Added fluid_synth_get_active_voice_count().

fluidsynth/doc/fluidsynth-v11-devdoc.txt

@@ -102,7 +102,8 @@ API additions:
 - Additional synthesizer API: fluid_synth_get_sfont_by_name() to get a SoundFont by name,
   fluid_synth_program_select_by_sfont_name() to select an instrument by SoundFont name/bank/program,
   fluid_synth_set_gen2() for specifying additional parameters when assigning a generator value,
-  and fluid_synth_sysex() for sending SYSEX messages to the synth.
+  fluid_synth_sysex() for sending SYSEX messages to the synth and fluid_synth_get_active_voice_count() to
+  get the current number of active synthesis voices.
 - Miscellaneous additions: fluid_player_set_loop() to set playlist loop count and fluid_player_get_status() to get current player state.
 
 

fluidsynth/include/fluidsynth/synth.h

@@ -162,6 +162,7 @@ FLUIDSYNTH_API void fluid_synth_set_gain(fluid_synth_t* synth, float gain);
 FLUIDSYNTH_API float fluid_synth_get_gain(fluid_synth_t* synth);
 FLUIDSYNTH_API int fluid_synth_set_polyphony(fluid_synth_t* synth, int polyphony);
 FLUIDSYNTH_API int fluid_synth_get_polyphony(fluid_synth_t* synth);
+FLUIDSYNTH_API int fluid_synth_get_active_voice_count(fluid_synth_t* synth);
 FLUIDSYNTH_API int fluid_synth_get_internal_bufsize(fluid_synth_t* synth);
 
 FLUIDSYNTH_API 

fluidsynth/src/fluid_cmd.c

@@ -48,6 +48,8 @@ static int fluid_shell_run(fluid_shell_t* shell);
 static void fluid_shell_init(fluid_shell_t* shell,
                              fluid_settings_t* settings, fluid_cmd_handler_t* handler,
                              fluid_istream_t in, fluid_ostream_t out);
+static int fluid_handle_voice_count (fluid_synth_t *synth, int ac, char **av,
+                                     fluid_ostream_t out);
 
 void fluid_shell_settings(fluid_settings_t* settings)
 {
@@ -113,6 +115,8 @@ fluid_cmd_t fluid_commands[] = {
     "chorus [0|1|on|off]        Turn the chorus on or off" },
   { "gain", "general", (fluid_cmd_func_t) fluid_handle_gain, NULL,
     "gain value                 Set the master gain (0 < gain < 5)" },
+  { "voice_count", "general", (fluid_cmd_func_t) fluid_handle_voice_count, NULL,
+    "voice_count                Get number of active synthesis voices" },
   { "tuning", "tuning", (fluid_cmd_func_t) fluid_handle_tuning, NULL,
     "tuning name bank prog      Create a tuning with name, bank number, \n"
     "                           and program number (0 <= bank,prog <= 127)" },
@@ -946,6 +950,16 @@ fluid_handle_gain(fluid_synth_t* synth, int ac, char** av, fluid_ostream_t out)
   return 0;
 }
 
+/* Response to voice_count command */
+static int
+fluid_handle_voice_count (fluid_synth_t *synth, int ac, char **av,
+                          fluid_ostream_t out)
+{
+  fluid_ostream_printf (out, "voice_count: %d\n",
+                        fluid_synth_get_active_voice_count (synth));
+  return FLUID_OK;
+}
+
 /* Purpose:
  * Response to 'interp' command. */
 int

fluidsynth/src/fluid_synth.c

@@ -2618,6 +2618,23 @@ fluid_synth_get_polyphony(fluid_synth_t* synth)
   return fluid_atomic_int_get (&synth->polyphony);
 }
 
+/**
+ * Get current number of active voices.
+ * @param synth FluidSynth instance
+ * @return Number of currently active voices.
+ * @since 1.1.0
+ *
+ * Note: To generate accurate continuous statistics of the voice count, caller
+ * should ensure this function is called synchronously with the audio synthesis
+ * process.  This can be done in the new_fluid_audio_driver2() audio callback
+ * function for example.
+ */
+int
+fluid_synth_get_active_voice_count(fluid_synth_t* synth)
+{
+  return fluid_atomic_int_get (&synth->active_voice_count);
+}
+
 /**
  * Get the internal synthesis buffer size value.
  * @param synth FluidSynth instance

fluidsynth/src/fluid_synth.h

@@ -138,15 +138,16 @@ typedef struct _fluid_sfont_info_t {
  * outbuf
  * sample_timers
  *
- * Only synth thread changes
+ * Only synth thread changes (atomic operations for non-synth thread reads)
  * -------------------------
  * ticks
  * reverb{}
  * chorus{}
  * cur
  * dither_index
- * polyphony (atomic int get for non-synth threads)
+ * polyphony
  * st_gain
+ * active_voice_count
  */
 
 struct _fluid_synth_t
@@ -187,6 +188,7 @@ struct _fluid_synth_t
   fluid_channel_t** channel;         /**< the channels */
   int nvoice;                        /**< the length of the synthesis process array (max polyphony allowed) */
   fluid_voice_t** voice;             /**< the synthesis voices */
+  int active_voice_count;            /**< count of active voices */
   unsigned int noteid;               /**< the id is incremented for every new note. it's used for noteoff's  */
   unsigned int storeid;
   int nbuf;                          /**< How many audio buffers are used? (depends on nr of audio channels / groups)*/

fluidsynth/src/fluid_voice.c

@@ -829,6 +829,9 @@ void fluid_voice_start(fluid_voice_t* voice)
   voice->ref = fluid_profile_ref();
 
   voice->status = FLUID_VOICE_ON;
+
+  /* Increment voice count atomically, for non-synth thread read access */
+  fluid_atomic_int_add (&voice->channel->synth->active_voice_count, 1);
 }
 
 void 
@@ -1690,6 +1693,9 @@ fluid_voice_off(fluid_voice_t* voice)
     voice->sample = NULL;
   }
 
+  /* Decrement voice count atomically, for non-synth thread read access */
+  fluid_atomic_int_add (&voice->channel->synth->active_voice_count, -1);
+
   return FLUID_OK;
 }