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

[Steven Adeff]

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, 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

matt, mail it to me off-list and I'll check it for you.

--
Steve