[mythtv-users] "Woodchuck" sound on TV playback

[John Welch]

On Wed, Aug 13, 2008 at 10:37 PM, Allen Edwards
<allen.edwards at oldpaloalto.com> wrote:
> This is what I recommend to set up digital sound.
>
> 1) remove or rename the two alsa config files (asound.conf and .asoundrc)
> 2) some people have to uninstall pulse audio.  I think this is with Fedora.
> 3) Sound ALSA:default
> 4) Passthrough ALSA:spdif
> 5) check Stereo (not 5.1)
> 6) turn on iec958 in alsamixer
>
> chipmunks and digital noise should be gone.
>
> Allen

I'm having this same issue with the "woodchuck" or "static chatter"
sounds, as it has been described here, when trying to passthrough
sound to my HT receiver.  I was hoping that following these steps
would fix the problem, but unfortunately it did not.  I saw the
suggestion in a previous posts to turn off AC3/DTS passthrough in the
MythTV setup, and when I do this I do the get audio, but I WANT the
passthrough enabled (red light comes on on the receiver, full 5.1
sound, etc.).  I've gotten it to work on other frontends, but nothing
I've tried has been successful on this one.

One thing I'm curious about is step 6, where you say "turn on iec958
in alsamixer".  In my alsamixer settings I've got a regular volume bar
for IEC958.  I've un-muted it and pushed it all the way up to 100.
I've also got another "IEC958 Playback Source" setting, which I can
toggle through four settings: PCM, ADC1, ADC2, and ADC3.  So far in my
testing, if I set it to PCM I get the "static chatter"; if I set it to
any of the other settings I get nothing.

For reference, I'm running Fedora 9.  I've gotten the same results
regardless of whether or not I have pulse audio installed (it is
currently not installed).  I've also tried using the
.asoundrc/asound.conf file from the MythTV wiki with the same results.
 My sound card is on-board, and shows up as an HDA Intel / AD198x.

Any help would be greatly appreciated.

TIA,
John