[mythtv-users] Yet another sound problem

[Kevin Kuphal]

David Wadler wrote:

>>David Wadler wrote:
>>    
>>
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>  
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>>>I had to wipe my drive (don't ask) and am now running a 2.6.6 kernel.
>>>The new kernel made it very easy to get ALSA up-and-running and I'm
>>>using it in Xine, mplayer, XMMS, and other apps.  However, when I set
>>>Myth to use ALSA:default, I got choppy video (lots of prebuffering
>>>messages) and audio that wasn't quite right.  It sounds clipped.  I
>>>played with the mixer levels, and no matter how low I go, there
>>>remains distortion.  I switched to /dev/dsp and /dev/adsp, both of
>>>which work, but both of which have the same audio distortion.  In
>>>addition to adjusting the levels with my soundcard, I also tried to
>>>adjust the TV-Card's mixer, by doing alsamixer -c 1.  I can only
>>>adjust the level attached to "Capture" and changing it doesn't have
>>>any effect.
>>>      
>>>
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>Kevin, thanks for the response.  Let me go address the things you brought up
>one-by-one:
>
>1)  Audio hardware:  Multimedia audio controller: VIA Technologies, Inc.
>VT8233/A/8235/8237 AC97 Audio Controller  (It's pretty generic, onboard
>audio, but is more than adequate for my needs and has a fairly large
>userbase.)
>
>2)  Yes, I have the audio from my capture card going to the line-in on my
>soundcard.
>  
>
Ok.  In this case then all your sound should be related to your VIA 
technologies card.  You should be able to set Capture on the Line In in 
the alsamixer and turn up the Capture "volume" and Line-In volume.  Out 
of curiosity, are those turned all the way up or only partially.  I 
believe on mine if I set the Capture level/gain above 60 that I would 
get distortion.  I have a different sound system but maybe it holds true.

>3)  I never explicitly load tvaudio; it seems to load when bttv does.  In
>any case, it doesn't seem to do anything.  I get not-very-good sound
>regardless of whether the module is loaded or not.
>  
>
You might try rmmod-ing the unnecessary modules.  Can you post your 
/etc/modules.conf and maybe we can see if it is being loaded somewhere.  
Perhaps too many cooks in the kitchen :)

>4)  I've been playing with the ALSA bt87x driver.  Loading it creates
>/dev/dsp1.  However, MythTV reports "No such device" when I try to assign
>sound to it.  I've just been running modprobe to load it; are there
>configuration options I'm missing?  Right now, it doesn't seem to do
>anything...apparently a recurring theme with my tv-related sound modules.
>  
>
It probably isn't necessary if you are able to get sound through your 
line in.  Although it might be a fallback if you continue to have 
trouble.  I'd leave it alone for now.

Kevin