[MPlayer-dev-eng] [PATCH] Read normal duration when demuxing subtitles through lavf (v2)

[Philip Langdale]

On Wed, 1 Aug 2012 22:03:37 +0200
Nicolas George <nicolas.george at normalesup.org> wrote:

> Le quintidi 15 thermidor, an CCXX, Alexander Strasser a écrit :
> >   Maybe I am confused, but when testing I could not find a sample
> > that triggered the (convergence_duration > 0) condition. But I
> > rather saw many samples where (convergence_duration == 0) and
> > (duration != 0). Seems recent lavf does not set convergence_duration
> > that often.
> 
> Try putting that in a text file:
> 
> # 1
> # 00:00:01,000 --> 00:00:03,000
> # Hello world.
> # 
> 
> And then using mkvmerge to turn it into Matroska.

Yeah. The only place convergence_duration is used for subtitles is
in matroska UTF8/TEXT subtitles. This is a very common format, so
people see it all the time. Matroska ASS subtitles go through a
different path in mplayer, so are not effected.

In practice, when you look at what's actually in use, there are
very few formats that have text subtitles that pass through this
path in mplayer - mp4 files with timed text is one of them, and I
happen to have been working on those in ffmpeg, so I noticed they
were broken in mplayer.

It is, perhaps, a bold claim, but I firmly believe this change won't
make any subtitles worse.

--phil