Add native microphone VAD input

Author: enfp-dev-studio

NitroWebrtcVad.podspec

@@ -36,5 +36,6 @@ Pod::Spec.new do |s|
 
   s.dependency 'React-jsi'
   s.dependency 'React-callinvoker'
+  s.frameworks = 'AVFoundation'
   install_modules_dependencies(s)
 end

android/src/main/AndroidManifest.xml

@@ -1,2 +1,3 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
+  <uses-permission android:name="android.permission.RECORD_AUDIO" />
 </manifest>

android/src/main/java/com/nitrowebrtcvad/NitroWebrtcVadAudioInput.java

@@ -0,0 +1,117 @@
+package com.nitrowebrtcvad;
+
+import android.media.AudioFormat;
+import android.media.AudioRecord;
+import android.media.MediaRecorder;
+import android.util.Log;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+final class NitroWebrtcVadAudioInput {
+  private static final String TAG = "NitroWebrtcVadAudio";
+
+  private static final AtomicBoolean isRecording = new AtomicBoolean(false);
+  private static AudioRecord audioRecord;
+  private static Thread recordingThread;
+
+  private NitroWebrtcVadAudioInput() {}
+
+  static synchronized void start(int sampleRate, int frameSamples) {
+    stop();
+
+    int minBufferSize = AudioRecord.getMinBufferSize(
+      sampleRate,
+      AudioFormat.CHANNEL_IN_MONO,
+      AudioFormat.ENCODING_PCM_16BIT
+    );
+    if (minBufferSize <= 0) {
+      throw new IllegalStateException("Failed to resolve Android AudioRecord buffer size.");
+    }
+
+    int frameBytes = frameSamples * 2;
+    int bufferSize = Math.max(minBufferSize, frameBytes * 4);
+
+    audioRecord = new AudioRecord(
+      MediaRecorder.AudioSource.VOICE_RECOGNITION,
+      sampleRate,
+      AudioFormat.CHANNEL_IN_MONO,
+      AudioFormat.ENCODING_PCM_16BIT,
+      bufferSize
+    );
+
+    if (audioRecord.getState() != AudioRecord.STATE_INITIALIZED) {
+      releaseAudioRecord();
+      throw new IllegalStateException("Failed to initialize Android AudioRecord.");
+    }
+
+    audioRecord.startRecording();
+    isRecording.set(true);
+
+    recordingThread = new Thread(() -> readLoop(frameSamples), "NitroWebrtcVadAudioInput");
+    recordingThread.start();
+  }
+
+  static synchronized void stop() {
+    isRecording.set(false);
+    if (audioRecord != null) {
+      try {
+        audioRecord.stop();
+      } catch (IllegalStateException ignored) {
+      }
+    }
+    if (recordingThread != null) {
+      try {
+        recordingThread.join(300);
+      } catch (InterruptedException ignored) {
+        Thread.currentThread().interrupt();
+      }
+      recordingThread = null;
+    }
+    releaseAudioRecord();
+  }
+
+  private static void readLoop(int frameSamples) {
+    short[] frame = new short[frameSamples];
+
+    while (isRecording.get()) {
+      int offset = 0;
+      while (isRecording.get() && offset < frameSamples) {
+        AudioRecord recorder = audioRecord;
+        if (recorder == null) {
+          return;
+        }
+
+        int read = recorder.read(frame, offset, frameSamples - offset);
+        if (read < 0) {
+          Log.e(TAG, "AudioRecord read failed code=" + read);
+          isRecording.set(false);
+          return;
+        }
+        offset += read;
+      }
+
+      if (isRecording.get() && offset == frameSamples) {
+        try {
+          onAudioFrame(frame);
+        } catch (UnsatisfiedLinkError error) {
+          Log.e(TAG, "Native audio frame callback is not linked.", error);
+          isRecording.set(false);
+          return;
+        } catch (RuntimeException error) {
+          Log.e(TAG, "Native audio frame callback failed.", error);
+          isRecording.set(false);
+          return;
+        }
+      }
+    }
+  }
+
+  private static void releaseAudioRecord() {
+    if (audioRecord != null) {
+      audioRecord.release();
+      audioRecord = null;
+    }
+  }
+
+  private static native void onAudioFrame(short[] audioFrame);
+}