[mythtv-users] Sound Syncronization Problems in Recording Playback ONLY

Douglas Wagner douglasw0 at gmail.com
Tue May 16 18:15:00 EDT 2006


Ok,

     I've accepted my fate.  I'm GOING to get yelled at for posting this.  I
know for a fact i've seen this issue come up several times in the recent
past but for the LIFE of me I can't find the threads.  So, i'm going to ask
this again.

Problem:  When I try to play back a recorded ATSC HDTV show (only those, it
seems, shown in high def, see "oddities" next) the audio lags behind the
video by about 3 to 5 seconds.  Meaning that you see the people on the
screen speaking and then hear the audio.  The problem GOES AWAY if I drop
out of mythtv, and load the recorded video through Xine.  So, my solution so
far has been to go into MythTV, to the recorded shows section, find the show
and date, and then go to my video directory and use xine to play it.  Of
course this cuts out my remote (I don't have xine setup on it yet) and the
nifty features of MythTV, so i'm really not liking the solution.

Oddities: Several:  1) this happens ONLY on shows recorded in true HD.  My
PBS Shows, which are shown in HD but only come out to about 600 Meg in size
(while a show of the same length on ABC Comes out to about 6 - 7 Gig), work
just fine when played back via Myth.  So, Callou and Clifford for my kids
are fine but alias and boston legal all lag sound (for instance).
2) When i'm OUT of mythtv another player plays the audio/video just fine, so
it has something to do with how Mythtv is streaming the audio in to the
video.  As I said above xine has no problem.  I guess more to the point,
it's how MPlayer streams audio/video as I think that's the default setup for
Myth playback.
3) This DOES NOT happen in live TV, when myth is playing live TV everything
works JUST fine.  Sound/Video syncronization is no issue.
4) THIS WORKED!!! I've not upgraded, i've not changed settings, i've not
done anything I can think of (I did have to re-setup myth due to a database
channel issue, but I THOUGHT I set it back the same way).

Hardware: pcHDTV 3000 card with ATSC Signal connected directly to it,
nothing comming out of the card (audio and video are recorded streamed over
the PCI bus, not using any patch wires).  Fedora Core 5, Pentium IV
2.8GHyper-Threaded, 1G memory, ~400g harddrive, all 7200 RPM (IDE, not
SATA).
Soundblaster Live! Value Digital sound card.

Software: MythTV v0.19, Kernel Version 2.6.16_2096 SMP.  Mplayer I believe
is setup as the default playback software for recorded streams (it's the
default setting, I don't think i've mucked with anything).

HELP!  I REALLY don't want to have to keep dumping out of MythTV to play
recorded shows.  I'm going to try to re-setup myth to use Xine via the WIKI
instructions sometime later this week, but for the moment, i'm hopelessly
lost.  I'm SURE it's something stupid.  Oh, and no, pausing and restarting
doesn't seem to help either.

Any assistance would be MOST apprecaited.

--Douglas Wagner
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