[mythtv-users] S/PDIF sound problems for PVR350 - a solution

[Gerald Schepens]

I wonder if there's any easy way to get mythtv to parse out the audio 
from the .nuv file on a recording playback and send it to the alsa out.  
Presumably, the .nuv file format is not exactly what the 350 uses, so 
some preprocessing must be taking place?  Not that it's a huge deal but 
it'd be nice to be able to switch between the pvr and, say, a video card 
output without rewiring stuff.

David wrote:

> Sorted :)
>
> running:
> arecord -D hw:0,0 -fdat | aplay -D mixed-digital
>
> Whilst Myth's playing works a treat...
> (mixed-digital is my alsa device name)
>
> Not checked sound quality etc yet but it's there.
> Maybe myth could start a thread to do this on playback?
>
> David
>
> David wrote:
>
>> The sound does come from the PVR - but then it comes back in through the
>> line in and from here I  thought Myth sent it out through the PCM audio
>> device with volume control.
>>
>> The FAQ, section 7.2 sugegsts
>>  amixer set Line,0 75%,75% mute captur
>> which sets lin-in to 75%, mute's it and marks it for capture
>> then
>>  amixer set Capture,0 100%,100% mute captur
>> I interpret as mute the capture channel (so it's not heard directly),
>> listen to the capture intput (line-in) at 100% and act as a capture
>> device (so Myth can read it)
>>
>> So I want to make the pcm go through the S/PDIF - which works for 
>> Mythmusic.
>>
>> OK, further reading suggests that Myth doesn't do this for the PVRs - 
>> maybe I can run  something in parallel that captures line-in and 
>> feeds it to the pcm output.
>>
>> David
>>
>>
>> James Satterfield wrote:
>>
>>> It's my understanding that if you're using pvr350 out, the audio 
>>> only comes from the pvr. AFAIK, what you want cannot be done.
>>>
>>> James.
>>>
>>>
>>> David <myth at dgreaves.com> wrote: 
>>>
>>>> I'm trying to get s/pdif to work with myth.
>>>> I'm using an onboard Via8233
>>>>
>>>> It works fine with mplayer but not myth.
>>>> Myth is built with alsa support - I've currently (temporarily) 
>>>> disabled oss-emulation in the kernel too.
>>>>
>>>> I've used ALSA:mixed-digital (from Michael Dean's config) and it 
>>>> works very nicely with mplayer
>>>> mplayer -ao alsa1x:mixed-digital my.mp3
>>>> gives nice clear properly timed s/pdif output.
>>>>
>>>> I'm using a PVR350 and I feed the audio output back into the 
>>>> soundcard's line in.
>>>> Now I expected myth to be listening to the line in (marked as 
>>>> capture in alsamixer) and outputting it via pcm to the spdif.
>>>> But it's not.
>>>>
>>>> Instead I can only hear myths output when I unmute the line-in - 
>>>> and of course then I'm getting analog playback.
>>>>
>>>> It seems like Myth is only generating sound via the PVR and isn't 
>>>> then playing back line-in (at which point I would need to mute 
>>>> line-in to avoid 'echo')
>>>>
>>>> Any suggestions?
>>>>
>>>> David
>>>> _______________________________________________
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>>>> mythtv-users at mythtv.org
>>>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>>>>
>>>>   
>>>
>>>
>>>
>>>
>>>  
>>>
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>>
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