MediaPlayer stutters at start of mp3 playback
AFAIK the buffers that MediaPlayer creates internally are for storing decompressed samples, not for storing prefetched compressed data. I suspect your stuttering comes from I/O slowness as it loads more MP3 data for decompression.
I recently had to solve a similar problem with video playback. Thanks to MediaPlayer being unable to play an arbitrary InputStream (the API is strangely lame) the solution I came up with was to write a small in-process webserver for serving up local files (on the SD card) over HTTP. MediaPlayer then loads it via a URI of the form http://127.0.0.1:8888/videofilename.
EDIT:
Below is the StreamProxy class I use to feed content into a MediaPlayer instance. The basic use is that you instantiate it, start() it, and set your media player going with something like MediaPlayer.setDataSource("http://127.0.0.1:8888/localfilepath");
I should note that it is rather experimental and probably not entirely bug-free. It was written to solve a similar problem to yours, namely that MediaPlayer cannot play a file that is also being downloaded. Streaming a file locally in this way works around that restriction (i.e. I have a thread downloading the file while the StreamProxy feeds it into mediaplayer).
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.net.SocketTimeoutException;
import java.net.UnknownHostException;
import android.os.AsyncTask;
import android.os.Looper;
import android.util.Log;
public class StreamProxy implements Runnable {
private static final int SERVER_PORT=8888;
private Thread thread;
private boolean isRunning;
private ServerSocket socket;
private int port;
public StreamProxy() {
// Create listening socket
try {
socket = new ServerSocket(SERVER_PORT, 0, InetAddress.getByAddress(new byte[] {127,0,0,1}));
socket.setSoTimeout(5000);
port = socket.getLocalPort();
} catch (UnknownHostException e) { // impossible
} catch (IOException e) {
Log.e(TAG, "IOException initializing server", e);
}
}
public void start() {
thread = new Thread(this);
thread.start();
}
public void stop() {
isRunning = false;
thread.interrupt();
try {
thread.join(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
@Override
public void run() {
Looper.prepare();
isRunning = true;
while (isRunning) {
try {
Socket client = socket.accept();
if (client == null) {
continue;
}
Log.d(TAG, "client connected");
StreamToMediaPlayerTask task = new StreamToMediaPlayerTask(client);
if (task.processRequest()) {
task.execute();
}
} catch (SocketTimeoutException e) {
// Do nothing
} catch (IOException e) {
Log.e(TAG, "Error connecting to client", e);
}
}
Log.d(TAG, "Proxy interrupted. Shutting down.");
}
private class StreamToMediaPlayerTask extends AsyncTask<String, Void, Integer> {
String localPath;
Socket client;
int cbSkip;
public StreamToMediaPlayerTask(Socket client) {
this.client = client;
}
public boolean processRequest() {
// Read HTTP headers
String headers = "";
try {
headers = Utils.readTextStreamAvailable(client.getInputStream());
} catch (IOException e) {
Log.e(TAG, "Error reading HTTP request header from stream:", e);
return false;
}
// Get the important bits from the headers
String[] headerLines = headers.split("\n");
String urlLine = headerLines[0];
if (!urlLine.startsWith("GET ")) {
Log.e(TAG, "Only GET is supported");
return false;
}
urlLine = urlLine.substring(4);
int charPos = urlLine.indexOf(' ');
if (charPos != -1) {
urlLine = urlLine.substring(1, charPos);
}
localPath = urlLine;
// See if there's a "Range:" header
for (int i=0 ; i<headerLines.length ; i++) {
String headerLine = headerLines[i];
if (headerLine.startsWith("Range: bytes=")) {
headerLine = headerLine.substring(13);
charPos = headerLine.indexOf('-');
if (charPos>0) {
headerLine = headerLine.substring(0,charPos);
}
cbSkip = Integer.parseInt(headerLine);
}
}
return true;
}
@Override
protected Integer doInBackground(String... params) {
long fileSize = GET CONTENT LENGTH HERE;
// Create HTTP header
String headers = "HTTP/1.0 200 OK\r\n";
headers += "Content-Type: " + MIME TYPE HERE + "\r\n";
headers += "Content-Length: " + fileSize + "\r\n";
headers += "Connection: close\r\n";
headers += "\r\n";
// Begin with HTTP header
int fc = 0;
long cbToSend = fileSize - cbSkip;
OutputStream output = null;
byte[] buff = new byte[64 * 1024];
try {
output = new BufferedOutputStream(client.getOutputStream(), 32*1024);
output.write(headers.getBytes());
// Loop as long as there's stuff to send
while (isRunning && cbToSend>0 && !client.isClosed()) {
// See if there's more to send
File file = new File(localPath);
fc++;
int cbSentThisBatch = 0;
if (file.exists()) {
FileInputStream input = new FileInputStream(file);
input.skip(cbSkip);
int cbToSendThisBatch = input.available();
while (cbToSendThisBatch > 0) {
int cbToRead = Math.min(cbToSendThisBatch, buff.length);
int cbRead = input.read(buff, 0, cbToRead);
if (cbRead == -1) {
break;
}
cbToSendThisBatch -= cbRead;
cbToSend -= cbRead;
output.write(buff, 0, cbRead);
output.flush();
cbSkip += cbRead;
cbSentThisBatch += cbRead;
}
input.close();
}
// If we did nothing this batch, block for a second
if (cbSentThisBatch == 0) {
Log.d(TAG, "Blocking until more data appears");
Thread.sleep(1000);
}
}
}
catch (SocketException socketException) {
Log.e(TAG, "SocketException() thrown, proxy client has probably closed. This can exit harmlessly");
}
catch (Exception e) {
Log.e(TAG, "Exception thrown from streaming task:");
Log.e(TAG, e.getClass().getName() + " : " + e.getLocalizedMessage());
e.printStackTrace();
}
// Cleanup
try {
if (output != null) {
output.close();
}
client.close();
}
catch (IOException e) {
Log.e(TAG, "IOException while cleaning up streaming task:");
Log.e(TAG, e.getClass().getName() + " : " + e.getLocalizedMessage());
e.printStackTrace();
}
return 1;
}
}
}
Would using prepareAsync and responding to setOnPreparedListener suit you better? Depending on your activity workflow, when the MediaPlayer is first initialized you could set the preparation listener and then call mPlayer.prepareAsync() later once you're actually loading the resource, then start playback there. I use something similar, albeit for a network-based streaming resource:
MediaPlayer m_player;
private ProgressDialog m_progressDialog = null;
...
try {
if (m_player != null) {
m_player.reset();
} else {
m_player = new MediaPlayer();
}
m_progressDialog = ProgressDialog
.show(this,
getString(R.string.progress_dialog_please_wait),
getString(R.string.progress_dialog_buffering),
true);
m_player.setOnPreparedListener(this);
m_player.setAudioStreamType(AudioManager.STREAM_MUSIC);
m_player.setDataSource(someSource);
m_player.prepareAsync();
} catch (Exception ex) {
}
...
public void onPrepared(MediaPlayer mp) {
if (m_progressDialog != null && m_progressDialog.isShowing()) {
m_progressDialog.dismiss();
}
m_player.start();
}
There's obviously more to a complete solution (error-handling, etc.) but I think this should work as a good example to start from that you can pull the streaming out of.