Server-side AAC audio with Android

Question

As I understand it, Android will only play AAC format audio if it's encoded as MPEG-4 or 3GPP.

I'm able to play AAC audio encoded as M4A when it's local to the app, but it fails when obtaining it from a server.

The following works, as the m4a file is held locally in the res/raw directory.

MediaPlayer mp = MediaPlayer.create(this, R.raw.*file*);
mp.start();

The following doesn't work. (But does with MP3's).

Uri uri = Uri.parse("http://*example.com*/blah.m4a");
MediaPlayer mp = MediaPlayer.create(this, uri);
mp.start();

Can anyone shed any light on why it fails when the m4a audio file is not local?

Here's (some of) the error...

ERROR/PlayerDriver(542): Command PLAYER_INIT completed with an error or info UNKNOWN PVMFStatus
ERROR/MediaPlayer(769): error (200, -32)  
WARN/PlayerDriver(542): PVMFInfoErrorHandlingComplete  
DEBUG/MediaPlayer(769): create failed:  
DEBUG/MediaPlayer(769): java.io.IOException: Prepare failed.: status=0xC8  
DEBUG/MediaPlayer(769):     at android.media.MediaPlayer.prepare(Native Method)  
DEBUG/MediaPlayer(769):     at android.media.MediaPlayer.create(MediaPlayer.java:530)  
DEBUG/MediaPlayer(769):     at android.media.MediaPlayer.create(MediaPlayer.java:507)   
...

I'm targeting SDK 1.6.

Answer 1

This is a wild shot in the dark, but I have seen similar behavior with the flash player where it actually ignores the file name and only relies on the MIME type sent by the server. Any idea what headers are being sent down from example.com? You might want to try wrapping your blah.m4a in a page that can set the headers and then stream the binary data. Give these types a shot and the community would appreciate a confirmation of what works:

audio/mpeg audio/mp4a audio/mp4a-latm audio/aac audio/x-aac

Answer 2

This work-around allows you to play M4A files from the net (and AAC files in other containers such as MP4 & 3GP). It simply downloads the file and plays from the cache.

private File mediaFile;

private void playAudio(String mediaUrl) {
    try {
     URLConnection cn = new URL(mediaUrl).openConnection();
        InputStream is = cn.getInputStream();

        // create file to store audio
        mediaFile = new File(this.getCacheDir(),"mediafile");
        FileOutputStream fos = new FileOutputStream(mediaFile);   
        byte buf[] = new byte[16 * 1024];
        Log.i("FileOutputStream", "Download");

        // write to file until complete
        do {
         int numread = is.read(buf);   
            if (numread <= 0)  
                break;
            fos.write(buf, 0, numread);
        } while (true);
        fos.flush();
        fos.close();
        Log.i("FileOutputStream", "Saved");
        MediaPlayer mp = new MediaPlayer();

        // create listener to tidy up after playback complete
     MediaPlayer.OnCompletionListener listener = new MediaPlayer.OnCompletionListener() {
      public void onCompletion(MediaPlayer mp) {
       // free up media player
       mp.release();
       Log.i("MediaPlayer.OnCompletionListener", "MediaPlayer Released");
      }
     };
        mp.setOnCompletionListener(listener);

        FileInputStream fis = new FileInputStream(mediaFile);
        // set mediaplayer data source to file descriptor of input stream
        mp.setDataSource(fis.getFD());
        mp.prepare();
        Log.i("MediaPlayer", "Start Player");
        mp.start();
    } catch (Exception e) {
     e.printStackTrace();
    }
}

Answer 3

try --

1) MP.prepareAsync

2) onPrepared() { mp.start() }

Answer 4

I wrote a smal blog on a cloud-based solution I use for a music player I'm developing. It's based on the young Android Cloud Services (ACS) project, which isn't available yet, but still, it shows a potential solution using cloud-based transcoding to stream any media files. Have a look : http://positivelydisruptive.blogspot.com/2010/08/streaming-m4a-files-using-android-cloud.html

Joel