[mythtv-users] No sound watching TV

[Alan Calvert]

Paulo Cavalcanti wrote:
> 
> 
> On 5/6/07, *Nick Morrott* <knowledgejunkie at gmail.com 
> <mailto:knowledgejunkie at gmail.com>> wrote:
> 
>     On 07/05/07, Paulo Cavalcanti <promac at gmail.com
>     <mailto:promac at gmail.com>> wrote:
>      > On 5/6/07, Nick Morrott <knowledgejunkie at gmail.com
>     <mailto:knowledgejunkie at gmail.com>> wrote:
>      > > What audio device have you specified in mythtvsetup for your
>      > > framegrabber capture card?
>      >
>      >
>      > The audio device is the default: /dev/dsp
> 
>     Do you have ALSA's OSS emulation modules loaded for your sound card, 
> 
> 
> Yes.
>  
> 
>     and have Line-In set for capture (at a suitable level) and muted? 
> 
> 
> The only thing I can set is the input source to line. But the sound does 
> not go
> to the pcm channel because alsa driver is not doing that for my card yet.
> I have to use the workaround via arecord + aplay.
> 
> amixer -c 0 sset 'Input Source' 'Line'
> amixer -c 0 cset iface=MIXER,name='ADCMux Capture Switch' 'On'
> amixer -c 0 cset iface=MIXER,name='InMux Capture Volume' 0
> amixer -c 0 cset iface=MIXER,name='InVol Capture Volume' 0
> 
>     You
>     do not want to hear the 'live' audio from the capture card when
>     watching LiveTV, but the captured and encoded audio recorded by MythTV
>     which is then played from MythTV via your PCM output. You should not
>     hear any audio directly from Line-In.
> 
> 
> 
> I understand that. There would be a delay. On another computer I have to 
> set the line in channel
> to zero for not hearing both: live plus recorded sound
> 
> But with this onboard sound card I have none of them.
> The card is not bad, just alsa is not read for it yet.
> 
> How can I do myth get the sound from arecord?
> arecord or sox seems to be the only way of getting anything from line in.
> 
> Is it possible?

Yes it is, and you really shouldn't need the arecord/sox nonsense. I'm using an
onboard hda device and it works just fine. I don't think you've mentioned what
capture card you're using, but it appears your myth sound is coming in on Line
In. When you set up the capture card in mythtv-setup, you'll only see the
/dev/dsp* options listed. However, you can (and should!) clear the field and
type in 'ALSA:default'. Then in mythtv general setup, you set the output device
as 'ALSA:default'. That's it for the myth setup.

Getting sound working now depends on getting the alsa settings on the sound
card right, and alsamixer is a good way to do that. In alsamixer, press F3 to
show the playback controls. As Nick indicated, you want Line In up (eg 80 or so),
set to capture (press <space>), and muted (press <m>). I think you'll need PCM
around 80. Then press F4 to see the Capture items. Set Capture up around 80. 
And when that doesn't quite work, experiment with the settings, keeping in mind
Nick's general guidance. It's easiest if you can do that while mythtv is running.
When (if?) you eventually get the magic combination right, save it with
'alsactl store', and write your settings down somewhere.

cheers, Cal

standard disclaimer, do not attempt these stunts at home.