Develop Reference

Audio Recording and Streaming in Android

I an developing an android app. I want to accomplish below feature.
I will use my phone's built-in mic to record and at the same time i want the recorded audio to be played through either phone's speakers or headphones.
Is it feasible? If yes, please help me in this.

Here is a simple Recording and Playback application.
Uses Android AudioRecord and AudioTrack,
Design:
The recorded audio is written to a buffer and played back from the same buffer, This mechanism runs in a loop (using Android thread) controlled by buttons.
Code
private String TAG = "AUDIO_RECORD_PLAYBACK";
private boolean isRunning = true;
private Thread m_thread; /* Thread for running the Loop */
private AudioRecord recorder = null;
private AudioTrack track = null;
int bufferSize = 320; /* Buffer for recording data */
byte buffer[] = new byte[bufferSize];
/* Method to Enable/Disable Buttons */
private void enableButton(int id,boolean isEnable){
((Button)findViewById(id)).setEnabled(isEnable);
}
The GUI has two Buttons START and STOP.
Enable the Button:
enableButton(R.id.StartButton,true);
enableButton(R.id.StopButton,false);
/* Assign Button Click Handlers */
((Button)findViewById(R.id.StartButton)).setOnClickListener(btnClick);
((Button)findViewById(R.id.StopButton)).setOnClickListener(btnClick);
Mapping START and STOP Button for OnClickListener
private View.OnClickListener btnClick = new View.OnClickListener() {
#Override
public void onClick(View v) {
switch(v.getId()){
case R.id.StartButton:
{
Log.d(TAG, "======== Start Button Pressed ==========");
isRunning = true;
do_loopback(isRunning);
enableButton(R.id.StartButton,false);
enableButton(R.id.StopButton,true);
break;
}
case R.id.StopButton:
{
Log.d(TAG, "======== Stop Button Pressed ==========");
isRunning = false;
do_loopback(isRunning);
enableButton(R.id.StopButton,false);
enableButton(R.id.StartButton,true);
break;
}
}
}
Start the Thread:
private void do_loopback(final boolean flag)
{
m_thread = new Thread(new Runnable() {
public void run() {
run_loop(flag);
}
});
m_thread.start();
}
Method for Initializing AudioRecord and AudioTrack:
public AudioTrack findAudioTrack (AudioTrack track)
{
Log.d(TAG, "===== Initializing AudioTrack API ====");
int m_bufferSize = AudioTrack.getMinBufferSize(8000,
AudioFormat.CHANNEL_OUT_MONO,
AudioFormat.ENCODING_PCM_16BIT);
if (m_bufferSize != AudioTrack.ERROR_BAD_VALUE)
{
track = new AudioTrack(AudioManager.STREAM_MUSIC, 8000,
AudioFormat.CHANNEL_OUT_MONO,
AudioFormat.ENCODING_PCM_16BIT, m_bufferSize,
AudioTrack.MODE_STREAM);
if (track.getState() == AudioTrack.STATE_UNINITIALIZED) {
Log.e(TAG, "===== AudioTrack Uninitialized =====");
return null;
}
}
return track;
}
public AudioRecord findAudioRecord (AudioRecord recorder)
{
Log.d(TAG, "===== Initializing AudioRecord API =====");
int m_bufferSize = AudioRecord.getMinBufferSize(8000,
AudioFormat.CHANNEL_IN_MONO,
AudioFormat.ENCODING_PCM_16BIT);
if (m_bufferSize != AudioRecord.ERROR_BAD_VALUE)
{
recorder = new AudioRecord(MediaRecorder.AudioSource.MIC, 8000,
AudioFormat.CHANNEL_IN_MONO,
AudioFormat.ENCODING_PCM_16BIT, m_bufferSize);
if (recorder.getState() == AudioRecord.STATE_UNINITIALIZED) {
Log.e(TAG, "====== AudioRecord UnInitilaised ====== ");
return null;
}
}
return recorder;
}
The Values for findAudioRecord or findAudioTrack can change based on device.
Please refer this question.
Code for Running the loop:
public void run_loop (boolean isRunning)
{
/** == If Stop Button is pressed == **/
if (isRunning == false) {
Log.d(TAG, "===== Stop Button is pressed ===== ");
if (AudioRecord.STATE_INITIALIZED == recorder.getState()){
recorder.stop();
recorder.release();
}
if (AudioTrack.STATE_INITIALIZED == track.getState()){
track.stop();
track.release();
}
return;
}
/** ======= Initialize AudioRecord and AudioTrack ======== **/
recorder = findAudioRecord(recorder);
if (recorder == null) {
Log.e(TAG, "======== findAudioRecord : Returned Error! =========== ");
return;
}
track = findAudioTrack(track);
if (track == null) {
Log.e(TAG, "======== findAudioTrack : Returned Error! ========== ");
return;
}
if ((AudioRecord.STATE_INITIALIZED == recorder.getState()) &&
(AudioTrack.STATE_INITIALIZED == track.getState()))
{
recorder.startRecording();
Log.d(TAG, "========= Recorder Started... =========");
track.play();
Log.d(TAG, "========= Track Started... =========");
}
else
{
Log.d(TAG, "==== Initilazation failed for AudioRecord or AudioTrack =====");
return;
}
/** ------------------------------------------------------ **/
/* Recording and Playing in chunks of 320 bytes */
bufferSize = 320;
while (isRunning == true)
{
/* Read & Write to the Device */
recorder.read(buffer, 0, bufferSize);
track.write(buffer, 0, bufferSize);
}
Log.i(TAG, "Loopback exit");
return;
}
Please include the following in AndroidManifest.xml
<uses-permission android:name="android.permission.RECORD_AUDIO" > </uses-permission>
This above procedure is also possible by Writing/Reading from a file using the same APIs.
Why use audioRecord over mediaRecorder - See here.
The Code is tested (on Google Nexus 5) and working perfectly.
Note: Please add some error-checking code for recorder.read and track.write, in case you fail. Same applies for findAudioRecord and findAudioTrack.

First create objects in onCreate method, MediaRecorder class object and the path to file where you want to save the recorded data.
String outputFile = Environment.getExternalStorageDirectory().
getAbsolutePath() + "/myrecording.3gp"; // Define outputFile outside onCreate method
MediaRecorder myAudioRecorder = new MediaRecorder(); // Define this outside onCreate method
myAudioRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
myAudioRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
myAudioRecorder.setAudioEncoder(MediaRecorder.OutputFormat.AMR_NB);
myAudioRecorder.setOutputFile(outputFile);
These three function you can call it on any button, in order to play Rec, stop Rec and start Rec;
public void start(View view){
try {
myAudioRecorder.prepare();
myAudioRecorder.start();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
start.setEnabled(false);
stop.setEnabled(true);
Toast.makeText(getApplicationContext(), "Recording started", Toast.LENGTH_LONG).show();
}
public void stop(View view){
myAudioRecorder.stop();
myAudioRecorder.release();
myAudioRecorder = null;
stop.setEnabled(false);
play.setEnabled(true);
Toast.makeText(getApplicationContext(), "Audio recorded successfully",
Toast.LENGTH_LONG).show();
}
public void play(View view) throws IllegalArgumentException,
SecurityException, IllegalStateException, IOException{
MediaPlayer m = new MediaPlayer();
m.setDataSource(outputFile);
m.prepare();
m.start();
Toast.makeText(getApplicationContext(), "Playing audio", Toast.LENGTH_LONG).show();
}

As I read Developer document here , Android supports RTSP protocol (for real time streaming) and also HTTP/HTTPS live streaming draft protocol.
There is also an example here. You must have base knowledge about Streaming server, like Red5 or Wowza.

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";
}

Recording with AudioRecord on Android speeds up the audio?

I am using AudioRecord to record raw audio for processing.
The audio records entirely without any noise but when the raw PCM data generated is played back, it plays as if it has been speeded up a lot (upto about twice as much).
I am viewing and playing the PCM data in Audacity. I am using actual phone (Samsung Galaxy S5670) for testing.
The recording is done at 44100 Hz, 16 bit. Any idea what might cause this?
Following is the recording code:
public class TestApp extends Activity
{
File file;
OutputStream os;
BufferedOutputStream bos;
AudioRecord recorder;
int iAudioBufferSize;
boolean bRecording;
int iBytesRead;
Thread recordThread = new Thread(){
#Override
public void run()
{
byte[] buffer = new byte[iAudioBufferSize];
int iBufferReadResult;
iBytesRead = 0;
while(!interrupted())
{
iBufferReadResult = recorder.read(buffer, 0, iAudioBufferSize);
// Android is reading less number of bytes than requested.
if(iAudioBufferSize > iBufferReadResult)
{
iBufferReadResult = iBufferReadResult +
recorder.read(buffer, iBufferReadResult - 1, iAudioBufferSize - iBufferReadResult);
}
iBytesRead = iBytesRead + iBufferReadResult;
for (int i = 0; i < iBufferReadResult; i++)
{
try
{
bos.write(buffer[i]);
} catch (IOException e)
{
e.printStackTrace();
}
}
}
}
};
#Override
public void onCreate(Bundle savedInstanceState)
{
// File Creation and UI init stuff etc.
bRecording = false;
bPlaying = false;
int iSampleRate = AudioTrack.getNativeOutputSampleRate(AudioManager.STREAM_SYSTEM);
iAudioBufferSize = AudioRecord.getMinBufferSize(iSampleRate, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);
recorder = new AudioRecord(AudioSource.MIC, iSampleRate, AudioFormat.CHANNEL_IN_MONO,
AudioFormat.ENCODING_PCM_16BIT, iAudioBufferSize);
bt_Record.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v)
{
if (!bRecording)
{
try
{
recorder.startRecording();
bRecording = true;
recordThread.start();
}
catch(Exception e)
{
tv_Error.setText(e.getLocalizedMessage());
}
}
else
{
recorder.stop();
bRecording = false;
recordThread.interrupt();
try
{
bos.close();
}
catch(IOException e)
{
}
tv_Hello.setText("Recorded Sucessfully. Total " + iBytesRead + " bytes.");
}
}
});
}
}
RESOLVED : I posted this after struggling with it for 1-2 days. But, ironically, I found the solution soon after posting. The buffered output stream write was taking too much time in the for loop, so the stream was skipping samples. changed it to block write, removing the for loop. Works perfectly.

The audio skipping was caused by the delay in writing to buffer.
the solution is to just replace this FOR loop:
for (int i = 0; i < iBufferReadResult; i++)
{
try
{
bos.write(buffer[i]);
} catch (IOException e)
{
e.printStackTrace();
}
}
by a single write, like so:
bos.write(buffer, 0, iBufferReadResult);
I had used the code from a book which worked, I guess, for lower sample rates and buffer updates.

Live streaming in android

I need to play a live stream video. I am trying to play the video by using MediaPlayer & SurfaceView. The URL is redirected from http with .mov to rtsp with .3gp extension. Vide plays efficiently in OS v2.3.x, but it does not play in any other OS version from 2.1 onward. Any suggestions?

public class StreamingAudioActivity extends Activity {
/** Called when the activity is first created. */
private Button streamButton;
private ImageButton playButton;
private TextView textStreamed;
private boolean isPlaying;
private StreamingMediaPlayer audioStreamer;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// }
//
// private void initControls() {
textStreamed = (TextView) findViewById(R.id.text_kb_streamed);
streamButton = (Button) findViewById(R.id.button_stream);
streamButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Log.v("click","streaming on");
startStreamingAudio();
}
});
playButton = (ImageButton) findViewById(R.id.button_play);
playButton.setEnabled(false);
playButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
if (audioStreamer.getMediaPlayer().isPlaying()) {
audioStreamer.getMediaPlayer().pause();
playButton.setImageResource(R.drawable.button_play);
} else {
audioStreamer.getMediaPlayer().start();
audioStreamer.startPlayProgressUpdater();
playButton.setImageResource(R.drawable.button_pause);
}
isPlaying = !isPlaying;
}
});
}
private void startStreamingAudio() {
try {
final ProgressBar progressBar = (ProgressBar) findViewById(R.id.progress_bar);
if (audioStreamer != null) {
audioStreamer.interrupt();
}
audioStreamer = new StreamingMediaPlayer(this, textStreamed,
playButton, streamButton, progressBar);
Log.v("aaa", "sdaa");
// audioStreamer.startStreaming("http://www.pocketjourney.com/downloads/pj/tutorials/audio.mp3",1717,
// 214);
audioStreamer.startStreaming(
"http://vprbbc.streamguys.net:80/vprbbc24.mp3",
1717, 216);
// http://rkmania.me/playlistAction.php?action=addTrack&trck=115976
streamButton.setEnabled(false);
} catch (IOException e) {
Log.e(getClass().getName(), "Error starting to stream audio.", e);
}
}
public class StreamingMediaPlayer {
private static final int INTIAL_KB_BUFFER = 96*10/8;//assume 96kbps*10secs/8bits per byte
private TextView textStreamed;
private ImageButton playButton;
private ProgressBar progressBar;
// Track for display by progressBar
private long mediaLengthInKb, mediaLengthInSeconds;
private int totalKbRead = 0;
// Create Handler to call View updates on the main UI thread.
private final Handler handler = new Handler();
private MediaPlayer mediaPlayer;
private File downloadingMediaFile;
private boolean isInterrupted;
private Context context;
private int counter = 0;
public StreamingMediaPlayer(Context context,TextView textStreamed, ImageButton playButton, Button streamButton,ProgressBar progressBar)
{
this.context = context;
this.textStreamed = textStreamed;
this.playButton = playButton;
this.progressBar = progressBar;
}
/**
* Progressivly download the media to a temporary location and update the MediaPlayer as new content becomes available.
*/
public void startStreaming(final String mediaUrl, long mediaLengthInKb, long mediaLengthInSeconds) throws IOException {
this.mediaLengthInKb = mediaLengthInKb;
this.mediaLengthInSeconds = mediaLengthInSeconds;
Runnable r = new Runnable() {
public void run() {
try {
downloadAudioIncrement(mediaUrl);
} catch (IOException e) {
Log.e(getClass().getName(), "Unable to initialize the MediaPlayer for fileUrl=" + mediaUrl, e);
return;
}
}
};
new Thread(r).start();
}
/**
* Download the url stream to a temporary location and then call the setDataSource
* for that local file
*/
public void downloadAudioIncrement(String mediaUrl) throws IOException {
URLConnection cn = new URL(mediaUrl).openConnection();
cn.connect();
InputStream stream = cn.getInputStream();
if (stream == null) {
Log.e(getClass().getName(), "Unable to create InputStream for mediaUrl:" + mediaUrl);
}
downloadingMediaFile = new File(context.getCacheDir(),"downloadingMedia.dat");
// Just in case a prior deletion failed because our code crashed or something, we also delete any previously
// downloaded file to ensure we start fresh. If you use this code, always delete
// no longer used downloads else you'll quickly fill up your hard disk memory. Of course, you can also
// store any previously downloaded file in a separate data cache for instant replay if you wanted as well.
if (downloadingMediaFile.exists()) {
downloadingMediaFile.delete();
}
FileOutputStream out = new FileOutputStream(downloadingMediaFile);
byte buf[] = new byte[16384];
int totalBytesRead = 0, incrementalBytesRead = 0;
do {
int numread = stream.read(buf);
if (numread <= 0)
break;
out.write(buf, 0, numread);
totalBytesRead += numread;
incrementalBytesRead += numread;
totalKbRead = totalBytesRead/1000;
testMediaBuffer();
fireDataLoadUpdate();
} while (validateNotInterrupted());
stream.close();
if (validateNotInterrupted()) {
fireDataFullyLoaded();
}
}
private boolean validateNotInterrupted() {
if (isInterrupted) {
if (mediaPlayer != null) {
mediaPlayer.pause();
//mediaPlayer.release();
}
return false;
} else {
return true;
}
}
/**
* Test whether we need to transfer buffered data to the MediaPlayer.
* Interacting with MediaPlayer on non-main UI thread can causes crashes to so perform this using a Handler.
*/
private void testMediaBuffer() {
Runnable updater = new Runnable() {
public void run() {
if (mediaPlayer == null) {
// Only create the MediaPlayer once we have the minimum buffered data
if ( totalKbRead >= INTIAL_KB_BUFFER) {
try {
startMediaPlayer();
} catch (Exception e) {
Log.e(getClass().getName(), "Error copying buffered conent.", e);
}
}
} else if ( mediaPlayer.getDuration() - mediaPlayer.getCurrentPosition() <= 1000 ){
// NOTE: The media player has stopped at the end so transfer any existing buffered data
// We test for < 1second of data because the media player can stop when there is still
// a few milliseconds of data left to play
transferBufferToMediaPlayer();
}
}
};
handler.post(updater);
}
private void startMediaPlayer() {
try {
File bufferedFile = new File(context.getCacheDir(),"playingMedia" + (counter++) + ".dat");
// We double buffer the data to avoid potential read/write errors that could happen if the
// download thread attempted to write at the same time the MediaPlayer was trying to read.
// For example, we can't guarantee that the MediaPlayer won't open a file for playing and leave it locked while
// the media is playing. This would permanently deadlock the file download. To avoid such a deadloack,
// we move the currently loaded data to a temporary buffer file that we start playing while the remaining
// data downloads.
moveFile(downloadingMediaFile,bufferedFile);
Log.e(getClass().getName(),"Buffered File path: " + bufferedFile.getAbsolutePath());
Log.e(getClass().getName(),"Buffered File length: " + bufferedFile.length()+"");
mediaPlayer = createMediaPlayer(bufferedFile);
// We have pre-loaded enough content and started the MediaPlayer so update the buttons & progress meters.
mediaPlayer.start();
startPlayProgressUpdater();
playButton.setEnabled(true);
} catch (IOException e) {
Log.e(getClass().getName(), "Error initializing the MediaPlayer.", e);
return;
}
}
private MediaPlayer createMediaPlayer(File mediaFile)
throws IOException {
MediaPlayer mPlayer = new MediaPlayer();
mPlayer.setOnErrorListener(
new MediaPlayer.OnErrorListener() {
public boolean onError(MediaPlayer mp, int what, int extra) {
Log.e(getClass().getName(), "Error in MediaPlayer: (" + what +") with extra (" +extra +")" );
return false;
}
});
// It appears that for security/permission reasons, it is better to pass a FileDescriptor rather than a direct path to the File.
// Also I have seen errors such as "PVMFErrNotSupported" and "Prepare failed.: status=0x1" if a file path String is passed to
// setDataSource(). So unless otherwise noted, we use a FileDescriptor here.
FileInputStream fis = new FileInputStream(mediaFile);
mPlayer.setDataSource(fis.getFD());
mPlayer.prepare();
return mPlayer;
}
/**
* Transfer buffered data to the MediaPlayer.
* NOTE: Interacting with a MediaPlayer on a non-main UI thread can cause thread-lock and crashes so
* this method should always be called using a Handler.
*/
private void transferBufferToMediaPlayer() {
try {
// First determine if we need to restart the player after transferring data...e.g. perhaps the user pressed pause
boolean wasPlaying = mediaPlayer.isPlaying();
int curPosition = mediaPlayer.getCurrentPosition();
// Copy the currently downloaded content to a new buffered File. Store the old File for deleting later.
File oldBufferedFile = new File(context.getCacheDir(),"playingMedia" + counter + ".dat");
File bufferedFile = new File(context.getCacheDir(),"playingMedia" + (counter++) + ".dat");
// This may be the last buffered File so ask that it be delete on exit. If it's already deleted, then this won't mean anything. If you want to
// keep and track fully downloaded files for later use, write caching code and please send me a copy.
bufferedFile.deleteOnExit();
moveFile(downloadingMediaFile,bufferedFile);
// Pause the current player now as we are about to create and start a new one. So far (Android v1.5),
// this always happens so quickly that the user never realized we've stopped the player and started a new one
mediaPlayer.pause();
// Create a new MediaPlayer rather than try to re-prepare the prior one.
mediaPlayer = createMediaPlayer(bufferedFile);
mediaPlayer.seekTo(curPosition);
// Restart if at end of prior buffered content or mediaPlayer was previously playing.
// NOTE: We test for < 1second of data because the media player can stop when there is still
// a few milliseconds of data left to play
boolean atEndOfFile = mediaPlayer.getDuration() - mediaPlayer.getCurrentPosition() <= 1000;
if (wasPlaying || atEndOfFile){
mediaPlayer.start();
}
// Lastly delete the previously playing buffered File as it's no longer needed.
oldBufferedFile.delete();
}catch (Exception e) {
Log.e(getClass().getName(), "Error updating to newly loaded content.", e);
}
}
private void fireDataLoadUpdate() {
Runnable updater = new Runnable() {
public void run() {
textStreamed.setText((totalKbRead + " Kb read"));
float loadProgress = ((float)totalKbRead/(float)mediaLengthInKb);
progressBar.setSecondaryProgress((int)(loadProgress*100));
}
};
handler.post(updater);
}
private void fireDataFullyLoaded() {
Runnable updater = new Runnable() {
public void run() {
transferBufferToMediaPlayer();
// Delete the downloaded File as it's now been transferred to the currently playing buffer file.
downloadingMediaFile.delete();
textStreamed.setText(("Audio full loaded: " + totalKbRead + " Kb read"));
}
};
handler.post(updater);
}
public MediaPlayer getMediaPlayer() {
return mediaPlayer;
}
public void startPlayProgressUpdater() {
float progress = (((float)mediaPlayer.getCurrentPosition()/1000)/mediaLengthInSeconds);
progressBar.setProgress((int)(progress*100));
if (mediaPlayer.isPlaying()) {
Runnable notification = new Runnable() {
public void run() {
startPlayProgressUpdater();
}
};
handler.postDelayed(notification,1000);
}
}
public void interrupt() {
playButton.setEnabled(false);
isInterrupted = true;
validateNotInterrupted();
}
/**
* Move the file in oldLocation to newLocation.
*/
public void moveFile(File oldLocation, File newLocation)
throws IOException {
if ( oldLocation.exists( )) {
BufferedInputStream reader = new BufferedInputStream( new FileInputStream(oldLocation) );
BufferedOutputStream writer = new BufferedOutputStream( new FileOutputStream(newLocation, false));
try {
byte[] buff = new byte[8192];
int numChars;
while ( (numChars = reader.read( buff, 0, buff.length ) ) != -1) {
writer.write( buff, 0, numChars );
}
} catch( IOException ex ) {
throw new IOException("IOException when transferring " + oldLocation.getPath() + " to " + newLocation.getPath());
} finally {
try {
if ( reader != null ){
writer.close();
reader.close();
}
} catch( IOException ex ){
Log.e(getClass().getName(),"Error closing files when transferring " + oldLocation.getPath() + " to " + newLocation.getPath() );
}
}
} else {
throw new IOException("Old location does not exist when transferring " + oldLocation.getPath() + " to " + newLocation.getPath() );
}
}
}

Android How to set loop on AudioTrack?

I'm playing .wav files using AudioTrack.
I have a problem.
I set the setLoopPoints to loop my .wav files, but it doesn't work.
This is my sample code.
public class PleaseActivity extends Activity implements Runnable{
AudioTrack audioTrack;
public static final String MEDIA_PATH = Environment.getExternalStorageDirectory().getAbsolutePath()+"/TEST";
/** Called when the activity is first created. */
Button play_button, stop_button;
File file = null;
byte[] byteData = null;
Boolean playing = false;
int bufSize;
AudioTrack myAT = null;
Thread play_thread = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
play_button = (Button) findViewById(R.id.btn1);
stop_button = (Button) findViewById(R.id.btn2);
file = new File(MEDIA_PATH+"/untitled1.wav");
byteData = new byte[(int) file.length()];
FileInputStream in = null;
try {
in = new FileInputStream(file);
in.read(byteData);
in.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
initialize();
play_button.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
play_thread.start();
}
});
//
stop_button.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
//
if (myAT.getPlayState() == AudioTrack.PLAYSTATE_PLAYING) {
myAT.stop();
play_thread = null;
initialize();
}
}
});
}
void initialize() {
bufSize = android.media.AudioTrack.getMinBufferSize(44100,
AudioFormat.CHANNEL_CONFIGURATION_STEREO,
AudioFormat.ENCODING_PCM_16BIT);
myAT = new AudioTrack(AudioManager.STREAM_MUSIC,
44100, AudioFormat.CHANNEL_CONFIGURATION_STEREO,
AudioFormat.ENCODING_PCM_16BIT, bufSize,
AudioTrack.MODE_STREAM);
play_thread = new Thread(this);
}
public void run() {
if (myAT != null) {
myAT.play();
myAT.setLoopPoints(0, byteData.length, 2);
myAT.write(byteData, 0, byteData.length);
}
}
}
I can play my wave files well, but setLoopPoints doesn't work!
Anybody helps me..
I solved this looping problems like this.
I have another problem.
whenever I wrote data into audiotrack,
I mean whenever audiotrack is repeated, some noise like "tick" is added at the first part.
I don't know how to eliminate this noise..
Is there anybody knows how to solve it?
class DLThread extends Thread
{
public void run()
{
while(!DLThread.interrupted())
{
if (myAT != null) {
//
myAT.play();
myAT.flush();
myAT.write(byteData, 0, byteData.length);
}
}
}
}

public int setLoopPoints (int startInFrames, int endInFrames, int loopCount)
Sets the loop points and the loop count. The loop can be infinite. Similarly to setPlaybackHeadPosition, the track must be stopped or paused for the position to be changed, and *must use the MODE_STATIC mode*.

The tick is probably the wav file header. Try offsetting the playback by 44 bytes.