AudioReader.java

package com.nicolamontecchio.chroma;

import java.io.*;
import javax.sound.sampled.*;

/**
 * Read an audio file. Provided that the appropriate packages are in the classpath, mp3 and ogg should be readable too. The safest route is to read from a MONO, WAV file.
 */
public class AudioReader {

	private AudioInputStream signedBigEndianInputStream = null;
	private AudioInputStream originalAudioInputStream = null;

	public AudioReader(File inputfile) throws UnsupportedAudioFileException, IOException {
		originalAudioInputStream = AudioSystem.getAudioInputStream(inputfile);
		AudioFormat destaf = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
						originalAudioInputStream.getFormat().getSampleRate(),
						16, originalAudioInputStream.getFormat().getChannels(),
						16 / 8 * originalAudioInputStream.getFormat().getChannels(),
						originalAudioInputStream.getFormat().getSampleRate(), true);
		signedBigEndianInputStream = AudioSystem.getAudioInputStream(destaf, originalAudioInputStream);
	}

	/**
	 * Read next n samples (at most) from file (convert automatically to MONO). Return as double[].
	 */
	public double[] readDoubleSamples(int n) throws IOException {
		int channels = signedBigEndianInputStream.getFormat().getChannels();
		int ss = signedBigEndianInputStream.getFormat().getSampleSizeInBits();
		int ssB = ss / 8; // in bytes
		//		System.out.println(String.format("fl: %d, ss: %d, ssB: %d, samplerate: %f",
		//						fl, ss, ssB, signedBigEndianInputStream.getFormat().getSampleRate()));
		byte[] b = new byte[n * channels * ssB];
		int read = signedBigEndianInputStream.read(b);
		double[] res = new double[read / ssB / channels];
		for (int i = 0; i < res.length; i++) 
			res[i] = 0;
		
		for (int i = 0; i < res.length * channels; i++) {
			double val = 0;
			switch (ss) {
				case 8:
					val = ((b[i * ssB] & 0xFF) - 128) / 128.0;
					break;
				case 16:
					val = ((b[i * ssB + 0] << 8) | (b[i * ssB + 1] & 0xFF)) / 32768.0;
					break;
				case 24:
					val = ((b[i * ssB + 0] << 16) | ((b[i * ssB + 1] & 0xFF) << 8)
									| (b[i * ssB + 2] & 0xFF)) / 8388606.0;
					break;
				case 32:
					val = ((b[i * ssB + 0] << 24) | ((b[i * ssB + 1] & 0xFF) << 16)
									| ((b[i * ssB + 2] & 0xFF) << 8) | (b[i * ssB + 3] & 0xFF)) / 2147483648.0;
					break;
			}
			res[i/channels] += val / channels;
		}
		return res;
	}

	public float getSampleRate() {
		return signedBigEndianInputStream.getFormat().getSampleRate();

	}

	public void close() throws IOException {
		signedBigEndianInputStream.close();
		originalAudioInputStream.close();
	}
}

Hello,
if its not too much too ask, can u please give a working demo(through driver class)?
Like i am confused what to pass (samples per second or total samples in whole audio) as 'n' in readDoubleSamples.
PS. I am a noob.