[mythtv-users] Can't get S/PDIF sound working

[Phill Edwards]

I've just bought a S/PDIF header for my Gigabyte mobo and am having
trouble getting any sound out of it.

I've taken the Jarod's .asoundrc which in turn was taken from the
DigitalSoundHowTo at
http://www.mythtv.info/moin.cgi/DigitalSoundHowTo. Jarod said that he
only had to change 4 lines to get his working. The main thing seemed
to be getting the device number right. The output of "aplay -l" gives
me:

[elm|~]$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: I82801DBICH4 [Intel 82801DB-ICH4], device 0: Intel ICH [Intel
82801DB-ICH4]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: I82801DBICH4 [Intel 82801DB-ICH4], device 4: Intel ICH -
IEC958 [Intel 82801DB-ICH4 - IEC958]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

So I assume my S/PDIF device is number 4 - is that correct?

My .asoundrc looks like this:
### This is taken from Jarod Wilson's MythTV HOWTO which in turn 
### took it from the DigitalSoundHowTo at http://www.mythtv.info
# Override the default output used by ALSA.
# If you do not override the default, your default
# device is identical to the (unmixed) analog device
# shown below.  If you prefer mixed and/or digital
# output, uncomment the appropriate four lines below
# (only one slave.pcm line).
### Currently set w/digital-hw as the default output,
### comment out this entire section to use unmixed
### analog as your default
### -jarod
pcm.!default {
  type plug
## Uncomment the following to use mixed analog by default
#  slave.pcm "dmix-analog"
## Uncomment the following to use unmixed digital by default
  slave.pcm "digital-hw"
## Uncomment the following to use mixed digital by default
#  slave.pcm "dmix-digital"
}

# Alias for analog output on the Audigy (hw:0,0)
# - This is identical to the device named "default"--which
# always exists and refers to hw:0,0 (unless overridden)
# - Therefore, we can specify "hw:0,0", "default", or "analog"
# to access analog output on the Audigy
pcm.analog {
 type plug
 slave.pcm "analog-hw"
}

# Control device (mixer, etc.) for the Audigy card
ctl.analog {
 type hw
 card 0
}

# Alias for (rate-converted) mixed analog output on the
# Audigy (hw:0,0)
#  - This will accept audio input--regardless of rate--and
# convert to the rate required for the dmix plugin
# (in this case 48000Hz)
pcm.mixed-analog {
 type plug
 slave.pcm "dmix-analog"
}

# Control device (mixer, etc.) for the Audigy card
ctl.mixed-analog {
 type hw
 card 0
}

# Alias for (rate-converted) digital (S/PDIF) output on the
# Audigy (hw:0,0)
#  - This will accept audio input--regardless of rate--and
# convert to the rate required for the S/PDIF hardware
# (in this case 48000Hz)
pcm.digital {
 type plug
 slave.pcm "digital-hw"
}

# Control device (mixer, etc.) for the Audigy card
ctl.digital {
 type hw
 card 0
}

# Alias for mixed (rate-converted) digital (S/PDIF) output on the
# Audigy (hw:0,0)
#  - This will accept audio input--regardless of rate--and
# convert to the rate required for the S/PDIF hardware
# (in this case 48000Hz)
pcm.mixed-digital {
 type plug
 slave.pcm "dmix-digital"
}

# Control device (mixer, etc.) for the Audigy card
ctl.mixed-digital {
 type hw
 card 0
}

# The following devices are not useful by themselves.  They
# require specific rates, channels, and formats.  Therefore,
# you probably do not want to use them directly.  Instead use
# of of the devices defined above.

# Alias for analog output on the Audigy (hw:0,0)
# Do not use this directly--it requires specific rate,
# channels, and format
pcm.analog-hw {
 type hw
 card 0
 # The default value for device is 0, so no need to specify
}

# Control device (mixer, etc.) for the Audigy card
ctl.analog-hw {
 type hw
 card 0
}

# Alias for digital (S/PDIF) output on the Audigy (hw:0,0)
# Do not use this directly--it requires specific rate,
# channels, and format
pcm.digital-hw {
 type hw
 card 0
 device 4
}

# Control device (mixer, etc.) for the Audigy card
ctl.digital-hw {
 type hw
 card 0
}

# Direct software mixing plugin for analog output on
# the Audigy (hw:0,0)
# Do not use this directly--it requires specific rate,
# channels, and format
pcm.dmix-analog {
 type dmix
 ipc_key 1234
 slave {
   pcm "analog-hw"
   period_time 0
   period_size 1024
   buffer_size 4096
   rate 48000
 }
}

# Control device (mixer, etc.) for the Audigy card
ctl.dmix-analog {
 type hw
 card 0
}

# Direct software mixing plugin for digital (S/PDIF) output
# on the Audigy (hw:0,0)
# Do not use this directly--it requires specific rate,
# channels, and format
pcm.dmix-digital {
 type dmix
 ipc_key 1235
 slave {
   pcm "digital-hw"
   period_time 0
   period_size 1024
   buffer_size 4096
   rate 48000
 }
}

# Control device (mixer, etc.) for the Audigy card
ctl.dmix-digital {
 type hw
 card 0
}


My problem is that none of the lines below produce any sound output
when I connect the S/PDIF TOSLINK to my receiver:

[elm|~]$ aplay -D digital pronounce_linux.au
[elm|~]$ aplay pronounce_linux.au

If I put the old analogue connection back in from the sound card to
the receiver then I can get sound again, but I want to get this
working so I can get Dolby from MythDVD.

Does anyone know where I'm going wrong here?

Regards,
Phill