StreamingAudioFileBuffer.java

package jass.generators;
import jass.engine.*;
import jass.render.*;
import javax.sound.sampled.*;
import java.io.*;
import java.net.*;

/**
   A buffer from an audio file or URL, streamed off the source.
   Assumes 16 bit audio format.
   @author Kees van den Doel (kvdoel@cs.ubc.ca)
*/
public class StreamingAudioFileBuffer { 
    /** Sampling rate  in Hertz. */
    public float srate;

    /** Bytes per frame (2 for mono, 4 stereo, etc.) */
    public int bytesPerFrame;

    /** # frames */
    public long nFrames;

    /** bytes */
    public int numBytes;
        
    /** Bits per sample */
    public int bitsPerSample;

    /** Number of channels */
    public int nChannels;
    
    /** Length of buffer as floats, should be numBytes/2. */
    public int bufsz;

    // to get audio data
    public AudioInputStream audioInputStream = null;

    // temp buffer
    private byte[] audioBytes = null;

    /** Construct buffer from named file.
        @param fn Audio file name.
    */
    public StreamingAudioFileBuffer(String fn) throws UnsupportedAudioFileFormatException {
        loadAudio(fn);
    }

    /** Construct buffer from  url.
        @param url Audiofile url.
    */
    public StreamingAudioFileBuffer(URL url) throws UnsupportedAudioFileFormatException {
        loadAudio(url);
    }
    /** Close stream */
    public void close() {
        try {
            audioInputStream.close();
        } catch(Exception e) {
            System.out.println(e);
        }
        audioInputStream = null;
    }

    /** Open and read audio file properties and prepare for streaming
        @param fn Audio file name.
    */
    protected void loadAudio(String fn) throws UnsupportedAudioFileFormatException {
        File fileIn = new File(fn);
        try {
            audioInputStream = AudioSystem.getAudioInputStream(fileIn);
        } catch (Exception e) {
            System.out.println("Error reading audio file " + fn);
        }
        doRestOfLoad();
    }
    
    /** Open and read audio URL properties and prepare for streaming
        @param url Audiofile url.
    */
    protected void loadAudio(URL url) throws UnsupportedAudioFileFormatException {
        try {
            audioInputStream = AudioSystem.getAudioInputStream(url);
        } catch (Exception e) {
            System.out.println(e+" Error reading audio url " + url);
        }
        doRestOfLoad();
    }

    private void doRestOfLoad() throws UnsupportedAudioFileFormatException {
        bytesPerFrame = audioInputStream.getFormat().getFrameSize();
        System.out.println("marksupported="+audioInputStream.markSupported());
        bitsPerSample = audioInputStream.getFormat().getSampleSizeInBits();
        if(bitsPerSample != 16) {
            throw new UnsupportedAudioFileFormatException("not 16 bits audio");
        }
        nChannels = audioInputStream.getFormat().getChannels();
        if(nChannels != 1) {
            throw new UnsupportedAudioFileFormatException("not 1 channel audio");
        }
        srate = (float)audioInputStream.getFormat().getSampleRate();
        nFrames = audioInputStream.getFrameLength();
        numBytes = (int)nFrames * bytesPerFrame; 
        bufsz = numBytes/2;
        int readLimit = numBytes;
        audioInputStream.mark(readLimit);
    }

}