[mythtv] Separating CAPTUR and Capture in OSS

Tom Panning tpanning at vt.edu
Tue Mar 4 12:18:22 EST 2003

When I try to watch live TV with MythTV, I hear both the sound for the live 
feed (what Myth is recording) and what's being played from the buffer. Here's 
what I'm using:
* SB Live sound card (with OSS sound drivers)
* Hauppage WinTV card
* CVS version (today) of MythTv
* Debian unstable

I know that the Faq and the How-to mention this problem, but in both documents 
the solution appears to be specific to alsa drivers. I understand what has to 
be done with the mixer in order to get it to work, but I can't seem mute the 
"CAPTUR source" without muting the "Capture mixer" (as they are referred to 
in section 17.11 of the HOWTO).

After futzing with the mixer quite a bit, here's what I've been able to 
1) There are 13 mixer controls: Volume, Pcm, Speaker, Line*, Microphone*, CD*, 
IGain*, OGain, Line1*, Digital1, PhoneIn*, PhoneOut, and Video*. (an asterisk 
(*) means that I can record this channel)

2) When I listen to mp3's using xmms, all of the controls can be muted except 
for Pcm and OGain; I can set any channel to be the recording channel and it 
does not affect playback. Moving the volume control in xmms moves the Pcm 
slider. (I have no idea why I can muting the Volume control has no effect).

3) When I use xawtv, all of the controls can be muted except for IGain and 
OGain; Line must be set to record (but the mute and volume setting have no 

4) In MythTV, if I use the xawtv settings (see #3), then I hear the live feed 
and not the playback. If I unmute the Pcm control, then I hear both the live 
feed and the playback. If I then mute the IGain control (or turn it's volume 
down to zero) then I hear just the playback for a few seconds until I hit the 
point where IGain was muted, and then there is no sound.

Can anyone tell me what's going on here?

More information about the mythtv-dev mailing list