Java convert uLaw encoded audio file to PCM ecoded

[Moonis Ahmed]

Hi, I want to convert a ULAW encoded .wav file into a PCM encoded one. The ULAW encoded .wav file is of 8 bit, mono with 8Khz sample rate. How can I achieve this. I have written a code below but it gives error that the conversion is not supported. I am using javax.sound.sampled class. below is the code.

try{

File temp = new File("C:/temp.wav");
File fileout = new File("C:/1java.wav");
AudioInputStream sourceaudio = AudioSystem.getAudioInputStream(temp);
AudioFormat targetformat = new AudioFormat(new AudioFormat.Encoding("PCM\_UNSIGNED"),8000,16,0,8,8000,true);
AudioFileFormat.Type targettype = AudioFileFormat.Type.WAVE;
AudioInputStream targetaudiostream = AudioSystem.getAudioInputStream(targetformat,sourceaudio);
AudioSystem.write(targetaudiostream, targettype, fileout);
}
catch(Exception e){
    out.println("Error in audio format conversion");
    e.printStackTrace();
    }

[4277480]

I personally did not try this but I found this link that will solve your problem http://www.mms-computing.co.uk/uk/co/mmscomputing/sound/ Do tell if you figure it out

[Moonis Ahmed]

Hi, I was able to solve it using the inherent java audio class javax.sound.sampled. I convert an input audio file encoded in uLaw to PCM and then write the PCM file into an Audiostream. Code is given below.

try{
File filein = new File("C:/sourcefile.wav");
File fileout = new File("C:/PCMfile.wav");
AudioInputStream sourceaudio = AudioSystem.getAudioInputStream(filein);
AudioFormat format = sourceaudio.getFormat();
if (format.getEncoding() != AudioFormat.Encoding.PCM_SIGNED) {
format = new AudioFormat(
AudioFormat.Encoding.PCM_SIGNED,
format.getSampleRate(),
format.getSampleSizeInBits() * 2,
format.getChannels(),
format.getFrameSize() * 2,
format.getFrameRate(),
true);
}
AudioFileFormat.Type targettype = AudioFileFormat.Type.WAVE;
AudioInputStream targetaudiostream = AudioSystem.getAudioInputStream(format, sourceaudio);
AudioSystem.write(targetaudiostream, targettype, fileout);
System.out.println("PCM encoded file generated successfully.");
sourceaudio.close();
targetaudiostream.close();
} catch (Exception e) {
out.println("Error in audio format conversion");
e.printStackTrace();
}