> Because we cannot currently extract it, and in general extracting CC
>> data as a separate stream is problematic since it is designed to be
>> reordered by the video decoder along with the image.
>> It's of course solvable but a bit of an effort.
> It was discussed during the last VDD: if the extraction is done by the
> decoder and the resulting captions attached to the frame as meta- or
> side-data, then the reordering is automatically done by the video
> processing.

But that doesn't help any with the problem here: we have no way to signal that a subtitle track is available from the demuxer, nor any of its parameters, or?

> Of course, that does not fit well in the protocol/demuxer/decoder stack
> model, but it is better than nothing, and I can see ways of making it
> actually useful for common tasks.

Better than nothing, sure. It's still crap, and it does not just "not fit well", but rather "it's barely usable". Can you even use it at all from command-line ffmpeg? ffplay? How about VDPAU (I guess it should still work, but not sure anyone tested)?

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