import android.media.audiofx.AcousticEchoCanceler; //導入方法依賴的package包/類

@Override

public boolean initCapturer() {

// initalize audio mode

audioManagerMode.acquireMode(audioManager);

// get the minimum buffer size that can be used

int minRecBufSize = AudioRecord.getMinBufferSize(

captureSettings.getSampleRate(),

NUM_CHANNELS_CAPTURING == 1 ? AudioFormat.CHANNEL_IN_MONO : AudioFormat.CHANNEL_IN_STEREO,

AudioFormat.ENCODING_PCM_16BIT

);

// double size to be more safe

int recBufSize = minRecBufSize * 2;

// release the object

if (noiseSuppressor != null) {

noiseSuppressor.release();

noiseSuppressor = null;

}

if (echoCanceler != null) {

echoCanceler.release();

echoCanceler = null;

}

if (audioRecord != null) {

audioRecord.release();

audioRecord = null;

}

try {

audioRecord = new AudioRecord(AudioSource.VOICE_COMMUNICATION,

captureSettings.getSampleRate(),

NUM_CHANNELS_CAPTURING == 1 ? AudioFormat.CHANNEL_IN_MONO

: AudioFormat.CHANNEL_IN_STEREO,

AudioFormat.ENCODING_PCM_16BIT, recBufSize);

if (NoiseSuppressor.isAvailable()) {

noiseSuppressor = NoiseSuppressor.create(audioRecord.getAudioSessionId());

}

if (AcousticEchoCanceler.isAvailable()) {

echoCanceler = AcousticEchoCanceler.create(audioRecord.getAudioSessionId());

}

} catch (Exception e) {

throw new RuntimeException(e.getMessage());

}

// check that the audioRecord is ready to be used

if (audioRecord.getState() != AudioRecord.STATE_INITIALIZED) {

throw new RuntimeException("Audio capture is not initialized " + captureSettings.getSampleRate());

}

shutdownCaptureThread = false;

new Thread(captureThread).start();

return true;

}