In my app i have created an audio player (only WAV files) using
MediaPlayer<http://developer.android.com/reference/android/media/MediaPlayer.html>API.
But the player doesn't give callback to onCompletion Listener
everytime. Sometimes it gives callback but not everytime. I am doing some
audio processing on wav file , like insertion and overwriting.
Is it because any missing in audio header? Why it doesn't give callback
when the playback is completed?
here is the code:
mMediaPlayer.setOnCompletionListener(new OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
// realease media player
// update player ui
}
});
<http://stackoverflow.com/questions/tagged/android>
Here is the code how i create and update wav header:
public void createWAVHeader(int sRate,int byteRate,int nChannels,int
BitsPerSample,long length){
byte[] header = new byte[44];
header[0] = 'R'; // RIFF/WAVE header
header[1] = 'I';
header[2] = 'F';
header[3] = 'F';
header[4] = (byte) ((length+36) & 0xff);
header[5] = (byte) (((length+36) >> 8) & 0xff);
header[6] = (byte) (((length+36) >> 16) & 0xff);
header[7] = (byte) (((length+36) >> 24) & 0xff);
header[8] = 'W';
header[9] = 'A';
header[10] = 'V';
header[11] = 'E';
header[12] = 'f'; // 'fmt ' chunk
header[13] = 'm';
header[14] = 't';
header[15] = ' ';
header[16] = 16; // 4 bytes: size of 'fmt ' chunk
header[17] = 0;
header[18] = 0;
header[19] = 0;
header[20] = 1; // format = 1
header[21] = 0;
header[22] = (byte) nChannels;
header[23] = 0;
header[24] = (byte) (sRate & 0xff);
header[25] = (byte) ((sRate >> 8) & 0xff);
header[26] = (byte) ((sRate >> 16) & 0xff);
header[27] = (byte) ((sRate >> 24) & 0xff);
header[28] = (byte) (byteRate & 0xff);
header[29] = (byte) ((byteRate >> 8) & 0xff);
header[30] = (byte) ((byteRate >> 16) & 0xff);
header[31] = (byte) ((byteRate >> 24) & 0xff);
header[32] = (byte) (2 * 16 / 8); // block align
header[33] = 0;
header[34] = (byte) BitsPerSample; // bits per sample
header[35] = 0;
header[36] = 'd';
header[37] = 'a';
header[38] = 't';
header[39] = 'a';
header[40] = (byte) (length & 0xff);
header[41] = (byte) ((length >> 8) & 0xff);
header[42] = (byte) ((length >> 16) & 0xff);
header[43] = (byte) ((length >> 24) & 0xff);
try {
rafOut.write(header, 0, 44);
} catch (IOException e) {
e.printStackTrace();
}}
Here is the code for updating the header when new audio data is been
recorded
public void updateHeader(String inFile){
long totalAudioLen = 0;
long totalDataLen =0; // totalAudioLen + 36
FileInputStream in = null;
try
{
in = new FileInputStream(inFile);
totalAudioLen = (in.getChannel().size()-44);
totalDataLen = (totalAudioLen) + 36;
RandomAccessFile invFile = new RandomAccessFile(inFile, "rw");
invFile.seek(4);
invFile.write((byte) (totalDataLen & 0xff));
invFile.write((byte) ((totalDataLen >> 8) & 0xff));
invFile.write((byte) ((totalDataLen >> 16) & 0xff));
invFile.write((byte) ((totalDataLen >> 24) & 0xff));
invFile.seek(40);
invFile.write((byte) (totalAudioLen & 0xff));
invFile.write((byte) ((totalAudioLen >> 8) & 0xff));
invFile.write((byte) ((totalAudioLen >> 16) & 0xff));
invFile.write((byte) ((totalAudioLen >> 24) & 0xff));
invFile.close();
}catch (Exception e) {
// TODO: handle exception
}
}
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