[mythtv-users] Lost audio on Pundit SPDIF audio out.

[Jarod C. Wilson]

On Friday, Oct 24, 2003, at 22:36 US/Pacific, Gary Raposo wrote:

> I'm about ready to give up here so I thought I'd shoot my situation 
> out over the list to see if anyone else has experienced this.  Had 
> MythTV v.011 up and running and all was great!  Then all of a 
> sudden... no sound!  The system was "in production" so it's not like I 
> was tinkering with it at the time so this was a little bit of a shock.

Ah, but you were indeed tinkering. You just installed a new version of 
ALSA.

> I've got the SPDIF out from the front of the Pundit connected to my 
> home theatre receiver.  The receiver has been detecting the PCM stereo 
> stream up until now and has had no problems decoding it.  Now it's as 
> if the receiver does not see the optical input (autodetect does not 
> work and forcing the receiver to optical does not work either).
>
> I can see the red light coming from the SPDIF out port so I know that 
> something is happening on the Pundit side.  I've tested the receiver 
> input port and cable using a known good cable and my DVD player.  I 
> went through all the permutations and isolated it down to the Pundit.  
> Now... I'm not sure if this is a hardware problem or a software 
> problem.

Software problem.

> I checked alsamixer and the settings were unchanged (unmuted master, 
> master m, and PCM).  The interesting thing is that if I plug in some 
> headphones or computer speakers I can hear the audio so it really 
> seems like it's not a hardware problem.

They're changed. But only very slightly. I had something similar happen 
when I bumped up from 0.9.7 with my Audigy. Everything looked the same 
in the settings, but the digital output was disabled. Look in alsamixer 
for a digital output setting toward the far right. I betcha it is set 
to mute/off.

> My question is... does ALSA have some control over directing audio out 
> over the SPDIF interface or is the SPDIF just a slave managed bu the 
> hardware that mirrors the audio to all available outbound ports on the 
> box?

ALSA controls whether the SPDIF interface is active or not.

> Any help would be greatly appreciated.  I've looked through the list 
> archived and googled around but I can't find anyone that's using the 
> optical out on the Pundit that's having the same problem.  I'd like to 
> stay with the optical audio since my next mini-project will be to 
> install a DVD player so having the digital 5.1 sound would be nice.  
> Maybe I have a bad SPDIF out port on the Pundit?  Who knows?  
> Hopefully, it's just a software setting that I have to change.

I have a feeling you just need to turn the digital output back on, and 
all should be well. I believe this is a recent change in ALSA, because 
previous ALSA updates didn't do quite the same for me (it often liked 
to re-mute everything, rather than just disabled digital out).

--Jarod

-- 
Jarod C. Wilson, RHCE

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