[mythtv-users] SPDIF mutes after about an hour

Nick Morrott knowledgejunkie at gmail.com
Wed Aug 27 06:24:21 UTC 2008


On 27/08/2008, Dive Turkey <diveturkey at gmail.com> wrote:
> On Wed, Aug 27, 2008 at 12:28 AM, Nick Morrott <knowledgejunkie at gmail.com>
> wrote:
>
> >
> > On 27/08/2008, Dive Turkey <diveturkey at gmail.com> wrote:
> > > The SPDIF audio from my FE will mute itself at a predictable interval
> > > (slightly more than an hour).
> >
> > Does it happen after 1hr 11mins?
> >
> > What sound card/ALSA modules are you using?
> >
> >
>
> 1:11 seems about right.
>
>  The sound card is a Chaintech AV-710.
>
>  $ modprobe -l |grep alsa
> /lib/modules/2.6.24.4-64.fc8/kernel/drivers/media/video/saa7134/saa7134-alsa.ko
> /lib/modules/2.6.24.4-64.fc8/kernel/drivers/media/video/cx88/cx88-alsa.ko

Although I can't give you an outright Scully solution and this is more
of a Mulder hunch, it might make it easier to find the problem.

The driver internals could be using an unsigned 32-bit counter for
microseconds, giving 2^32 or 4,294,967,296 discrete counter values.
This equates to approx 4,300 seconds, or approx 1hr 11 minutes. My
interest was piqued because you can also see such 1hr 11 min issues
when capturing video under certain circumstances.

When the counter wraps back to zero, I'm guessing the SPDIF is muted.

If no-one else can help, and if you can find them, consider postings
to the ALSA users list.

Nick
(Apologies for the cult TV references, it's early :) )

-- 
Nick Morrott

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