Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>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.</p> <p>I recently had to solve a similar problem with video playback. Thanks to <code>MediaPlayer</code> being unable to play an arbitrary <code>InputStream</code> (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. <code>MediaPlayer</code> then loads it via a URI of the form <a href="http://127.0.0.1:8888/videofilename">http://127.0.0.1:8888/videofilename</a>.</p> <p><strong>EDIT:</strong></p> <p>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 <code>MediaPlayer.setDataSource("http://127.0.0.1:8888/localfilepath");</code></p> <p>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).</p> <pre><code>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&lt;String, Void, Integer&gt; { 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&lt;headerLines.length ; i++) { String headerLine = headerLines[i]; if (headerLine.startsWith("Range: bytes=")) { headerLine = headerLine.substring(13); charPos = headerLine.indexOf('-'); if (charPos&gt;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 &amp;&amp; cbToSend&gt;0 &amp;&amp; !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 &gt; 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; } } } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POMediaPlayer stutters at start of mp3 playback
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USReuben Scratton
    1. USReuben Scratton
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POMediaPlayer stutters at start of mp3 playback
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTBountyClose
    1. COInteresting. Are you suggesting that I decode the mp3 files into something uncompressed (like PCM/WAVE) and feed that to MediaPlayer?
      singulars
      1. PO
      1. USTed Hopp
    2. CONot at all, I'm suggesting that you preload some or all of the compressed data into memory. I think your problem is that when you simply give MediaPlayer a FileDescriptor, it doesn't buffer up enough data to feed into the MP3 decompressor... you suffer a buffer underrun, hence the stuttering.
      singulars
      1. PO
      1. USReuben Scratton
    3. COAh. That would explain why the trick of calling start() and then pause() right at the beginning would have an effect. I'm theorizing that it wasn't fully effective because the call to pause() came too soon, so the buffer didn't have a chance to fill up. I replaced the start/pause sequence with a call to seekTo(500) (and fiddled a bit with onSeekComplete) and the stutter now seems to have gone away!
      singulars
      1. PO
      1. USTed Hopp
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload