[mythtv-users] Followed Digital Sound setup, many how-to's, and still completely lost.

[Rich West]

Steven Adeff wrote:
> On 2/3/07, Rich West <Rich.West at wesmo.com> wrote:
>   
>> Rich West wrote:
>>     
>>> Steven Adeff wrote:
>>>       
>>>> On 2/3/07, Rich West <Rich.West at wesmo.com> wrote:
>>>>         
>>>>> Rich West wrote:
>>>>>           
>>>>>> *sigh*  I am reluctantly sending this to the listt, but no matter what I
>>>>>> try, I cannot seem to get consistent results from any of the "digital
>>>>>> sound" how-to's.
>>>>>>
>>>>>> Goal:
>>>>>> Pump all sound out via SPDIF and let my receiver do the work.
>>>>>>
>>>>>> Near Goal:
>>>>>> Hey, I would be content if I just had to switch the input on my receiver
>>>>>> from the TV setting (L/R stereo in)) to my DVD setting (Optical 5.1
>>>>>> Audio in).
>>>>>>
>>>>>> What I have tried so far:
>>>>>> http://www.mythtv.org/wiki/index.php/Configuring_Digital_Sound#ALSA_Utilities,
>>>>>> http://gentoo-wiki.com/HOWTO_Dolby_Digital_Out_(AC3,_SPDIF) (I have FC5,
>>>>>> but I thought some of it might apply), along with following a couple of
>>>>>> threads in the list.
>>>>>>
>>>>>> Here's where I am at:
>>>>>> <..snip..>
>>>>>> Although I've read the Wiki's, How-To's, and other postings, I just feel
>>>>>> like I am missing something simple here...
>>>>>>
>>>>>>
>>>>>>
>>>>>>             
>>>>> Muhaha.. I just got things working.  I missed the thread from "Josh
>>>>> <TwoOneSix at thatclothingco.com>" titled "Re: [mythtv-users] M-Audio
>>>>> Revolution 5.1 and FC6 [Working!]".
>>>>>
>>>>> The piece I was missing was (sort-of) listed in his message.  I needed
>>>>> to set the default audio-output to ALSA:default along with the
>>>>> passthrough device to ALSA:default.
>>>>>
>>>>> Watching LiveTV and watching recordings now outputs via the SPDIF
>>>>> optical connection (interestingly, my receiver flips to "Dolby
>>>>> Prologic"), and watching DVD Video's also outputs the sound via SPDIF
>>>>> optical and the receiver properly sees the incoming stream as AC3.
>>>>>
>>>>> Interestingly, though, MythMusic no longer outputs anything.. Gotta look
>>>>> in to that.
>>>>>
>>>>> BYW: Thanks Josh!
>>>>>
>>>>> -Rich
>>>>>
>>>>>
>>>>>           
>>>> MythMusic has a separate device option, so you just need to go into
>>>> the MythMusic settings and change it to match what you have for TV.
>>>>
>>>>         
>>> After seeing in my mythtvfrontend.log (I never even knew that there was
>>> a "-v audio" option to mythfrontend. :) ):
>>> 2007-02-03 13:42:04.346 Opening ALSA audio device 'spdif'.
>>> 2007-02-03 13:42:04.347 in SetParameters(format=2, channels=2,
>>> rate=44100, buffer_time=500000, period_time=125000)
>>> 2007-02-03 13:42:04.348 AudioOutput Error: Rate doesn't match (requested
>>> 44100Hz, got 48000Hz)
>>>
>>> And then seeing your message, I changed the output device to /dev/dsp.
>>> Muhahah.. that worked.  I just set it to /dev/dsp to use the L/R audio out.
>>>
>>> It's actually kind of interesting that the optical input on my receiver
>>> is tagged as "CD Optical Audio In".  CD's are 44.1khz, right?
>>>
>>> Too bad I can't pump everything through the optical connection.. I
>>> wonder why it won't send it at 44.1khz..
>>>       
>> Wow.. didn't realize just how close I was. :)
>>
>> I updated /etc/modprobe.conf to include:
>> options snd-pcm-oss adsp_map=1
>>
>> As per the KnoppMyth Wiki (I'm not running KnoppMyth, though), but that
>> alone did not help.  However, a little further UP in that wiki entry, I
>> came across an /etc/asound.conf entry:
>> pcm.!default {
>> type plug
>> slave {
>> pcm "spdif"
>> rate 48000
>> format S16_LE
>> }
>> }
>>
>>
>> I put that in place, updated the default output device and passthrough
>> device to be "ALSA:default" and set the MythMusic device back to "default".
>>
>> Viola!  Everything goes through the optical connection... :)
>>     
>
> Rich, I humbly ask that you create a mythtv wiki entry for your setup
> to help any of those that may be looking to use the same sound setup
> you have.
>   

There currently is a WIKI entry for Digital Sound.. I'll update it to 
reflect my experiences..

-Rich