Re: [Alsa-user] Pass through problem

[Alan B. <ab...@ve...>]

Lee Revell wrote:
 > On Mon, Feb 23, 2009 at 8:09 AM, Alan Bromborsky 
<ab...@ve...> wrote:
 >  
 >> System: Asus M3N78 PRO (On board sound disabled)
 >> Sound Card: C-Media CMI8738 (Using ALSA mixer)
 >> OS: Ubuntu 8.10 amd64 (Upgraded 2/22/09)
 >>
 >> Problem: Using line-in on sound card to capture sound from verizon
 >> set-top-box.  Sound is passed through to sound output (speakers) unless
 >> I mute line-in on alsa mixer
 >>     
 >
 > All the time, or only if tvtime is running?
 >
 >  
 >> but if I mute line-in I cannot capture
 >> sound under any circumstances.  I wish sound output to happen only if
 >> application I am running requests it (tvtime for example).  How do I set
 >> up sound system to accomplish this?
 >>
 >>     
 >
 > This is a job of the app, not ALSA.
 >
 > Please post the output of "amixer".
 >
 > Lee
 >
 >   
Attached is the output of amixer.  The line-in is passed to the speaker 
even if tvtime or anyother sound app is running or not.  If I try to run 
vlc I get a feedback effect in the sound coming out of the speakers.  
There are no microphones on my system so any feedback would have to be 
internal.

Output of amixer:

Simple mixer control 'Master',0
  Capabilities: pvolume
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono:
  Front Left: Playback 31 [100%]
  Front Right: Playback 31 [100%]
Simple mixer control '3D Control - Switch',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'PCM',0
  Capabilities: pvolume pswitch pswitch-joined cswitch
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Front Left: Playback 31 [100%] [on] Capture [on]
  Front Right: Playback 31 [100%] [on] Capture [on]
Simple mixer control 'Synth',0
  Capabilities: pvolume pswitch pswitch-joined cswitch
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Front Left: Playback 25 [81%] [on] Capture [off]
  Front Right: Playback 25 [81%] [on] Capture [off]
Simple mixer control 'Line',0
  Capabilities: pvolume pswitch cswitch
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Front Left: Playback 31 [100%] [on] Capture [on]
  Front Right: Playback 31 [100%] [on] Capture [on]
Simple mixer control 'Line-In Mode',0
  Capabilities: enum
  Items: 'Line-In' 'Rear Output' 'Bass Output'
  Item0: 'Line-In'
Simple mixer control 'CD',0
  Capabilities: pvolume pswitch cswitch
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Front Left: Playback 31 [100%] [on] Capture [on]
  Front Right: Playback 31 [100%] [on] Capture [on]
Simple mixer control 'Mic',0
  Capabilities: pvolume pvolume-joined cvolume cvolume-joined pswitch 
pswitch-joined cswitch cswitch-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: Playback 0 - 31 Capture 0 - 7
  Mono: Playback 0 [0%] [off] Capture 0 [0%] [off]
Simple mixer control 'Mic Boost',0
  Capabilities: pswitch pswitch-joined cswitch cswitch-joined
  Playback channels: Mono
  Capture channels: Mono
  Mono: Playback [off] Capture [off]
Simple mixer control 'Mic-In Mode',0
  Capabilities: enum
  Items: 'Mic-In' 'Center/LFE Output'
  Item0: 'Center/LFE Output'
Simple mixer control 'Phone',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined
  Playback channels: Mono
  Limits: Playback 0 - 7
  Mono: Playback 0 [0%] [off]
Simple mixer control 'IEC958 5V',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [on]
Simple mixer control 'IEC958 Copyright',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'IEC958 In Monitor',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'IEC958 In Phase Inverse',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'IEC958 In Select',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'IEC958 In Valid',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'IEC958 Loop',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'IEC958 Output',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'PC Speaker',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined
  Playback channels: Mono
  Limits: Playback 0 - 3
  Mono: Playback 2 [67%] [on]
Simple mixer control 'Aux',0
  Capabilities: pvolume pswitch cswitch
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: Playback 0 - 15
  Front Left: Playback 15 [100%] [on] Capture [on]
  Front Right: Playback 15 [100%] [on] Capture [on]
Simple mixer control 'Four Channel Mode',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [on]