private int initRecording(int sampleRate, int channels) {
? ? Logging.d(TAG, "initRecording(sampleRate=" + sampleRate + ", channels=" + channels + ")");
? ? if (audioRecord != null) {
? ? ? reportWebRtcAudioRecordInitError("InitRecording called twice without StopRecording.");
? ? ? return -1;
? ? }
? ? final int bytesPerFrame = channels * (BITS_PER_SAMPLE / 8);
? ? final int framesPerBuffer = sampleRate / BUFFERS_PER_SECOND;
? ? byteBuffer = ByteBuffer.allocateDirect(bytesPerFrame * framesPerBuffer);
? ? Logging.d(TAG, "byteBuffer.capacity: " + byteBuffer.capacity());
? ? emptyBytes = new byte[byteBuffer.capacity()];
? ? // Rather than passing the ByteBuffer with every callback (requiring
? ? // the potentially expensive GetDirectBufferAddress) we simply have the
? ? // the native class cache the address to the memory once.
? ? nativeCacheDirectBufferAddress(byteBuffer, nativeAudioRecord);

? ? // Get the minimum buffer size required for the successful creation of
? ? // an AudioRecord object, in byte units.
? ? // Note that this size doesn't guarantee a smooth recording under load.
? ? final int channelConfig = channelCountToConfiguration(channels);
? ? int minBufferSize =
? ? ? ? AudioRecord.getMinBufferSize(sampleRate, channelConfig, AudioFormat.ENCODING_PCM_16BIT);
? ? if (minBufferSize == AudioRecord.ERROR || minBufferSize == AudioRecord.ERROR_BAD_VALUE) {
? ? ? reportWebRtcAudioRecordInitError("AudioRecord.getMinBufferSize failed: " + minBufferSize);
? ? ? return -1;
? ? }
? ? Logging.d(TAG, "AudioRecord.getMinBufferSize: " + minBufferSize);

? ? // Use a larger buffer size than the minimum required when creating the
? ? // AudioRecord instance to ensure smooth recording under load. It has been
? ? // verified that it does not increase the actual recording latency.
? ? int bufferSizeInBytes = Math.max(BUFFER_SIZE_FACTOR * minBufferSize, byteBuffer.capacity());
? ? Logging.d(TAG, "bufferSizeInBytes: " + bufferSizeInBytes);
? ? try {
? ? ? audioRecord = new AudioRecord(audioSource, sampleRate, channelConfig,
? ? ? ? ? AudioFormat.ENCODING_PCM_16BIT, bufferSizeInBytes);
? ? } catch (IllegalArgumentException e) {
? ? ? reportWebRtcAudioRecordInitError("AudioRecord ctor error: " + e.getMessage());
? ? ? releaseAudioResources();
? ? ? return -1;
? ? }
? ? if (audioRecord == null || audioRecord.getState() != AudioRecord.STATE_INITIALIZED) {
? ? ? reportWebRtcAudioRecordInitError("Failed to create a new AudioRecord instance");
? ? ? releaseAudioResources();
? ? ? return -1;
? ? }
? ? if (effects != null) {
? ? ? effects.enable(audioRecord.getAudioSessionId());
? ? }
? ? logMainParameters();
? ? logMainParametersExtended();
? ? return framesPerBuffer;
? }

private boolean startRecording() {
? ? Logging.d(TAG, "startRecording");
? ? assertTrue(audioRecord != null);
? ? assertTrue(audioThread == null);
? ? try {
? ? ? audioRecord.startRecording();
? ? } catch (IllegalStateException e) {
? ? ? reportWebRtcAudioRecordStartError(AudioRecordStartErrorCode.AUDIO_RECORD_START_EXCEPTION,
? ? ? ? ? "AudioRecord.startRecording failed: " + e.getMessage());
? ? ? return false;
? ? }
? ? if (audioRecord.getRecordingState() != AudioRecord.RECORDSTATE_RECORDING) {
? ? ? reportWebRtcAudioRecordStartError(
? ? ? ? ? AudioRecordStartErrorCode.AUDIO_RECORD_START_STATE_MISMATCH,
? ? ? ? ? "AudioRecord.startRecording failed - incorrect state :"
? ? ? ? ? + audioRecord.getRecordingState());
? ? ? return false;
? ? }
? ? audioThread = new AudioRecordThread("AudioRecordJavaThread");
? ? audioThread.start();
? ? return true;
? }

?private class AudioRecordThread extends Thread {
? ? private volatile boolean keepAlive = true;

? ? public AudioRecordThread(String name) {
? ? ? super(name);
? ? }

? ? // TODO(titovartem) make correct fix during webrtc:9175
? ? @SuppressWarnings("ByteBufferBackingArray")
? ? @Override
? ? public void run() {
? ? ? Process.setThreadPriority(Process.THREAD_PRIORITY_URGENT_AUDIO);
? ? ? Logging.d(TAG, "AudioRecordThread" + WebRtcAudioUtils.getThreadInfo());
? ? ? assertTrue(audioRecord.getRecordingState() == AudioRecord.RECORDSTATE_RECORDING);

? ? ? long lastTime = System.nanoTime();
? ? ? while (keepAlive) {
? ? ? ? int bytesRead = audioRecord.read(byteBuffer, byteBuffer.capacity());
? ? ? ? if (bytesRead == byteBuffer.capacity()) {
? ? ? ? ? if (microphoneMute) {
? ? ? ? ? ? byteBuffer.clear();
? ? ? ? ? ? byteBuffer.put(emptyBytes);
? ? ? ? ? }
? ? ? ? ? // It's possible we've been shut down during the read, and stopRecording() tried and
? ? ? ? ? // failed to join this thread. To be a bit safer, try to avoid calling any native methods
? ? ? ? ? // in case they've been unregistered after stopRecording() returned.
? ? ? ? ? if (keepAlive) {
? ? ? ? ? ? nativeDataIsRecorded(bytesRead, nativeAudioRecord);
? ? ? ? ? }
? ? ? ? ? if (audioSamplesReadyCallback != null) {
? ? ? ? ? ? // Copy the entire byte buffer array. ?Assume that the start of the byteBuffer is
? ? ? ? ? ? // at index 0.
? ? ? ? ? ? byte[] data = Arrays.copyOf(byteBuffer.array(), byteBuffer.capacity());
? ? ? ? ? ? audioSamplesReadyCallback.onWebRtcAudioRecordSamplesReady(
? ? ? ? ? ? ? ? new AudioSamples(audioRecord, data));
? ? ? ? ? }
? ? ? ? } else {
? ? ? ? ? String errorMessage = "AudioRecord.read failed: " + bytesRead;
? ? ? ? ? Logging.e(TAG, errorMessage);
? ? ? ? ? if (bytesRead == AudioRecord.ERROR_INVALID_OPERATION) {
? ? ? ? ? ? keepAlive = false;
? ? ? ? ? ? reportWebRtcAudioRecordError(errorMessage);
? ? ? ? ? }
? ? ? ? }
? ? ? ? if (DEBUG) {
? ? ? ? ? long nowTime = System.nanoTime();
? ? ? ? ? long durationInMs = TimeUnit.NANOSECONDS.toMillis((nowTime - lastTime));
? ? ? ? ? lastTime = nowTime;
? ? ? ? ? Logging.d(TAG, "bytesRead[" + durationInMs + "] " + bytesRead);
? ? ? ? }
? ? ? }

? ? ? try {
? ? ? ? if (audioRecord != null) {
? ? ? ? ? audioRecord.stop();
? ? ? ? }
? ? ? } catch (IllegalStateException e) {
? ? ? ? Logging.e(TAG, "AudioRecord.stop failed: " + e.getMessage());
? ? ? }
? ? }

? ? // Stops the inner thread loop and also calls AudioRecord.stop().
? ? // Does not block the calling thread.
? ? public void stopThread() {
? ? ? Logging.d(TAG, "stopThread");
? ? ? keepAlive = false;
? ? }
? }

? private boolean stopRecording() {
? ? Logging.d(TAG, "stopRecording");
? ? assertTrue(audioThread != null);
? ? audioThread.stopThread();
? ? if (!ThreadUtils.joinUninterruptibly(audioThread, AUDIO_RECORD_THREAD_JOIN_TIMEOUT_MS)) {
? ? ? Logging.e(TAG, "Join of AudioRecordJavaThread timed out");
? ? ? WebRtcAudioUtils.logAudioState(TAG);
? ? }
? ? audioThread = null;
? ? if (effects != null) {
? ? ? effects.release();
? ? }
? ? releaseAudioResources();
? ? return true;
? }