Re: A problem with H.264 video (DVB-T)

> > Le Saturday 01 November 2008 05:22:55 Pavel Troller, vous avez écrit :
> > > Hi!
> > >   I have the following problem with playing H.264 (MPEG4) video from DVB-T
> > > stream:
> > >   When the channel is tuned, the video is played perfectly, without any
> > > problems. However, about 30 - 60 seconds later, the video starts to skip.
> > > At first, it stops momentarily and then skips the missing frames for about
> > > every 2 - 3 seconds, so it is very annoying (it still plays smoothly
> > > between the skips, every skip takes about 200 ms). The skip intervals
> > > decrease by the time, and of course also the difference between picture
> > > contents before and after the skip. After about a minute, it skips very
> > > often with very short skips, so it looks as a low framerate (about 10 fps).
> > > This is the final state, it continues to play this way until the channel is
> > > re-tuned, which resumes smooth playing for the next 30 - 60 seconds and
> > > then it repeats the whole process.
> > >   The sound is played continuously, no skips, and it keeps approximately
> > > in sync with the video.
> > >   This is not a CPU performance problem - CPU load doesn't hit 1.00 and it
> > > is a dualcore machine, so there is a big reserve in the CPU power.
> > >   Using kaffeine as a frontend. Formerly used xine-lib-1.1.15 and ffmpeg
> > > svn from the beginning of September, now tried with current hg snapshot of
> > > xine-lib and svn snapshot of ffmpeg. Still the same. I've been also playing
> > > extensively with various xine engine settings (quality of postprocessing,
> > > deinterlacer type, codecs priority etc.), and it didn't influence anything,
> > > the problem appears always in the same manner.
> > >   There isn't any debug/error output from xine-lib/ffmpeg.
> > >   Any help, what to fix ?
> > >     With regards, Pavel Troller
> > 
> > Could you provide a sample?
> > 
> > 
> I'm afraid not. I've recorded about 5 minutes of the HD stream, which played
> poorly from the air, but I've found that the recording plays smoothly all the
> time, with no problems at all! So I'm not able to reproduce the problem from
> a file, just direct playing from the DVB-T device is causing troubles, captured
> file is good and can be played without problems.
> 
Hi!
  I've found that I can play HD streams forever with no skipping - it's just
enough to activate the time shift feature for a second or two, and it plays the
stream, buffered by the time shift file, perfectly. It's the definitive evidence
that this problem is not caused by lack of CPU power - in this mode, the system
is loaded more than when just playing from the DVB device, because it has to write
the time shift file and play it back simultaneously. The only thing I have to
remember, is to erase the time shift file manually (I didn't find an option in
kaffeine to erase it automatically).
  I've tried to change number of video buffers and frames in the xine engine
settings, and it doesn't influence anything, the problem appears in approximately
the same time for 500 buffers as well as for 4000.
  WIth regards, Pavel Troller

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