[FFmpeg-devel] [PATCH 1/2] lavf/subtitles: add ff_subtitles_queue_seek().

Clément Bœsch ubitux at gmail.com
Sun Dec 2 00:21:56 CET 2012

On Tue, Nov 27, 2012 at 04:26:00PM +0100, Michael Niedermayer wrote:
> > If we have a subtitle event starting at t=2sec, with duration=1hour,
> > followed by normal subtitles at a frequency of about 1000 subtitles per
> > hour, what happens if the seek at t=30min happens to actually seek at
> > t=2sec? What's gonna happen to the ~500 subtitles to keep up with the
> > current time? Remuxing them doesn't sound right, and same for making the
> > player display all of them as fast as possible.
> can we discard such "past" subtitles somewhere conveniently, so that
> effectively only the 1h and the actually relevant subtitles after that
> are used ?
> (that could be done efficiently in the demuxer or less efficiently
>  afterwards)
> > 
> > This is an extreme case, but similar situations are going to happen if we
> > start looking at solving these overlapping issues.
> > 
> > BTW, I'm a bit reluctant to changing this in this patch (I'm just
> > moving/copying the code to allow re-use it with all the subtitles format),
> > could we delay that feature, or you believe it's blocking?
> delay is fine, but it has to be dealt with at some point, and
> preferably before too much code uses the function because it may
> become more painfull then if something needs to be changed for all
> users

Applied, with the fix to handle overlapping subtitles.

Clément B.
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