Change default of using alsa mute switch to "no" for compatability with other audio players.

audio_alsa.c

@@ -162,7 +162,7 @@ static int init(int argc, char **argv) {
   // set up default values first
   set_period_size_request = 0;
   set_buffer_size_request = 0;
-  config.alsa_use_playback_switch_for_mute = 1;
+  config.alsa_use_playback_switch_for_mute = 0; // don't use it by default
 
   config.audio_backend_latency_offset = 0;
   config.audio_backend_buffer_desired_length = 0.15;

scripts/shairport-sync.conf

@@ -110,7 +110,7 @@ alsa =
 //  period_size = <number>; // Use this optional advanced setting to set the alsa period size near to this value
 //  buffer_size = <number>; // Use this optional advanced setting to set the alsa buffer size near to this value
 //  use_mmap_if_available = "yes"; // Use this optional advanced setting to control whether MMAP-based output is used to communicate  with the DAC. Default is "yes"
-//  mute_using_playback_switch = "yes"; // Use this optional advanced setting to control whether the snd_mixer_selem_set_playback_switch_all call can be used for muting. Default is yes.
+//  mute_using_playback_switch = "no"; // Use this optional advanced setting to control whether the snd_mixer_selem_set_playback_switch_all call can be used for muting. Default is "no", for compatibility with other audio players.
 };
 
 // Parameters for the "sndio" audio back end. All are optional.

shairport.c

@@ -994,6 +994,9 @@ int main(int argc, char **argv) {
     endianness = SS_BIG_ENDIAN;
   else
     die("Can not recognise the endianness of the processor.");
+    
+  // set non-zero / non-NULL default values here
+  // but note that audio back ends also have a chance to set defaults
 
   strcpy(configuration_file_path, SYSCONFDIR);
   // strcat(configuration_file_path, "/shairport-sync"); // thinking about adding a special