Fix: reset pipeline stages when context unmanaged

This addresses an issue where internal speech processor state
was available after the speech context left the "externally
managed" state, sometimes leading to a false reactivation if
a wakeword activation was pending before the stages' processing
of the audio buffer was interrupted.

Due to the new interface method required by this fix, it is a
breaking change.

src/main/java/io/spokestack/spokestack/ActivationTimeout.java

@@ -71,14 +71,12 @@ private void deactivate(SpeechContext context) {
     }
 
     @Override
-    public void close() {
-        reset();
+    public void reset() {
+        close();
     }
 
-    /**
-     * Reset the trigger's activity timer.
-     */
-    public void reset() {
+    @Override
+    public void close() {
         this.activeLength = 0;
     }
 }

src/main/java/io/spokestack/spokestack/SpeechPipeline.java

@@ -75,6 +75,7 @@ public final class SpeechPipeline implements AutoCloseable {
     private List<SpeechProcessor> stages;
     private Thread thread;
     private boolean running;
+    private boolean managed;
 
     /**
      * initializes a new speech pipeline instance.
@@ -228,9 +229,18 @@ private void dispatch() {
             // fill the frame from the input
             this.input.read(this.context, frame);
 
-            // dispatch the frame to the stages
-            if (!this.context.isManaged()) {
+            // when leaving the managed state, reset all stages internally
+            boolean isManaged = this.context.isManaged();
+            if (this.managed && !isManaged) {
                 for (SpeechProcessor stage : this.stages) {
+                    stage.reset();
+                }
+            }
+            this.managed = isManaged;
+
+            // dispatch the frame to the stages
+            for (SpeechProcessor stage : this.stages) {
+                if (!this.managed) {
                     frame.rewind();
                     stage.process(this.context, frame);
                 }

src/main/java/io/spokestack/spokestack/SpeechProcessor.java

@@ -24,4 +24,10 @@ public interface SpeechProcessor extends AutoCloseable {
      * @throws Exception on error
      */
     void process(SpeechContext context, ByteBuffer frame) throws Exception;
+
+    /**
+     * resets all state internal to the stage.
+     * @throws Exception on error
+     */
+    void reset() throws Exception;
 }

src/main/java/io/spokestack/spokestack/SpeechSampler.java

@@ -77,6 +77,11 @@ public SpeechSampler(SpeechConfig config) throws Exception {
         this.header.putInt(Integer.MAX_VALUE);      // size of data chunk
     }
 
+    @Override
+    public void reset() throws Exception {
+        close();
+    }
+
     /**
      * destroys the resources attached to the copmonent.
      * @throws Exception on error

src/main/java/io/spokestack/spokestack/android/AndroidSpeechRecognizer.java

@@ -157,9 +157,17 @@ Intent createRecognitionIntent() {
         return intent;
     }
 
+    @Override
+    public void reset() {
+       close();
+    }
+
     @Override
     public void close() {
-        this.taskHandler.run(() -> this.speechRecognizer.destroy());
+        this.taskHandler.run(() -> {
+            this.speechRecognizer.destroy();
+            this.speechRecognizer = null;
+        });
     }
 
     /**

src/main/java/io/spokestack/spokestack/asr/SpokestackCloudRecognizer.java

@@ -78,9 +78,19 @@ public SpokestackCloudRecognizer(
               .build();
     }
 
+    @Override
+    public void reset() {
+        if (this.client.isConnected()) {
+            this.client.disconnect();
+        }
+        this.idleCount = 0;
+        this.active = false;
+    }
+
     /**
      * releases the resources associated with the recognizer.
      */
+    @Override
     public void close() {
         this.client.close();
     }

src/main/java/io/spokestack/spokestack/google/GoogleSpeechRecognizer.java

@@ -103,13 +103,21 @@ private void configure(SpeechConfig speechConfig) throws Exception {
             .build();
     }
 
+    @Override
+    public void reset() {
+        if (this.request != null) {
+            this.request.onCompleted();
+        }
+    }
+
     /**
      * releases the resources associated with the recognizer.
-     * @throws Exception on error
      */
-    public void close() throws Exception {
-        if (this.request != null)
+    @Override
+    public void close() {
+        if (this.request != null) {
             this.request.onCompleted();
+        }
         this.client.close();
     }
 

src/main/java/io/spokestack/spokestack/microsoft/AzureSpeechRecognizer.java

@@ -106,9 +106,15 @@ com.microsoft.cognitiveservices.speech.SpeechConfig createMsConfig(
         return config;
     }
 
+    @Override
+    public void reset() {
+        close();
+    }
+
     /**
      * releases the resources associated with the recognizer.
      */
+    @Override
     public void close() {
         if (this.audioStream != null) {
             this.audioStream.close();

src/main/java/io/spokestack/spokestack/wakeword/WakewordTrigger.java

@@ -315,6 +315,25 @@ public void close() throws Exception {
         this.detectModel.close();
     }
 
+    @Override
+    public void reset() {
+        // empty the sample buffer, so that only contiguous
+        // speech samples are written to it
+        this.sampleWindow.reset();
+
+        // reset and fill the other buffers,
+        // which prevents them from lagging the detection
+        this.frameWindow.reset().fill(0);
+        this.encodeWindow.reset().fill(0);
+
+        // reset the encoder states
+        while (this.encodeModel.states().hasRemaining())
+            this.encodeModel.states().putFloat(0);
+
+        // reset the maximum posterior
+        this.posteriorMax = 0;
+    }
+
     /**
      * processes a frame of audio.
      * @param context the current speech context
@@ -337,7 +356,7 @@ public void process(SpeechContext context, ByteBuffer buffer)
         if (vadFall) {
             if (!context.isActive())
                 trace(context);
-            reset(context);
+            reset();
         }
     }
 
@@ -460,24 +479,6 @@ private void activate(SpeechContext context) {
         context.setActive(true);
     }
 
-    private void reset(SpeechContext context) {
-        // empty the sample buffer, so that only contiguous
-        // speech samples are written to it
-        this.sampleWindow.reset();
-
-        // reset and fill the other buffers,
-        // which prevents them from lagging the detection
-        this.frameWindow.reset().fill(0);
-        this.encodeWindow.reset().fill(0);
-
-        // reset the encoder states
-        while (this.encodeModel.states().hasRemaining())
-            this.encodeModel.states().putFloat(0);
-
-        // reset the maximum posterior
-        this.posteriorMax = 0;
-    }
-
     private void trace(SpeechContext context) {
         context.traceInfo(String.format("wake: %f", this.posteriorMax));
     }

src/main/java/io/spokestack/spokestack/webrtc/AcousticNoiseSuppressor.java

@@ -95,9 +95,14 @@ else if (policyString.equals("very-aggressive"))
             throw new OutOfMemoryError();
     }
 
+    @Override
+    public void reset() {
+    }
+
     /**
      * destroys the unmanaged ans instance.
      */
+    @Override
     public void close() {
         destroy(this.ansHandle);
     }

src/main/java/io/spokestack/spokestack/webrtc/AutomaticGainControl.java

@@ -101,6 +101,10 @@ public void close() {
         destroy(this.agcHandle);
     }
 
+    @Override
+    public void reset() {
+    }
+
     /**
      * processes a frame of audio.
      * @param context the current speech context

src/main/java/io/spokestack/spokestack/webrtc/VoiceActivityDetector.java

@@ -166,6 +166,12 @@ public void process(SpeechContext context, ByteBuffer frame) {
         }
     }
 
+    @Override
+    public void reset() {
+        this.runValue = false;
+        this.runLength = 0;
+    }
+
     //-----------------------------------------------------------------------
     // native interface
     //-----------------------------------------------------------------------

src/main/java/io/spokestack/spokestack/webrtc/VoiceActivityTrigger.java

@@ -46,4 +46,9 @@ public void process(SpeechContext context, ByteBuffer frame) {
             this.isSpeech = context.isSpeech();
         }
     }
+
+    @Override
+    public void reset() {
+        this.isSpeech = false;
+    }
 }

src/test/java/io/spokestack/spokestack/SpeechPipelineTest.java

@@ -282,6 +282,10 @@ public Stage(SpeechConfig config) {
             open = true;
         }
 
+        public void reset() {
+            close();
+        }
+
         public void close() {
             open = false;
         }
@@ -322,6 +326,10 @@ public static class FailStage implements SpeechProcessor {
         public FailStage(SpeechConfig config) {
         }
 
+        public void reset() throws Exception {
+            close();
+        }
+
         public void close() throws Exception {
             throw new Exception("fail");
         }
@@ -337,6 +345,10 @@ public ConfigRequiredStage(SpeechConfig config) {
             config.getString("required-property");
         }
 
+        public void reset() throws Exception {
+            close();
+        }
+
         public void close() throws Exception {
             throw new Exception("fail");
         }