[mythtv-users] Not getting Dolby Prologic out of s/pdif

[Matt]

On 3/15/06, Steven Adeff <adeffs.mythtv at gmail.com> wrote:
> On 3/15/06, Matt <skd5aner at gmail.com> wrote:
> > On 3/15/06, Steven Adeff <adeffs.mythtv at gmail.com> wrote:
> > > On 3/15/06, Matt <skd5aner at gmail.com> wrote:
> > > > On 3/15/06, Steve Skarda <steveskarda at gmail.com> wrote:
> > > > > Make sure you have use video as timebase turned off in the playback
> > > > > settings.   Having it checked will allow digital signals to work but AC3
> > > > > passthrough won't.   Not sure if that is related to your problem or not.
> > > >
> > > > It is turned off.
> > > >
> > > > Let me just try to quickly sum up my issue:
> > > >
> > > > 1) I receive HDTV OTA ATSC signal via HD5000
> > > > 2) The first audio track says it's AC3 5.1
> > > > 3) Receiver set to "AFD" - Auto Format Decode
> > > > 4) When it receives the signal, the LCD on the receiver doesn't do
> > > > anything (doesn't say what kind of signal it is receiving" and I can
> > > > hear noice out of my left and right channels, but never the full
> > > > signal (missing voices, etc).
> > > > 5) If I switch the receiver to "Normal Surround" I'll get the
> > > > channels, but the receiver NEVER says it's decoding AC3.
> > > > 6) If I play a Standard Def recording from my PVR250/500, the receiver
> > > > will get the signal and say it's playing a PCM signal.
> > > >
> > > > I think I'm going to submit a ticket, but before I do that, what else
> > > > should I do/try/troubleshoot?
> > > >
> > > > Thanks!
> > > > Matt
> > >
> > > sounds like you don't have ALSA set up to pass AC3 signals, thus they
> > > are being sent as stereo pcm. search the list/wiki and you should find
> > > information on how to enable AC3 using .asoundrc
> > >
> >
> > Correct me if I'm wrong, but I believe I do.  Here's my .asoundrc:
> >
> > 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"
> > }
>
> Here's my asoundrc file, as well I have "ALSA:digital" for my audio
> output device in MythTV...
>
> # 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"
> # slave.pcm "digital-hw"
> ## Uncomment the following to use mixed digital by default
> # slave.pcm "dmix-digital"
> }
>
> # Alias for analog output on the nForce2 (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
> 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 (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 card
> ctl.analog-hw {
>  type hw
>  card 0
> }
>
> # Alias for digital (S/PDIF) output on the nForce2 (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 card
> ctl.digital-hw {
>  type hw
>  card 0
> }
>
> # Direct software mixing plugin for analog output on
> # the nForce2 (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 card
> ctl.dmix-analog {
>  type hw
>  card 0
> }
>
> # Direct software mixing plugin for digital (S/PDIF) output
> # on the nForce2 (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 card
> ctl.dmix-digital {
>  type hw
>  card 0
> }
>
> --
> Steve

I copied and pasted as is, and it didn't make any difference.  I still
think the AC3 track that is being "passed through" is bogus in some
fashion.  I'm more than happy to send the recording to someone for
them to play with.  In fact, I can record a short 5 mins of any HD
track with AC3 5.1 and send it so it's not so big.  Anyone interested?

Matt