[mythtv] Fwd: DVB subtitles and delay

[Kenni Lund]

2010/4/14 Mark Kendall <mark.kendall at gmail.com>:
> On 13 April 2010 03:54, Martin <martin.rene.mortensen at gmail.com> wrote:
>> MythTV has since the 0.22 ffmpeg sync not had great support for DVB
>> subtitles. They are delayed - and this off course has very low WAF.
>> Theres a bug report on it, fix is seemingly a somewhat large rewrite and has
>> been postponed to 0.24 now.
>> TRAC ticket 6753: http://svn.mythtv.org/trac/ticket/6753
>> Now I am wondering if there is not a work-around of some sort. There was
>> some suggestion that one could revert mpegts.c,h to one before the sync. But
>> this is not a very viable solution if you lose important features like
>> he-aac sound.
>> Do anyone have work-arounds for this? or are very few people using DVB
>> subtitles ?
>
> For what it's worth, I spent some time looking at that ticket a few
> weeks ago without much success.
>
> The problem lies somewhere between the broadcaster and ffmpeg's
> demuxing of the stream, with the net result that some subtitles arrive
> very late. I worked with the patch that Janneg posted to the ticket
> for queueing transmitted packets and that did generate some
> improvements but it certainly did not fix it and was far from a
> complete/commitable solution. There are various issues - though
> ideally this would be fixed within ffmpeg itself. Overall there is no
> simple fix that I can see that sits within the main MythTV code.

Mark, FYI it seems like the issue have been fixed in upstream FFMPEG.
I tested the clip from ticket #6753 with ffplay from FFMPEG SVN r22837
and AFAICT the subtitles are perfectly in sync, unlike in 0.23-fixes
or trunk.

Best Regards
Kenni