[mythtv-users] AC3 Passthrough issues

[Matt]

Hello,

  I've been searching around, and I can't quite find someone having
the same issue I'm having.  I've got alsa with SPDIF passthrough. 
It's been working great for analog shows, and I just installed my
digital cards this weekend.  I recorded an HD broadcast today, Nascar,
and when I started to play it, all I heard was the cars.  I didn't
hear announcers, sound effects... nothing besides "VROOOOM".  So... I
figured... interesting.

I went into the menu and saw that the first audio channel said AC3
5.1.  So, I figured "This is only playing a few of the channels". 
However, it happens on all the HD stations.  I've tried many of the
suggestions I found for passthrough, but none of them worked.  I'd
either get no sound, or the same sound.

The interesting thing is, that when I played analog, my receiver would
show "PCM 48K" and play just fine.  When I played the digital, nothing
showed up on the receiver screen and it just played the sounds.  When
commercials came up, you could hear a little more, but you could tell
much was missing.

Any clues?

Here's my .asoundrc file:

# 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).
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"
}
#slave {
#pcm "spdif"
#rate 48000
#format S16_LE
#}
#}
# Alias for analog output on the nForce2/4 (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 nForce2/4
pcm.analog {
 type plug
 slave.pcm "analog-hw"
}

# Control device (mixer, etc.) for the nForce2 card
ctl.analog {
 type hw
 card 0
}

# Alias for (rate-converted) mixed analog output on the
# nForce2 (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 nForce2 card
ctl.mixed-analog {
 type hw
 card 0
}

# Alias for (rate-converted) digital (S/PDIF) output on the
# nForce2 (hw:0,2)
#  - 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 nForce2 card
ctl.digital {
 type hw
 card 0
}

# Alias for mixed (rate-converted) digital (S/PDIF) output on the
# nForce2/4 (hw:0,2)
#  - 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 nForce2 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 nForce2 (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 nForce2/4 card
ctl.analog-hw {
 type hw
 card 0
}

# Alias for digital (S/PDIF) output on the nForce2/4 (hw:0,2)
# Do not use this directly--it requires specific rate,
# channels, and format
pcm.digital-hw {
 type hw
 card 0
 device 2
}
# Control device (mixer, etc.) for the nForce2/4 card
ctl.digital-hw {
 type hw
 card 0
}

# Direct software mixing plugin for analog output on
# the nForce2/4 (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 nForce2/4 card
ctl.dmix-analog {
  type hw
 card 0
}

# Direct software mixing plugin for digital (S/PDIF) output
# on the nForce2/4 (hw:0,2)
# 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 nForce2/4 card
ctl.dmix-digital {
 type hw
 card 0
}

Thanks!
Matt