[mythtv-users] ATSC Encoder change breaks Mythtv

[Greg Maus]

Taylor,
On Fri, 2010-10-08 at 23:12 -0400, Taylor Ralph wrote:
> Greg,
> 
> On Fri, Oct 8, 2010 at 7:30 PM, Greg Maus <g.maus at fnmmail.com> wrote:
> > Taylor,
> >
> > On Fri, 2010-10-08 at 14:30 -0400, Taylor Ralph wrote:
> >> Greg,
> >>
> >> On Fri, Oct 8, 2010 at 6:28 AM, Greg Maus <g.maus at fnmmail.com> wrote:
> >> > On Thu, 2010-10-07 at 21:06 -0400, Taylor Ralph wrote:
> >> >> On Thu, Oct 7, 2010 at 7:41 PM, Greg Maus <g.maus at fnmmail.com> wrote:
> >> >> >
> >> >> >> Have you tried playing back the video files in another player
> >> >> >> (MPlayer,
> >> >> >> VLC, etc). What format is the audio stream in (MPlayer will tell
> >> >> >> you)?
> >> >> >> What is your audio output configuration? That information will
> >> >> >> certainly
> >> >> >> help.
> >> >> >
> >> >> > The recorded files that will not play in Myth frontend play fine in all
> >> >> > of the common media players.  I am not exactly sure what you mean what
> >> >> > format is the audio stream.  I know that it is AC3, and that is the same
> >> >> > audio format as files that were recorded prior to the encoder change.
> >> >> > Is there a command line option in mplayer to get more specific audio
> >> >> > stream info?
> >> >> >
> >> >> > My Mythtv audio config is pretty basic.  ASLA:default.  I have also
> >> >> > tried ALSA:spdif, but there is no difference in playback regardless of
> >> >> > the settings.
> >> >> >
> >> >>
> >> >> You need to provide a small sample so a dev can take a look at what's going on.
> >> >>
> >> >> Regards.
> >> >> --
> >> >> Taylor
> >> >> _______________________________________________
> >> >> mythtv-users mailing list
> >> >> mythtv-users at mythtv.org
> >> >> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> >> >
> >> > A sample file has been uploaded here:
> >> > http://filebin.ca/mhvyt/KSTP_5.1sample.mpg
> >> > Thank you!
> >> >
> >>
> >> I've analyzed this video and unfortunately the FFmpeg mpegts demuxer
> >> doesn't provide any valid video timestamps (DTS or PTS). Obviously,
> >> this makes A-V sync impossible to accomplish. In mplayer the video
> >> plays fine with perfect A-V sync but by default it doesn't use the
> >> FFmpeg mpegts demuxer. So it is most likely a valid video format.
> >> FFmpeg prints the following error when processing the video:
> >>
> >> [mpegts @ 0x93da2c0]invalid dts/pts combination
> >>
> >> The only way to get this resolved is to file a bug report at
> >> http://ffmpeg.org/bugreports.html and provide the sample which you've
> >> already created. Then open a ticket at
> >> http://svn.mythtv.org/trac/newticket and reference the FFmpeg ticket.
> >> Sorry I don't have better news but the sooner we get this fixed the
> >> better since I can only imagine other broadcasters will start using
> >> this new encoder at some point.
> >>
> >> Regards.
> >>
> >> --
> >> Taylor
> >> _______________________________________________
> >> mythtv-users mailing list
> >> mythtv-users at mythtv.org
> >> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> >
> > I have opened tickets:
> > FFmpeg Issue2286
> > Mythtv #9076
> >
> > I mentioned your name as helping me to find the problems in the file.  I
> > hope this is okay.
> >
> > Thank you,
> > Greg
> >
> 
> Thanks for providing the sample and bug reports.
> 
> This should now be fixed in trunk and 0.23-fixes.
> 
> Baptiste is correct that the file is technically broken but their
> solution is a bit extreme for a player since it has to have a valid
> video timestamp for A-V sync purposes. You might want to forward the
> information in the roundup ticket to your broadcaster so they can
> report the issue to the maker of the encoder.
> 
> Regards.
> 
> --
> Taylor
> _______________________________________________
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> mythtv-users at mythtv.org
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Thank you for your help with this.  The fix provided does indeed resolve
this issue.  I will let the engineer at KSTP know what you found, and
that he should let Harmonic know that encoding video without a timestamp
is not probably not a good idea.