[mythtv-users] Major Audio Sync Issues

[Mark Small]

On November 18, 2009 21:29:11 Paulin wrote:
> On Wed, Nov 18, 2009 at 5:24 PM, Paulin <paulin at spextreme.com> wrote:
> > On Wed, Nov 18, 2009 at 3:13 PM, Mark Greenwood 
<fatgerman at ntlworld.com>wrote:
> >> On Wednesday 18 Nov 2009 02:08:05 Paulin wrote:
> >> > I'm been banging my head against the wall on this issue for a couple
> >> > of
> >>
> >> days
> >>
> >> > now.  I've search the thread and google for anything I can find on
> >> > Audio
> >>
> >> Out
> >>
> >> > Of Sync and I've tried a ton things.   No luck with any of it.
> >> >
> >> > I upgrade last week to Mythbuntu 9.10 (myth 0.22).  I'm using VDPAU.
> >> > Before upgrading I didn't really have this issue.
> >> >
> >> > When I say upgraded I basically wiped the disk and started fresh.
> >> >
> >> > Anyway now the Myth Recordings that are occurring seem fine.  However
> >>
> >> when
> >>
> >> > playing back the audio and video become out of sync.  I've noticed
> >> > that
> >>
> >> the
> >>
> >> > video will attempt to slow down to let the audio catch up but it never
> >>
> >> stays
> >>
> >> > there.  They get out of sync and evenytually get really bad (few
> >>
> >> seconds).
> >>
> >> > I've tried changing the player to VLC, I also tried the suggestion on
> >> > (
> >>
> >> http://mythtvbox.blogspot.com/2006/01/fixing-mythvideos-audiovideo-sync.
> >>html )
> >>
> >> > and put oss on the mplayer command string.  I also setup XvMC per the
> >>
> >> wiki
> >>
> >> > page.  Didn't change anything.
> >> >
> >> > My first question is, how do I enable extended logging on myth
> >> > frontend using mythfrontend.real.   I remember something about adding
> >> > the
> >>
> >> parameter
> >>
> >> > 'playback' but not sure how to do that with mythfrontend.real.
> >> >
> >> > Second why is my audio/video so out of sync? How do I track down the
> >>
> >> problem
> >>
> >> > and fix it.
> >> >
> >> > Thanks
> >> > steve
> >>
> >> Have you tried enabling the setting 'Use Video As Timebase', somewhere
> >> amongst the reams of setup screens, TV playback I think? I did this for
> >> a similar problem, also with VDPAU, and it solved it.
> >>
> >> Mark
> >> _______________________________________________
> >> mythtv-users mailing list
> >> mythtv-users at mythtv.org
> >> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
> OK well here is an updated.
>
> Use Video as time base causes the video to slow to a crawl and play really
> weird.  I have Enable RealTime checked, Extra Audio Buffer check ,and warn
> on no audio.  I'm using VDPAU SLIM.
>
> It seems to happen mostly with recorded programs but not all. and
> not consistently.  When the problem occurs, I've seen the video slow down
> while the audio catches up.  I've also seen where the mouths talking is out
> of sync with audio.  Last night watching Castle and V was the worst.  At
> some points the video was 3 to 4 seconds out of sync.  Commercial skipping
> causes it to get closer.
>
> I did see the problem watching through myth video but that wasn't too bad
> (half  second off).
>
> Also processing power of the node when watching a program is about 8% CPU
> usage.  Commercial flagging running would spike around 70% (62% flagging).
>  Recording also going on.  So processing wise it should be safe (2.2ghz
> dual core)
>
> So what have I tried,
> Different players and player options (mplayer, vlc).
> Playing the video elsewhere (copied mpg to a windows machine played fine)
> Played with xorg.conf but didn't change anything.
> Host of other little things here and there as I found online.
>
> On a possible related note, I have the following issues occur and I'm not
> sure if it could be hardware/configuration/or NVidia driver.
> - While watching a video or recording, the screen just goes blank.   Audio
> continues but there is no picture.  Like the TV lost the signal.  I have to
> restart GDM to get it back up.
> - Sometimes after restarting GDM it comes back up and the entire picture is
> distored.  Like each line (pixel row) is skewed (if that is the best
> description) so the entire picture is impossible to determine.  At one
> point I went to the desktop and popped up the NVidia config.  It looked
> like normal but if I moved it, it became pixellated (like using photoshop's
> noise feature).
>
> So any ideas or ways to fix this.  I didn't have these issue in the Myth
> 0.21 that I built from trunk. So I think everything (hardware) should be
> fine.
>
> I'm desperate and frustrated so I'm willing to try any ideas to fix this.
>
> Thanks
> steve

I've also been seeing audio sync issues.  The weird thing is that it only 
seems to happen on ABC programs (Ugly Betty, Flashforward).  This doesn't 
make sense to me since I'm recording analog on a PVR250.  The station 
shouldn't make a difference, unless its a source issue.

This may be a completely different issue to yours.
I'm still running 0.21. I'm recording through a Motorola STB on an analog 
channel with Composite output from the box.  I haven't done any investigating 
or changed any settings yet.

Mark