[mythtv-users] Still no AC3 passthrough...

[Greg Arena]

Ryan,

	Yes, I copied & pasted the .asoundrc from the
"Configuring Digital Sound" wiki on mythtv.org. I put in both
sections of the file shown there (there's an add-on section below
it that the page says is for "simulatenous digital and analog
output"). When I do that and change "Audio output device" to
"ALSA:multi" and passthrough device to "ALSA:digital" or
"ALSA:mixed-digitial" like it says, I get no sound at all - even
if I go and shut off the AC3 passthrough. The only way to get any
audio back is either to delete the .asoundrc file or comment out
the add-on section that I mentioned above and change the Audio
output device back to "ALSA:default".
	Running aplay -l returns:

[root at arenamedia ~]# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: CMI8738MC6 [C-Media PCI CMI8738-MC6], device 0:
CMI8738-MC6 [C-Media PCI DAC/ADC]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: CMI8738MC6 [C-Media PCI CMI8738-MC6], device 1:
CMI8738-MC6 [C-Media PCI 2nd DAC]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: CMI8738MC6 [C-Media PCI CMI8738-MC6], device 2:
CMI8738-MC6 [C-Media PCI IEC958]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

	Running aplay -L gives me a segmentation fault. Despite
this, I went ahead and modified the .asoundrc file to use device
2 for the "pcm.digital-hw" entry anyway since that appears to be
the right one. But like I said, when I try to use that, I get
nothing.
	I used yum to install MythTV using the "mythtv-suite"
meta-package rather than attempting to compile it along with
downloading other dependencies where needed. Running "rpm -q
mythtv" returns "mythtv-0.20.1-157.el5".
	That seg fault started when I tried to get this going
with the Audigy 4 before I found out it would never work, and it
has me wondering if I screwed something else up in the process.
Since I have some unpartitioned space available on my hard drive,
I'm downloading MythDora to see if maybe I can start with a
combination of packages that are known to get along together.
It's taking a long time, though. Regardless, I don't want to give
up on this yet incase MythDora fails to install or ends up giving
me the same trouble.

Thank you,
Greg

-----Original Message-----
From: mythtv-users-bounces at mythtv.org
[mailto:mythtv-users-bounces at mythtv.org] On Behalf Of Ryan
Steffes
Sent: Friday, October 12, 2007 3:50 PM
To: Discussion about mythtv
Subject: Re: [mythtv-users] Still no AC3 passthrough...

On 10/12/07, Greg Arena <garena6 at comcast.net> wrote:
>         I posted yesterday with problems getting the AC3
> passthrough to work. I was told that the driver for the SB
Audigy
> 4 I had bought didn't support this. So after switching from the
> SB Audigy 4 to a Turtle Beach Riviera card which I was told had
> full support for this, I'm still stuck with the same problem:
No
> AC3 passthrough. Audio works fine for 2-channel output through
> the SPDIF optical out for SD and HD broadcasts if I shut off
AC3
> passthrough in the setup. But otherwise, I still get silence or
> static when I turn it on.
>         Can somebody out there with a Turtle Beach Riviera (or
> anybody using the snd_cmipci ALSA driver) offer any ideas? Or,
> can you please send me your ALSA config files and tell me how
you
> have things set up in the "Audio" section of the front end's
> general setup screen?
>         As I said before, I've gone through all the howto's and
> wiki's I can find, and none has been helpful.
>
> Thank you,
> Greg
>

Well, I don't have your particular card, and while I set up the
.asoundrc according to the wiki, it was a bit of a struggle.
However,
that aside, maybe I can still guide you into some responses that
elicit more help from someone more knowledgeable.

Are you using the .asoundrc from the wiki?  If so, have you made
sure
the device numbers match up to what your system tells you it
should?
My uneducated guess at what's happening is that your non-digital
sound
is being sampled correctly for your soundcard, but your digital
sound
is being played at the wrong sample rate and needs to be sampled
with
.asoundrc

What does aplay -l -L report?

Are you using SVN?  Does the version of the mythfrontend you're
using
allow for a seperate sound device for AC3 passthrough (I'm not
sure
when that went in). Which sound device do you have set for sound?
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