#setup a shell thru IPC to carry out different  
# mixer and v4l2 control commands 
my $pidcon = open3(\*CON,0,0,'/bin/sh');


# then later use it like this
&mic_con(1); #turn on Mic 

sub mic_con{
  my $con = shift;

  if($con == 1){  #turn Mic on to max for recording 
    #turn off playback to avoid feedback squeal 
    print CON "amixer cset name='AC97 Playback Volume', 0\n";
    #switch the capture to Mic 
    print CON "amixer sset Mic Capture cap\n";
    #turn up maximum Mic gain 
    print CON "amixer cset name='Mic Playback Volume', 100\n";
    #turn on Mic +20db boost 
    print CON "amixer cset name='Mic Boost (+20dB)', 1\n";
  }

  if($con == 0){  #restore old Line settings 
    #turn off Mic by changing capture to Line 
    print CON "amixer sset Line Capture cap\n";
    #turn off Mic +20db boost 
    print CON "amixer cset name='Mic Boost (+20dB)', 0\n";
    #restore normal capture volume     
    print CON "amixer cset name='AC97 Playback Volume', 88\n";
  }
}