From ce79b5f952816d60a24f2602e84bfadf8e2a72ca Mon Sep 17 00:00:00 2001
From: Marcus Weseloh <marcus@weseloh.cc>
Date: Fri, 20 Oct 2017 15:51:20 +0200
Subject: [PATCH] Handle sample rate changes and change sample rate to unsigned
 long (as defined in ladspa.h)

---
 src/bindings/fluid_ladspa.c | 41 ++++++++++++++++++++++++++++++++++++-
 src/bindings/fluid_ladspa.h |  3 ++-
 src/synth/fluid_synth.c     | 12 ++++++++++-
 3 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/src/bindings/fluid_ladspa.c b/src/bindings/fluid_ladspa.c
index 6dcfff77..df2d2980 100644
--- a/src/bindings/fluid_ladspa.c
+++ b/src/bindings/fluid_ladspa.c
@@ -34,6 +34,8 @@
 
 #define LADSPA_API_ENTER(_fx) (fluid_rec_mutex_lock((_fx)->api_mutex))
 
+#define LADSPA_API_EXIT(_fx) (fluid_rec_mutex_unlock((_fx)->api_mutex))
+
 #define LADSPA_API_RETURN(_fx, _ret)          \
     fluid_rec_mutex_unlock((_fx)->api_mutex); \
     return (_ret);
@@ -88,7 +90,7 @@ fluid_ladspa_fx_t *new_fluid_ladspa_fx(fluid_synth_t *synth)
 
     fx->state = FLUID_LADSPA_INACTIVE;
 
-    fx->sample_rate = synth->sample_rate;
+    fx->sample_rate = (unsigned long)synth->sample_rate;
 
     fx->audio_groups = synth->audio_groups;
     fx->effects_channels = synth->effects_channels;
@@ -159,6 +161,43 @@ void delete_fluid_ladspa_fx(fluid_ladspa_fx_t *fx)
     FLUID_FREE(fx);
 };
 
+/**
+ * Set the sample rate of the LADSPA effects.
+ *
+ * Resets the LADSPA effects if the sample rate is different from the
+ * previous sample rate.
+ *
+ * @param fx LADSPA fx instance
+ * @param sample_rate new sample rate
+ */
+void fluid_ladspa_set_sample_rate(fluid_ladspa_fx_t *fx, fluid_synth_t *synth)
+{
+    unsigned long new_sample_rate = (unsigned long)synth->sample_rate;
+
+    LADSPA_API_ENTER(fx);
+
+    if (fx->sample_rate == new_sample_rate)
+    {
+        LADSPA_API_EXIT(fx);
+        return;
+    }
+
+    if (fluid_ladspa_is_active(fx))
+    {
+        if (fluid_ladspa_deactivate(fx, synth) != FLUID_OK)
+        {
+            FLUID_LOG(FLUID_ERR, "Failed to deactivate LADSPA, unable to change sample rate");
+            LADSPA_API_EXIT(fx);
+            return;
+        }
+    }
+
+    clear_ladspa(fx);
+    fx->sample_rate = new_sample_rate;
+
+    LADSPA_API_EXIT(fx);
+}
+
 /**
  * Check if the LADSPA engine is in use by FluidSynth.
  *
diff --git a/src/bindings/fluid_ladspa.h b/src/bindings/fluid_ladspa.h
index c0b4f971..5fb41579 100644
--- a/src/bindings/fluid_ladspa.h
+++ b/src/bindings/fluid_ladspa.h
@@ -94,7 +94,7 @@ typedef struct _fluid_ladspa_node_t
 
 typedef struct _fluid_ladspa_fx_t
 {
-    int sample_rate;
+    unsigned long sample_rate;
 
     int audio_groups;
     int effects_channels;
@@ -124,6 +124,7 @@ typedef struct _fluid_ladspa_fx_t
 
 fluid_ladspa_fx_t *new_fluid_ladspa_fx(fluid_synth_t *synth);
 void delete_fluid_ladspa_fx(fluid_ladspa_fx_t *fx);
+void fluid_ladspa_set_sample_rate(fluid_ladspa_fx_t *fx, fluid_synth_t *synth);
 
 int fluid_ladspa_is_active(fluid_ladspa_fx_t *fx);
 int fluid_ladspa_activate(fluid_ladspa_fx_t *fx, fluid_synth_t *synth);
diff --git a/src/synth/fluid_synth.c b/src/synth/fluid_synth.c
index 329bfe9a..6f8c481d 100644
--- a/src/synth/fluid_synth.c
+++ b/src/synth/fluid_synth.c
@@ -2350,7 +2350,7 @@ fluid_synth_update_presets(fluid_synth_t* synth)
   }
 }
 
-/* Handler for synth.gain setting. */
+/* Handler for synth.sample-rate setting. */
 static int
 fluid_synth_update_sample_rate(fluid_synth_t* synth, char* name, double value)
 {
@@ -2383,6 +2383,16 @@ fluid_synth_set_sample_rate(fluid_synth_t* synth, float sample_rate)
   fluid_synth_update_mixer(synth, fluid_rvoice_mixer_set_samplerate, 
 			   0, sample_rate);
   fluid_synth_api_exit(synth);
+
+#ifdef LADSPA
+  /* Signal sample rate change to LADSPA effects. Called after releasing the
+   * synth api, as LADSPA might need to wait for rvoice mixer to deactivate
+   * the effects unit first. */
+  if (synth->ladspa_fx != NULL)
+  {
+    fluid_ladspa_set_sample_rate(synth->ladspa_fx, synth);
+  }
+#endif
 }