[mythtv-users] LiveTV and Recorded shows audio sync problems.

[Sergio Tashdjian]

I'm using an Analog V4l capture card, which is an Encore ENLTV-FM with
chipset saa7134 (philips i think).
Audio out on the capture card goes to my sound card line in with a cable.
Alsa is set to capture from line in, and line in is muted so it goes through
mythtv.

If i start livetv and just watch, i don't see any new messages at the log.
The sound just starts delaying gradually. If i check the recording later, it
has the same delay, so it looks like the delay is being recorded, not just a
problem at playing back.

Anyway, if the info helps, i can see some bad messages when changing
channels. Like these:
*----------------------------------------------------------------------*
*2010-01-22 15:23:01.711 WriteAudio: buffer underrun*
*2010-01-22 15:23:07.495 WriteAudio: buffer underrun*
*2010-01-22 15:23:07.735 NVP(0): prebuffering pause*
*----------------------------------------------------------------------*

So, when i change channels, i get these messages, the video starts showing
but the audio starts 1 or 2 seconds later, and late.
Maybe this problem is related with the gradual delay, and changing channels
just makes it stall. But again, it happens gradually too without touching
anything and without any message.

Thanks,
Sergio.



On Fri, Jan 22, 2010 at 2:27 PM, Nick Morrott <knowledgejunkie at gmail.com>wrote:

> 2010/1/22 Sergio Tashdjian <gtashi at gmail.com>:
> > Hi guys, i've been googling and reading lots of posts trying to solve
> this
> > problem, but no luck so far.
> > I have mythtv installed in Ubuntu 9.10 (Karmic Koala) using the package
> > provided in the Ubuntu repository.
> > Mythtv version there is .22
> > My problem is that audio/video sync starts ok , but sound gets delayed
> > gradually, more and more. After an hour watching tv or recording a show
> the
> > delay in sound may reach more than 5 seconds.
> > Im runing backend and frontend on the same Core 2 Duo PC with 2 GB ram.
> CPU2
> > shows high usage when watching tv, but CPU1 is almost free.
> > I don't see any video or audio jumps , nor quality problems, it looks and
> > sounds perfectly, except for the growing sync loose.
>
> What type of capture card are you using? Do you see any
> audio/video/sync messages in your mythfrontend logfile?
>
> Nick
>
> --
> Nick Morrott
>
> MythTV Official wiki: http://mythtv.org/wiki/
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>
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