Develop Reference

Crash when calls AudioTrack multiple times

I am working with Visualizer. It will get data from AudioTrack and display when I click a button. In the button, I will call the function DrawStart as below:
private void DrawStart() {
if (startDrawing) {
initRecorder();
mVisualizerView.link(track);
startRecording();
}
else {
DrawStop();
}
}
It works well for about 10 first click. That means if I call DrawStart more than 10 times it has error
Fatal signal 11 (SIGSEGV) at 0x00030000 (code=1), thread 8164 (Visualizer)
Could you help me to fix it? Thanks so much. There are my sub-fuctions
private void initRecorder() {
_audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
int maxJitter = AudioTrack.getMinBufferSize(SAMPLE_RATE, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT);
track = new AudioTrack(AudioManager.MODE_IN_COMMUNICATION, SAMPLE_RATE, AudioFormat.CHANNEL_OUT_MONO,
AudioFormat.ENCODING_PCM_16BIT, maxJitter, AudioTrack.MODE_STREAM);
_audioManager.startBluetoothSco();
_audioManager.setMode(AudioManager.STREAM_VOICE_CALL);
}
private void startRecording() {
recordingThread = new AudioRecordingThread(track,mRecorder, bufferSize,SAMPLE_RATE,new AudioRecordingHandler() {
// Do something
});
recordingThread.start();
}
private void DrawStop() {
if (recordingThread != null) {
recordingThread = null;
}
track.release();
startDrawing = true;
}
And
public void link(AudioTrack player)
{
if(player == null)
{
throw new NullPointerException("Cannot link to null MediaPlayer");
}
int playerId=player.getAudioSessionId();
// Create the Visualizer object and attach it to our media player.
mVisualizer = new Visualizer(playerId);
mVisualizer.setScalingMode(Visualizer.SCALING_MODE_NORMALIZED);
mVisualizer.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
}

It was fixed by setting the application's hardwareAccelerated attribute to false in AndroidManifest.xml
<application
android:hardwareAccelerated="false"

AudioRecord: Continuously record audio data and simultaneously analyse it

I am trying to use an AudioRecord object in android to record audio data into a byte array and simultaneously perform some analysis on the recorded data. But I am unsure how to do it.
If I use the byte array directly the application crashes. I need a byte array as an input for the analysing thread I am relatively new to android development and I would appreciate any help on this topic.
Thanks
byte[] data;
public void Record()throws IOException{
int bufferSize = AudioRecord.getMinBufferSize(RECORDER_SAMPLERATE,RECORDER_CHANNELS,RECORDER_AUDIO_ENCODING);
AudioRecord recorder = new AudioRecord(MediaRecorder.AudioSource.MIC,
RECORDER_SAMPLERATE, RECORDER_CHANNELS,RECORDER_AUDIO_ENCODING, bufferSize);
recorder.startRecording();
isRecording = true;
boolean flag = true;
data = new byte[bufferSize];
while(isRecording){
try {
int result = recorder.read(data, 0, bufferSize);
if(flag){
Thread analyseThread = new Thread(new Runnable() {
#Override
public void run() {
theAnalysingFunction();
}
},"AudioRecorder Thread");
analyseThread.start();
flag=false;
}
if (AudioRecord.ERROR_INVALID_OPERATION !=result ) {
} else if (result == AudioRecord.ERROR_INVALID_OPERATION) {
Log.e("Recording", "Invalid operation error");
break;
} else if (result == AudioRecord.ERROR_BAD_VALUE) {
Log.e("Recording", "Bad value error");
break;
} else if (result == AudioRecord.ERROR) {
Log.e("Recording", "Unknown error");
break;
}
} catch (Exception e) {
Log.i("Error", "AudioRecord error");
}
}
}
public void theAnalysingFunction(){
//
//Analyse the byte array named data
//
}

This is multithreading. You try to analyze a buffer. While another thread changes it simultaneously.
About your crash, if U use a byte buffer, make sure U use ENCODING_PCM_8BIT for encoding.

Media Player using AudioTrack class does not resume after pause()

I'm building, inside my existing app, a player using the AudioTrack class,in MODE_STATIC, because i want to implement the timestretch and the loop points features.
The code is ok for start() and stop(), but when paused, if i try to resume, calling play() again, the status bar remain fixed and no audio is played.
Now, from the docs :
Public void pause ()Pauses the playback of the audio data. Data that has not been played >back will not be discarded. Subsequent calls to play() will play this data back. See >flush() to discard this data.
It seems so easy to understand but there is something that escapes me.
Can some one help me?
Is it necessary to create boolean variables like start, play, pause, stopAudio etc?
If yes, where is the utility of the methods inherited from the AudioTrack class?
In MODE_STREAM i have realized the project, using the above boolean variables., but i need the MODE_STATIC.
This is the code, thanks:
Button playpause, stop;
SeekBar posBar;
int sliderval=0;
int headerOffset = 0x2C;
File file =new File(Environment.getExternalStorageDirectory(), "raw.pcm");
int fileSize = (int) file.length();
int dataSize = fileSize-headerOffset ;
byte[] dataArray = new byte[dataSize];
int posValue;
int dataBytesRead = initializeTrack();
AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, 44100,
AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT, dataBytesRead , AudioTrack.MODE_STATIC);
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
playpause= (Button)(findViewById(R.id.playpause));
stop= (Button)(findViewById(R.id.stop));
posBar=(SeekBar)findViewById(R.id.posBar);
// create a listener for the slider bar;
OnSeekBarChangeListener listener = new OnSeekBarChangeListener() {
public void onStopTrackingTouch(SeekBar seekBar) { }
public void onStartTrackingTouch(SeekBar seekBar) { }
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
if (fromUser) { sliderval = progress;}
}
};
// set the listener on the slider
posBar.setOnSeekBarChangeListener(listener); }
public void toggleButtonSound(View button)
{
switch (button.getId())
{
case R.id.playpause:
play();
break;
case R.id.stop:
stop();
break;
}
}
private void stop() {
if(audioTrack.getState()==AudioTrack.PLAYSTATE_PLAYING ||
audioTrack.getState()==AudioTrack.PLAYSTATE_PAUSED || audioTrack.getState()==AudioTrack.PLAYSTATE_STOPPED)
{ audioTrack.stop();
resetPlayer();}
}
Context context;
private double actualPos=0;
public void pause() {}
public void play()
{
if (audioTrack.getPlayState()==AudioTrack.PLAYSTATE_PLAYING)
{ //Log.i("", "Play pressed in state "+audioTrack.getPlayState());
audioTrack.pause();
}
else if (audioTrack.getPlayState()==AudioTrack.PLAYSTATE_PAUSED)
{ //Log.i("", "Play pressed in state "+audioTrack.getPlayState());
audioTrack.play();
}
else if (audioTrack.getPlayState()==AudioTrack.PLAYSTATE_STOPPED)
{ //Log.i("", "Play pressed in state "+audioTrack.getPlayState());
audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, 44100, AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT, dataSize, AudioTrack.MODE_STATIC);
audioTrack.write(dataArray, 0, dataBytesRead);
audioTrack.play();
}
posBar.setMax((int) (dataBytesRead/2)); // Set the Maximum range of the
audioTrack.setNotificationMarkerPosition((int) (dataSize/2));
audioTrack.setPositionNotificationPeriod(1000);
audioTrack.setPlaybackPositionUpdateListener(new OnPlaybackPositionUpdateListener() {
#Override
public void onPeriodicNotification(AudioTrack track) {
posBar.setProgress(audioTrack.getPlaybackHeadPosition());
Log.i("", " " + audioTrack.getPlaybackHeadPosition() + " " + dataBytesRead/2);
}
#Override
public void onMarkerReached(AudioTrack track) {
Log.i("", " End reached ");
audioTrack.pause();
audioTrack.flush();
audioTrack.release();
posBar.setProgress(0);
resetPlayer();}
});
}
private int initializeTrack() {
InputStream is;
BufferedInputStream bis;
DataInputStream dis;
int temp = 0;
try {
is = new FileInputStream(file);
bis = new BufferedInputStream(is);
dis = new DataInputStream(bis);
temp = dis.read(dataArray, 0, dataSize);
dis.close();
bis.close();
is.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return temp;
}
public void resetPlayer() {
audioTrack.flush();
audioTrack.release();
posBar.setProgress(0);
sliderval=0;
}

You see, you did implement AudioTrack so that even when its paused the contents of file still uploads to AudioTrack:
I don't know how it manage it but in my case I also pause data uploading to AT. Like:
while (byteOffset < fileLengh) {
if(isPaused)
continue;
ret = in.read(byteData, 0, byteCount);
if (ret != -1) { // Write the byte array to the track
audioTrack.write(byteData, 0, ret);
byteOffset += ret;
} else
break;
}
So then I unpause the AT the file uploading while cycle resumes too. I guess that's it. Also I have to mention that even when AT is playing the following:
if (audioTrack.getPlayState()==AudioTrack.PLAYSTATE_PLAYING)
and
if (audioTrack.getPlayState()==AudioTrack.PLAYSTATE_PAUSED)
doesn't work for me and getPlayState() always returns 1 (AudioTrack.PLAYSTATE_STOPPED) for me, no matter if its playing or has been paused.

How exactly does the AudioRecord class work?

Please see my other questions as well because I think they are related:
Question 1
Question 2
Question 3
This is the code I am using which performs a pass through of the audio signals obtained at the mic to the speaker, when I press a buton:
public class MainActivity extends Activity {
AudioManager am = null;
AudioRecord record =null;
AudioTrack track =null;
final int SAMPLE_FREQUENCY = 44100;
final int SIZE_OF_RECORD_ARRAY = 1024; // 1024 ORIGINAL
final int WAV_SAMPLE_MULTIPLICATION_FACTOR = 1;
int i= 0;
boolean isPlaying = false;
private volatile boolean keepThreadRunning;
private RandomAccessFile stateFile, stateFileTemp;
private File delFile, renFile;
String stateFileLoc = Environment.getExternalStorageDirectory().getPath();
class MyThread extends Thread{
private volatile boolean needsToPassThrough;
// /*
MyThread(){
super();
}
MyThread(boolean newPTV){
this.needsToPassThrough = newPTV;
}
// */
// /*
#Override
public void run(){
// short[] lin = new short[SIZE_OF_RECORD_ARRAY];
byte[] lin = new byte[SIZE_OF_RECORD_ARRAY];
int num = 0;
// /*
if(needsToPassThrough){
record.startRecording();
track.play();
}
// */
while (keepThreadRunning) {
// while (!isInterrupted()) {
num = record.read(lin, 0, SIZE_OF_RECORD_ARRAY);
for(i=0;i<lin.length;i++)
lin[i] *= WAV_SAMPLE_MULTIPLICATION_FACTOR;
track.write(lin, 0, num);
}
// /*
record.stop();
track.stop();
record.release();
track.release();
// */
}
// */
// /*
public void stopThread(){
keepThreadRunning = false;
}
// */
}
MyThread newThread;
private void init() {
int min = AudioRecord.getMinBufferSize(SAMPLE_FREQUENCY, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);
record = new AudioRecord(MediaRecorder.AudioSource.VOICE_COMMUNICATION, SAMPLE_FREQUENCY, AudioFormat.CHANNEL_IN_MONO,
AudioFormat.ENCODING_PCM_16BIT, min);
int maxJitter = AudioTrack.getMinBufferSize(SAMPLE_FREQUENCY, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT);
track = new AudioTrack(AudioManager.MODE_IN_COMMUNICATION, SAMPLE_FREQUENCY, AudioFormat.CHANNEL_OUT_MONO,
AudioFormat.ENCODING_PCM_16BIT, maxJitter, AudioTrack.MODE_STREAM);
am = (AudioManager) this.getSystemService(Context.AUDIO_SERVICE);
am.setMode(AudioManager.MODE_IN_COMMUNICATION);
try {
stateFile = new RandomAccessFile(stateFileLoc+"/appState.txt", "rwd");
stateFileTemp = new RandomAccessFile(stateFileLoc+"/appStateTemp.txt", "rwd");
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
delFile = new File(stateFileLoc+"/appState.txt");
renFile = new File(stateFileLoc+"/appStateTemp.txt");
}
#Override
protected void onResume(){
super.onResume();
// newThread.stopThread();
Log.d("MYLOG", "onResume() called");
init();
keepThreadRunning = true;
try {
if(stateFile.readInt() == 1){
isPlaying = true;
Log.d("MYLOG", "readInt == 1");
}
else{
isPlaying = false;
Log.d("MYLOG", "readInt <> 1");
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// */
// newThread = new MyThread(true);
newThread = new MyThread(isPlaying);
newThread.start();
}
#Override
protected void onPause(){
super.onPause();
Log.d("MYLOG", "onPause() called");
newThread.stopThread();
// android.os.Process.killProcess(android.os.Process.myPid());
try {
if(isPlaying)
stateFileTemp.writeInt(1);
else
stateFileTemp.writeInt(0);
delFile.delete();
renFile.renameTo(delFile);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setVolumeControlStream(AudioManager.MODE_IN_COMMUNICATION);
Log.d("MYLOG","onCreate() called");
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
protected void onDestroy() {
super.onDestroy();
newThread.stopThread();
// android.os.Process.killProcess(android.os.Process.myPid());
// killProcess(android.os.Process.myPid());
// newThread.interrupt();
delFile.delete();
Log.d("MYLOG", "onDestroy() called");
}
public void passStop(View view){
Button playBtn = (Button) findViewById(R.id.button1);
// /*
if(!isPlaying){
record.startRecording();
track.play();
isPlaying = true;
playBtn.setText("Pause");
}
else{
record.stop();
track.pause();
isPlaying=false;
playBtn.setText("Pass through");
}
// */
}
the files appState.txt and appStateTemp.txt were added to save whether pass through was being performed when the app last lost focus, but that is probably not very significant here. What I want to know is:
What happens when record.read() is called without calling record.startrecording() ?
What is the significance of SIZE_OF_RECORD_ARRAY? I thought it should be at least the value returned by AudioRecord.getMinBufferSize() but in this program it doesn't affect the output at all even if I set it to 1.
If I use 16 bit PCM encoding I need at least a short variable to store the digital equivalent of the audio samples. However in this code even if I change the lin variable from short array to byte array, there is no apparent change in the output. So how does the read function store the digital samples in the array? Does it automatically allocate 2 byte elements for each sample? If that is the case, does it do it as little endian or big endian?

Question 1 and 3 should be easy for you to check with your app, but here goes:
1: What happens when record.read() is called without calling record.startrecording() ?
I would expect there to be no flow of data from the underlying audio input stream, and that read() therefore returns 0 or possibly an error code, indicating that no data has been read.
2: What is the significance of SIZE_OF_RECORD_ARRAY? I thought it should be at least the value returned by AudioRecord.getMinBufferSize() but in this program it doesn't affect the output at all even if I set it to 1.
The value of getMinBufferSize is important when you specify the buffer size in the call to the AudioRecord constructor. What you're changing with SIZE_OF_RECORD_ARRAY is just the amount of data you're reading with each call to read() - and while it isn't a particularly good idea to call read() once per byte (because of the overhead of all those function calls), I can imagine that it still will work.
3: If I use 16 bit PCM encoding I need at least a short variable to store the digital equivalent of the audio samples. However in this code even if I change the lin variable from short array to byte array, there is no apparent change in the output. So how does the read function store the digital samples in the array? Does it automatically allocate 2 byte elements for each sample? If that is the case, does it do it as little endian or big endian?
The underlying native code always uses the byte version. The short version is simply a wrapper around the byte version. So yes, a pair of bytes will be used for each sample in this case.
As for the endianness; it would be little-endian on the vast majority of Android devices out there.

Try this I hope will work 100%
MediaRecorder mRecorder = null;
String mFileName;
private void startRecording() {
try {
mRecorder = new MediaRecorder();
mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mFileName = getRecordDefaultFileName();
mRecorder.setOutputFile(mFileName);
mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
try {
mRecorder.prepare();
} catch (IOException e) {
System.out.println("prepare() failed");
}
mRecorder.start();
} catch (Exception e) {
return;
}
}
private void stopRecording() {
try {
if (mRecorder != null) {
mRecorder.stop();
mRecorder.release();
mRecorder = null;
}
} catch (Exception e) {
}
}
private String getRecordDefaultFileName() {
File wallpaperDirectory = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/" + "recordingFolder" + "/");
if (!wallpaperDirectory.exists()) {
wallpaperDirectory.mkdirs();
}
return wallpaperDirectory.getAbsolutePath() + File.separator + "iarecord" + ".3gp";
}

Recognize Stop AudioTrack

How to detect if an AudioTrack has finished playing? it's not simple!!!
I need to touch immediately after the other (enqueue) This code is not working ...
When press 2 times, the 1st not end, and two sound plays same time...
private void getNextAudio() {
try{
byte[] buffer = playlist.poll();
if (buffer != null) {
AudioTrack myatrack = getAudioTrack(buffer);
myatrack.setPlaybackPositionUpdateListener( new OnPlaybackPositionUpdateListener() {
public void onPeriodicNotification(AudioTrack track) {
}
public void onMarkerReached(AudioTrack track) {
Log.d(TAG, "onMarker - estado: " + track.getPlayState());
if(track.getPlayState() == AudioTrack.PLAYSTATE_STOPPED){
track.flush();
track.stop();
track.release();
getNextAudio();
}
}
});
if (myatrack != null) {
// toco o audio.
myatrack.play();
}
}else{
Log.d(TAG,"Finish");
}
}catch(NoSuchElementException ex){
Log.d(TAG,"No such element");
}
}
Thanks again!
Mateus