Convert PCM encoded wav file to amr file using AmrInputStream, but not able to play it using MediaPlayer

Question

I am converting a PCM encoded wav file to amr file in Android using AmrInputStream. I used the code from below post:

converting PCM-16 to AMR using AmrInputStream

Everything works fine, and the amr file is also generated. However, when I tried to play it with MeidaPlayer, it thrown following exception:

   java.io.IOException: Prepare failed.: status=0xFFFFFFFC  
      at android.media.MediaPlayer.prepare(Native Method)

I noticed that in the above post, it mentioned: "requiring adding the #AMR!\n tag to the output file for playing.". but I don't know how to do it exactly. Please help!

Answer 1

Ok, I made it working. need to add the tag in the first 6 bytes of the output file:

    InputStream inStream;
    inStream = new FileInputStream(wavFilename);
    AmrInputStream aStream = new AmrInputStream(inStream);

    File file = new File(amrFilename);        
    file.createNewFile();
    OutputStream out = new FileOutputStream(file); 

    out.write(0x23);
    out.write(0x21);
    out.write(0x41);
    out.write(0x4D);
    out.write(0x52);
    out.write(0x0A);    

    byte[] x = new byte[1024];
    int len;
    while ((len=aStream.read(x)) > 0) {
        out.write(x,0,len);
    }

    out.close();