support user-defined interval between syncing visualizer and audio outputs

doc/config

@@ -47,6 +47,16 @@
 #visualizer_output_name = ""
 #
 ##
+## Note: Below parameter defines how often ncmpcpp
+## has to "synchronize" visualizer and audio outputs.
+## 30 seconds is optimal value, but if you experience
+## synchronization problems, set it to lower value.
+## Keep in mind that sane values start with >=10.
+##
+#
+#visualizer_sync_interval = "30"
+#
+##
 ## Note: To enable spectrum frequency visualization
 ## you need to compile ncmpcpp with fftw3 support.
 ##

doc/ncmpcpp.1

@@ -78,6 +78,9 @@ Path to mpd fifo output. This is needed to make music visualizer work (note that
 .B visualizer_output_name = NAME
 Name of output that provides data for visualizer. Needed to keep sound and visualization in sync.
 .TP
+.B visualizer_sync_interval = SECONDS
+Defines interval between syncing visualizer and audio outputs.
+.TP
 .B visualizer_type = spectrum/wave
 Defines default visualizer type (spectrum is available only if ncmpcpp was compiled with fftw support).
 .TP