[mythtv] audio waiting for buffer to fill

[Mark Spieth]

by the time it's transcoded its too late. on an untranscoded mpeg2 pts wrap,
you will get the effect for a short time and then it fixes itself.

to play an already transcoded dvb recording
use menu audio sync adjust 1 or 0 (I forget which is the right one) after
you get the affect in your transcoded stream.
this will adjust the audio timestamp to align with the video one.
I used to have an auto sync adjust but it had problems with xvmc apparently.
so this is now disabled. but the manual one is just as good just not
automatic.

if people are interested, I can make a patch which would allow the auto sync
adjust to be enabled via menu, but its not really necessary after you apply
the patch and transcode thereafter, unless your recording is > 26.5 hours
long.
cheers
mark

===================

I assume you mean http://cvs.mythtv.org/trac/ticket/113 ?

If so, I just patched that and it still does the exact same thing. Didn't
really sound like the problem anyway.

I have had 4 hour recordings that play just fine beginning to end. I can see
a little glitch in the picture on the latest problem file when the audio
problem kicks in. The latest one is still MPEG2 (51 minutes in) since the
transcoder failed (presumably from the same problem)

> -----Original Message-----
> From: mythtv-dev-bounces at mythtv.org
> [mailto:mythtv-dev-bounces at mythtv.org] On Behalf Of Mark Spieth
> Sent: Sunday, 17 July 2005 8:18 PM
> To: Development of mythtv
> Subject: Re: [mythtv] audio waiting for buffer to fill
>
>
> see my last ticket and patch (today's). it explains everything.
> cheers
> mark
>
> > 99% of the time my system works fine. However everynow and
> then I get a
> > recording (in this case an MPEG4 transcoded from DVB MPEG2)
> which seems to
> > have a glitch or something not quite right. From then on in
> the recording
> I
> > see the messages below in the log. At the same time the
> audio starts to
> > "stutter" and sync seems to get lost. This coincides with the "A/V
> > diverged..." messages. The A/V diverged messages seem to
> start just before
> > the buffer ones.
> >
> > If I Ctrl-Z to make mythfrontend stop and restart it will
> be fine for a
> > second or two and then go back to stuttering. The A/V
> diverged signals
> seem
> > to always be happening from that point on in the file though..
> >
> > I'm not sure where to look personally. I can provide a
> download of the
> file
> > for a developer however in this current file the stuttering
> doesn't start
> > until 15 minutes in. I only have 128kbps upstream so I'm
> not sure how
> > someone could easily get to the faulty part of the file. If
> someone wants
> > the file let me know.
> >
> > This is all with latest CVS (well SVN really) as of yesterday.
> >
> > Does anyone know what might be happening that could make a
> recording cause
> > audio buffering type problems happen?
> >
> > 2005-07-17 18:57:02.457 audio waiting for buffer to fill:
> have 3584 want
> > 4096
> > 2005-07-17 18:57:02.457 Broadcasting free space avail
> > 2005-07-17 18:57:02.463 audio waiting for buffer to fill:
> have 3584 want
> > 4096
> > 2005-07-17 18:57:02.463 Broadcasting free space avail
> > 2005-07-17 18:57:02.468 audio waiting for buffer to fill:
> have 3584 want
> > 4096
> > 2005-07-17 18:57:02.468 Broadcasting free space avail
> > 2005-07-17 18:57:02.474 audio waiting for buffer to fill:
> have 3584 want
> > 4096
> > 2005-07-17 18:57:02.474 Broadcasting free space avail
> > 2005-07-17 18:57:02.483 audio waiting for buffer to fill:
> have 3584 want
> > 4096
> > 2005-07-17 18:57:02.483 Broadcasting free space avail
> > 2005-07-17 18:57:02.488 audio waiting for buffer to fill:
> have 3584 want
> > 4096
> > 2005-07-17 18:57:02.488 Broadcasting free space avail
> > 2005-07-17 18:57:02.493 audio waiting for buffer to fill:
> have 3584 want
> > 4096
> > 2005-07-17 18:57:02.494 Broadcasting free space avail
> > 2005-07-17 18:57:02.500 audio waiting for buffer to fill:
> have 3584 want
> > 4096
> > 2005-07-17 18:57:02.500 Broadcasting free space avail
> > 2005-07-17 18:57:02.505 audio waiting for buffer to fill:
> have 3584 want
> > 4096
> > 2005-07-17 18:57:02.505 Broadcasting free space avail
> > 2005-07-17 18:57:02.517 A/V diverged by 30 frames,
> extending frame to keep
> > audio in sync
> > 2005-07-17 18:57:02.521 A/V diverged by -30 frames,
> dropping frame to keep
> > audio in sync
> > 2005-07-17 18:57:02.525 A/V diverged by -30 frames,
> dropping frame to keep
> > audio in sync
> >
> >
>
>
> --------------------------------------------------------------
> --------------
> ----
>
>
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