Disable hacky attempt to sync visualization with audio by default

CHANGELOG.md

@@ -20,6 +20,8 @@
   configuration file for controlling the look of the new spectrum visualizer.
 * Add `visualizer_autoscale` option to a configuration file.
 * Allow for editing multiple titles in the Tag Editor.
+* Allow setting `visualizer_sync_interval` to 0 (a new default) to disable
+  synchronization attempts.
 
 # ncmpcpp-0.8.2 (2018-04-11)
 * Help screen: fixed display of EoF keycode

doc/config

@@ -69,13 +69,11 @@
 #visualizer_in_stereo = yes
 #
 ##
-## Note: Below parameter defines how often ncmpcpp has to "synchronize"
+## Note: set below to >=10 only if you have synchronization issues with
-## visualizer and audio outputs.  30 seconds is optimal value, but if you
+## visualization and audio.
-## experience synchronization problems, set it to lower value.  Keep in mind
-## that sane values start with >=10.
 ##
 #
-#visualizer_sync_interval = 30
+#visualizer_sync_interval = 0
 #
 ##
 ## Note: To enable spectrum frequency visualization you need to compile ncmpcpp

doc/ncmpcpp.1

@@ -88,7 +88,8 @@ Name of output that provides data for visualizer. Needed to keep sound and visua
 Should be set to 'yes', if fifo output's format was set to 44100:16:2.
 .TP
 .B visualizer_sync_interval = SECONDS
-Defines interval between syncing visualizer and audio outputs.
+Try synchronizing visualization with audio every N seconds by flushing the FIFO
+output. A value of 0 disables it, use only when necessary.
 .TP
 .B visualizer_type = spectrum/wave/wave_filled/ellipse
 Defines default visualizer type (spectrum is available only if ncmpcpp was compiled with fftw support).

src/screens/visualizer.cpp

@@ -160,6 +160,8 @@ void Visualizer::update()
 		memcpy(sdata_end - data, temp_sdata, data);
 	}
 
+	if (Config.visualizer_sync_interval > boost::posix_time::seconds(0))
+	{
 		if (m_output_id != -1 && Global::Timer - m_timer > Config.visualizer_sync_interval)
 		{
 			Mpd.DisableOutput(m_output_id);
@@ -167,6 +169,7 @@ void Visualizer::update()
 			Mpd.EnableOutput(m_output_id);
 			m_timer = Global::Timer;
 		}
+	}
 
 	void (Visualizer::*draw)(int16_t *, ssize_t, size_t, size_t);
 	void (Visualizer::*drawStereo)(int16_t *, int16_t *, ssize_t, size_t);

src/settings.cpp

@@ -279,9 +279,10 @@ bool Configuration::read(const std::vector<std::string> &config_paths, bool igno
 	p.add("visualizer_fifo_path", &visualizer_fifo_path, "/tmp/mpd.fifo", adjust_path);
 	p.add("visualizer_output_name", &visualizer_output_name, "Visualizer feed");
 	p.add("visualizer_in_stereo", &visualizer_in_stereo, "yes", yes_no);
-	p.add("visualizer_sync_interval", &visualizer_sync_interval, "30",
+	p.add("visualizer_sync_interval", &visualizer_sync_interval, "0",
 	      [](std::string v) {
 		      unsigned sync_interval = verbose_lexical_cast<unsigned>(v);
+		      if (sync_interval > 0)
 			      lowerBoundCheck<unsigned>(sync_interval, 10);
 		      return boost::posix_time::seconds(sync_interval);
 	});