Add sample and default settings for the back ends and update documentation a little.

scripts/shairport-sync.conf

@@ -1,22 +1,23 @@
 // Sample Configuration File for Shairport Sync
-// Commented out settings are generally the defaults.
+// Commented out settings are generally the defaults, except where noted.
 
 // General Settings
 general =
 {
 //	name = "Shairport Sync Player"; // This is the name the service will advertise to iTunes. The default is "Shairport Sync on <hostname>"
 //	mdns_backend = "avahi"; // not used, not tested
-//	output_backend = "alsa"; // setting is not used, alsa is default
+//	output_backend = "alsa"; // alsa is default, other possibilities are "stdout", "pulse", "dummy". Only alsa supports synchronisation.
 //	port = 5000;
 //	password = "secret"; // default is no password
 //	interpolation = "basic"; // aka "stuffing". Default is "basic", alternative is "soxr"
 //	statistics = "no"; // print statistics in the log
 //	drift = 88; // allow this number of frames of drift before correcting it
 //	resync_threshold = 2205; // a synchronisation error greater than this will cause resynchronisation; 0 disables it
-//	log_verbosity = 0; // "0" means no verbosity, "3" is highest.
+//	log_verbosity = 0; // "0" means no verbosity, "3" is most verbose.
 //  ignore_volume_control = "no"; // set this to "yes" if you want the volume to be at 100% no matter what the source's volume control is set to.
 };
 
+// Latencies for different sources.
 latencies =
 {
 //	default = 88200;
@@ -25,6 +26,8 @@ latencies =
 //	forkedDaapd = 99400;
 };
 
+
+// How to deal with metadata, including artwork
 metadata =
 {
 //	enabled = "no";
@@ -32,6 +35,7 @@ metadata =
 //	pipe_name = "/tmp/shairport-sync-metadata";
 };
 
+// Advanced parameters for controlling how a Shairport Sync runs
 sessioncontrol = 
 {
 //	run_this_before_play_begins = "/path/to/application and args";
@@ -41,8 +45,11 @@ sessioncontrol =
 //	session_timeout = 120;
 };
 
-// These are parameters for the alsa back end, the only back end that currently works with shairport-sync
-alsa =
+//
+// Back End Settings
+//
+
+// These are parameters for the alsa back end, the only back end that supports synchronisation
 {
 //  output_device = "default";
 //  mixer_type = "software"; // "software" or "hardware"
@@ -55,6 +62,14 @@ alsa =
 // These are parameters for the pipe back end, an experimental back end that directs output to a pipe.
 pipe =
 {
-//  name = "stdout";
+//  audio_backend_latency_offset = 0; // Set this offset to compensate for a fixed delay in the audio back end. E.g. if the output device delays by 100 ms, set this to -4410.
+//  audio_backend_buffer_desired_length = 44100;
+//  name = "/path/to/pipe"; // there is no default pipe name for the output
 };
 
+// These are parameters for the stdout back end, an experimental back end that directs output to stdout.
+stdout =
+{
+//  audio_backend_latency_offset = 0; // Set this offset to compensate for a fixed delay in the audio back end. E.g. if the output device delays by 100 ms, set this to -4410.
+//  audio_backend_buffer_desired_length = 44100;
+};