[FFmpeg-devel] [RFC] Implementation of closed caption support

Kieran Kunhya kierank at obe.tv
Mon Aug 4 21:18:11 CEST 2014

> Uh, no.
> The point is to get the CC data out you need to decode.
> Now that you have the video decoded, if you want to mux it you have
> to encode it again.

Whether you decode the video or not is unrelated to your ability to
replace the SEI and replace the captions.
You'd still need to know the reordering though.

Unless you are talking about mov which is the only container that has
a special closed captions stream.

> Yes, that's one of the things that make it complex to implement.
> But the parser certainly has all the information to do the reordering.

It would have to do some low-level parsing to handle complex b-frame
patterns. VLC uses a guessed B-frame pattern and as a result is not
frame accurate.

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