[mythtv-users] All sound out S/PDIF (was: Dolby Digital Signal indicator on Receiver)

[Mark Knecht]

On Sun, May 18, 2008 at 8:01 AM, David Snider <dsnider at thesniderpad.com> wrote:
> Michael T. Dean wrote:
>> On 05/18/2008 02:14 AM, Bob Sully wrote:
>>
>>> Still no luck with getting stereo streams to play in mythfrontend (using
>>> the internal player for recordings, or mythmusic) if a file with Dolby
>>> Digital 5.1 sound is played first.
>>>
>>> I can play any videos, no matter what the sound codec is, within myth with
>>> this: "mplayer -fs -zoom -quiet -vo xv -ao alsa:device=spdif -afm hwac3
>>> %s").
>>>
>>> Right now, I still have to exit mythfrontend and run "iecset audio 0",
>>> then restart the frontend to play a stereo recording if I have watched a
>>> 5.1 show before it.
>>>
>>
>> That's due to a misconfiguration of your audio system.
>>
>>
>>>   This is the case with my combined BE/FE machine (uses
>>> an Asus P5K-Deluxe/Wifi motherboard) and my upstairs frontend (ABit
>>> AN8-32X).  I do not have to do this if I play only recordings with DD 5.1
>>> audio.
>>>
>>> The previously mentioned work-around with a remote would be an interim
>>> fix, if I used a remote (I don't; I use RF keyboards on both machines).
>>>
>>> Has anyone yet found a fix for this within mythfrontend, so that the
>>> internal player for recordings and music will allow ALL sound to go out
>>> via the S/PDIF interface?
>>>
>>>
>>
>> It has nothing to do with Myth.  It's completely an audio configuration
>> issue.
>>
>>
>>> If not...this is a feature request (or is it a bug-fix request? - not
>>> sure).  ;-)
>>>
>>
>> System configuration bug.  :)
>>
>> Mike
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>> mythtv-users at mythtv.org
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>>
> I recently just ran into this exact same issue.  I don't know why, but
> after I upgraded to .21, (and alsa, and my kernel, and a bunch of stuff)
> only the digital passthrough stuff worked.  I'm on gentoo and found a
> file named /etc/asound.names.  In it I found device names that I didn't
> see through the typical aplay -L.   One was named plug:spdif.  After
> going through line by line on the names running aplay -D <name>
> /usr/share/sounds/alsa/Noise.wav (an analog file).  I finally heard
> sound when I used plug:spdif.  So, in MythFrontend, I changed the
> default alsa device from ALSA:default to ALSA:plug:spdif and now
> everything works perfectly.
>

David,
   I'd like to know more about this. I've been around alsa a long time
and I've never heard of /etc/asound.names. I'm also a Gentoo user and
none of my machines (8 in total) have this file so it being on your
system is a surprise to me. I know of /etc/asound.state. Did you
possibly mean that file?

   I think the intended method to get a list of devices or PCMs is to
use aplay -l or aplay -L

mark at lightning ~ $ aplay -lL
default:CARD=CK804
    NVidia CK804, NVidia CK804
    Default Audio Device
front:CARD=CK804,DEV=0
    NVidia CK804, NVidia CK804
    Front speakers
surround40:CARD=CK804,DEV=0
    NVidia CK804, NVidia CK804
    4.0 Surround output to Front and Rear speakers
surround41:CARD=CK804,DEV=0
    NVidia CK804, NVidia CK804
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=CK804,DEV=0
    NVidia CK804, NVidia CK804
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=CK804,DEV=0
    NVidia CK804, NVidia CK804
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
null
    Discard all samples (playback) or generate zero samples (capture)
default:CARD=DSP
    Hammerfall DSP, RME Hammerfall HDSP 9652
    Default Audio Device
**** List of PLAYBACK Hardware Devices ****
card 0: CK804 [NVidia CK804], device 0: Intel ICH [NVidia CK804]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: CK804 [NVidia CK804], device 2: Intel ICH - IEC958 [NVidia
CK804 - IEC958]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: DSP [Hammerfall DSP], device 0: RME Hammerfall HDSP 9652 [RME
Hammerfall HDSP 9652]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
mark at lightning ~ $

However this doesn't show that my system has any PCMs so I'm very
curious as to how we are getting different results. Have you set up a
virtual device under Alsa and you're getting something that way?

Thanks,
Mark