[FFmpeg-devel] Format of decoded text subtitles

Nicolas George nicolas.george at normalesup.org
Thu Aug 2 11:26:38 CEST 2012

Le quintidi 15 thermidor, an CCXX, Clément Bœsch a écrit :
> I think that markup can be left unchanged to start with: no changes
> required in the decoders. And I also think we should follow Michael's
> recommendation about just extending the ASS markup to FFmpeg needs

If you really think it is better. What about simplifying markup: {\a2\fs25}
-> {\a2}{\fs25}? It may make work easier for non-ASS encoders.

> only one "important" I see in the pure markup thing is text justification;
> I don't think ASS has that). I'd propose to wait for the AS6
> specifications (ASS++) to see if we can't just follow it.

Do you know when it is due?

> I guess you'll hit some classic storage issues, such as how to make a sane
> key/value system for palettes for example. I can't think of much more
> things.

What do you mean exactly?

I realized that this proposal has an easy solution for transition: since
currently a lot of decoders fill the rect->ass field with a full ASS event
line, converting old encoders to the new format can be done in the wrapper

	if (rect->ass && !rect->rich_text) {
	    av_log(avc, AV_LOG_WARNING, "Please update the decoder\n");


  Nicolas George
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