Added method AudioProcessor::silenceInProducesSilenceOut().

modules/juce_audio_processors/format_types/juce_AudioUnitPluginFormat.mm

@@ -367,6 +367,19 @@ public:
 
     void* getPlatformSpecificData()             { return audioUnit; }
     const String getName() const                { return pluginName; }
+
+    bool silenceInProducesSilenceOut() const
+    {
+        Float64 tail = 0;
+        UInt32 tailSize = sizeof (tail);
+
+        if (audioUnit != 0)
+            AudioUnitGetProperty (audioUnit, kAudioUnitProperty_TailTime, kAudioUnitScope_Global,
+                                  0, &tail, &tailSize);
+
+        return tail <= 0;
+    }
+
     bool acceptsMidi() const                    { return wantsMidiMessages; }
     bool producesMidi() const                   { return producesMidiMessages; }
 

modules/juce_audio_processors/format_types/juce_VSTPluginFormat.cpp

@@ -871,8 +871,8 @@ public:
         setLatencySamples (effect->initialDelay);
     }
 
-    void* getPlatformSpecificData()         { return effect; }
-    const String getName() const            { return name; }
+    void* getPlatformSpecificData()  { return effect; }
+    const String getName() const     { return name; }
 
     int getUID() const
     {
@@ -884,8 +884,13 @@ public:
         return uid;
     }
 
-    bool acceptsMidi() const                { return wantsMidiMessages; }
-    bool producesMidi() const               { return dispatch (effCanDo, 0, 0, (void*) "sendVstMidiEvent", 0) > 0; }
+    bool silenceInProducesSilenceOut() const
+    {
+        return effect == nullptr || (effect->flags & effFlagsNoSoundInStop) != 0;
+    }
+
+    bool acceptsMidi() const    { return wantsMidiMessages; }
+    bool producesMidi() const   { return dispatch (effCanDo, 0, 0, (void*) "sendVstMidiEvent", 0) > 0; }
 
     //==============================================================================
     void prepareToPlay (double rate, int samplesPerBlockExpected)

modules/juce_audio_processors/processors/juce_AudioProcessor.h

@@ -239,6 +239,9 @@ public:
     */
     void setLatencySamples (int newLatency);
 
+    /** Returns true if a silent input always produces a silent output (i.e. it has no tail). */
+    virtual bool silenceInProducesSilenceOut() const = 0;
+
     /** Returns true if the processor wants midi messages. */
     virtual bool acceptsMidi() const = 0;
 

modules/juce_audio_processors/processors/juce_AudioProcessorGraph.cpp

@@ -1322,6 +1322,7 @@ const String AudioProcessorGraph::getOutputChannelName (int channelIndex) const
 
 bool AudioProcessorGraph::isInputChannelStereoPair (int /*index*/) const    { return true; }
 bool AudioProcessorGraph::isOutputChannelStereoPair (int /*index*/) const   { return true; }
+bool AudioProcessorGraph::silenceInProducesSilenceOut() const               { return false; }
 bool AudioProcessorGraph::acceptsMidi() const   { return true; }
 bool AudioProcessorGraph::producesMidi() const  { return true; }
 void AudioProcessorGraph::getStateInformation (juce::MemoryBlock& /*destData*/)   {}
@@ -1423,6 +1424,11 @@ void AudioProcessorGraph::AudioGraphIOProcessor::processBlock (AudioSampleBuffer
     }
 }
 
+bool AudioProcessorGraph::AudioGraphIOProcessor::silenceInProducesSilenceOut() const
+{
+    return isOutput();
+}
+
 bool AudioProcessorGraph::AudioGraphIOProcessor::acceptsMidi() const
 {
     return type == midiOutputNode;

modules/juce_audio_processors/processors/juce_AudioProcessorGraph.h

@@ -320,6 +320,7 @@ public:
         const String getOutputChannelName (int channelIndex) const;
         bool isInputChannelStereoPair (int index) const;
         bool isOutputChannelStereoPair (int index) const;
+        bool silenceInProducesSilenceOut() const;
         bool acceptsMidi() const;
         bool producesMidi() const;
 
@@ -364,6 +365,7 @@ public:
     const String getOutputChannelName (int channelIndex) const;
     bool isInputChannelStereoPair (int index) const;
     bool isOutputChannelStereoPair (int index) const;
+    bool silenceInProducesSilenceOut() const;
 
     bool acceptsMidi() const;
     bool producesMidi() const;