[mythtv-users] DVB subtitles and delay

Kenni Lund kenni at kelu.dk
Mon Apr 19 22:19:02 UTC 2010


2010/4/15 Jeppe Nejsum Madsen <jeppe at ingolfs.dk>:
> On Thu, Apr 15, 2010 at 12:32 PM, Kenni Lund <kenni at kelu.dk> wrote:
>> 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
>> <SNIP>
>>> 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, I just did a quick test with FFMPEG SVN r22837 and when playing
>> the clip in ticket #6753 with ffplay, the subtitles are close to, if
>> not perfectly, in sync :) So it seems like this have been fixed in
>> upstream FFMPEG...
>
> That is good to know :-) Could be interesting to try this with the
> ffmpeg rev used in myth, just to verify that it is indeed an ffmpeg
> issue...

Unfortunately, it's not a FFMPEG bug after all, it's a MythTV bug:
http://mythtv.org/pipermail/mythtv-dev/2010-April/068221.html

Best Regards
Kenni


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