rlm@3: package com.aurellem.capture;
rlm@3: 
rlm@3: 
rlm@3: /*************************************************************************
rlm@3:  *  Compilation:  javac StdAudio.java
rlm@3:  *  Execution:    java StdAudio
rlm@3:  *  
rlm@3:  *  Simple library for reading, writing, and manipulating .wav files.
rlm@3: 
rlm@3:  *
rlm@3:  *  Limitations
rlm@3:  *  -----------
rlm@3:  *    - Does not seem to work properly when reading .wav files from a .jar file.
rlm@3:  *    - Assumes the audio is monaural, with sampling rate of 44,100.
rlm@3:  *
rlm@3:  *************************************************************************/
rlm@3: 
rlm@3: import java.applet.Applet;
rlm@3: import java.applet.AudioClip;
rlm@3: import java.io.ByteArrayInputStream;
rlm@3: import java.io.File;
rlm@3: import java.net.MalformedURLException;
rlm@3: import java.net.URL;
rlm@3: 
rlm@3: import javax.sound.sampled.AudioFileFormat;
rlm@3: import javax.sound.sampled.AudioFormat;
rlm@3: import javax.sound.sampled.AudioInputStream;
rlm@3: import javax.sound.sampled.AudioSystem;
rlm@3: import javax.sound.sampled.SourceDataLine;
rlm@3: 
rlm@3: /**
rlm@3:  *  <i>Standard audio</i>. This class provides a basic capability for
rlm@3:  *  creating, reading, and saving audio. 
rlm@3:  *  <p>
rlm@3:  *  The audio format uses a sampling rate of 44,100 (CD quality audio), 16-bit, monaural.
rlm@3:  *
rlm@3:  *  <p>
rlm@3:  *  For additional documentation, see <a href="http://introcs.cs.princeton.edu/15inout">Section 1.5</a> of
rlm@3:  *  <i>Introduction to Programming in Java: An Interdisciplinary Approach</i> by Robert Sedgewick and Kevin Wayne.
rlm@3:  */
rlm@3: public final class StdAudio {
rlm@3: 
rlm@3:     /**
rlm@3:      *  The sample rate - 44,100 Hz for CD quality audio.
rlm@3:      */
rlm@3:     public static final int SAMPLE_RATE = 44100;
rlm@3: 
rlm@3:     //private static final int BYTES_PER_SAMPLE = 2;                // 16-bit audio
rlm@3:     //private static final int BITS_PER_SAMPLE = 16;                // 16-bit audio
rlm@3:     private static final double MAX_16_BIT = Short.MAX_VALUE;     // 32,767
rlm@3:     //private static final int SAMPLE_BUFFER_SIZE = 4096;
rlm@3: 
rlm@3: 
rlm@3:     private static SourceDataLine line;   // to play the sound
rlm@3:     private static byte[] buffer;         // our internal buffer
rlm@3:     private static int bufferSize = 0;    // number of samples currently in internal buffer
rlm@3: 
rlm@3:     // not-instantiable
rlm@3:     private StdAudio() { }
rlm@3: 
rlm@3:    
rlm@3:     // static initializer
rlm@3:     //static { init(); }
rlm@3: 
rlm@3:     // open up an audio stream
rlm@3:     
rlm@3:     /*
rlm@3:     private static void init() {
rlm@3:         try {
rlm@3:             // 44,100 samples per second, 16-bit audio, mono, signed PCM, little Endian
rlm@3:             AudioFormat format = new AudioFormat((float) SAMPLE_RATE, BITS_PER_SAMPLE, 1, true, false);
rlm@3:             DataLine.Info info = new DataLine.Info(SourceDataLine.class, format);
rlm@3: 
rlm@3:             line = (SourceDataLine) AudioSystem.getLine(info);
rlm@3:             
rlm@3:             // RLM: set to 1 and see what happens!
rlm@3:             line.open(format, SAMPLE_BUFFER_SIZE);
rlm@3:             //line.open(format, SAMPLE_BUFFER_SIZE * BYTES_PER_SAMPLE);
rlm@3:             
rlm@3:             // the internal buffer is a fraction of the actual buffer size, this choice is arbitrary
rlm@3:             // it gets divided because we can't expect the buffered data to line up exactly with when
rlm@3:             // the sound card decides to push out its samples.
rlm@3:             buffer = new byte[SAMPLE_BUFFER_SIZE * BYTES_PER_SAMPLE/3];
rlm@3:         } catch (Exception e) {
rlm@3:             System.out.println(e.getMessage());
rlm@3:             System.exit(1);
rlm@3:         }
rlm@3: 
rlm@3:         // no sound gets made before this call
rlm@3:         line.start();
rlm@3:     }
rlm@3:     */
rlm@3: 
rlm@3: 
rlm@3:     /**
rlm@3:      * Close standard audio.
rlm@3:      */
rlm@3:     public static void close() {
rlm@3:         line.drain();
rlm@3:         line.stop();
rlm@3:     }
rlm@3:     
rlm@3:     /**
rlm@3:      * Write one sample (between -1.0 and +1.0) to standard audio. If the sample
rlm@3:      * is outside the range, it will be clipped.
rlm@3:      */
rlm@3:     public static void play(double in) {
rlm@3: 
rlm@3:         // clip if outside [-1, +1]
rlm@3:         if (in < -1.0) in = -1.0;
rlm@3:         if (in > +1.0) in = +1.0;
rlm@3: 
rlm@3:         // convert to bytes
rlm@3:         short s = (short) (MAX_16_BIT * in);
rlm@3:         buffer[bufferSize++] = (byte) s;
rlm@3:         buffer[bufferSize++] = (byte) (s >> 8);   // little Endian
rlm@3: 
rlm@3:         // send to sound card if buffer is full        
rlm@3:         if (bufferSize >= buffer.length) {
rlm@3:             line.write(buffer, 0, buffer.length);
rlm@3:             bufferSize = 0;
rlm@3:         }
rlm@3:     }
rlm@3: 
rlm@3:     /**
rlm@3:      * Write an array of samples (between -1.0 and +1.0) to standard audio. If a sample
rlm@3:      * is outside the range, it will be clipped.
rlm@3:      */
rlm@3:     public static void play(double[] input) {
rlm@3:         for (int i = 0; i < input.length; i++) {
rlm@3:             play(input[i]);
rlm@3:         }
rlm@3:     }
rlm@3: 
rlm@3:     /**
rlm@3:      * Read audio samples from a file (in .wav or .au format) and return them as a double array
rlm@3:      * with values between -1.0 and +1.0.
rlm@3:      */
rlm@3:     public static double[] read(String filename) {
rlm@3:         byte[] data = readByte(filename);
rlm@3:         int N = data.length;
rlm@3:         double[] d = new double[N/2];
rlm@3:         for (int i = 0; i < N/2; i++) {
rlm@3:             d[i] = ((short) (((data[2*i+1] & 0xFF) << 8) + (data[2*i] & 0xFF))) / ((double) MAX_16_BIT);
rlm@3:         }
rlm@3:         return d;
rlm@3:     }
rlm@3: 
rlm@3: 
rlm@3: 
rlm@3: 
rlm@3:     /**
rlm@3:      * Play a sound file (in .wav or .au format) in a background thread.
rlm@3:      */
rlm@3:     public static void play(String filename) {
rlm@3:         URL url = null;
rlm@3:         try {
rlm@3:             File file = new File(filename);
rlm@3:             if (file.canRead()) url = file.toURI().toURL();
rlm@3:         }
rlm@3:         catch (MalformedURLException e) { e.printStackTrace(); }
rlm@3:         // URL url = StdAudio.class.getResource(filename);
rlm@3:         if (url == null) throw new RuntimeException("audio " + filename + " not found");
rlm@3:         AudioClip clip = Applet.newAudioClip(url);
rlm@3:         clip.play();
rlm@3:     }
rlm@3: 
rlm@3:     /**
rlm@3:      * Loop a sound file (in .wav or .au format) in a background thread.
rlm@3:      */
rlm@3:     public static void loop(String filename) {
rlm@3:         URL url = null;
rlm@3:         try {
rlm@3:             File file = new File(filename);
rlm@3:             if (file.canRead()) url = file.toURI().toURL();
rlm@3:         }
rlm@3:         catch (MalformedURLException e) { e.printStackTrace(); }
rlm@3:         // URL url = StdAudio.class.getResource(filename);
rlm@3:         if (url == null) throw new RuntimeException("audio " + filename + " not found");
rlm@3:         AudioClip clip = Applet.newAudioClip(url);
rlm@3:         clip.loop();
rlm@3:     }
rlm@3: 
rlm@3: 
rlm@3:     // return data as a byte array
rlm@3:     private static byte[] readByte(String filename) {
rlm@3:         byte[] data = null;
rlm@3:         AudioInputStream ais = null;
rlm@3:         try {
rlm@3:             URL url = StdAudio.class.getResource(filename);
rlm@3:             ais = AudioSystem.getAudioInputStream(url);
rlm@3:             data = new byte[ais.available()];
rlm@3:             ais.read(data);
rlm@3:         }
rlm@3:         catch (Exception e) {
rlm@3:             System.out.println(e.getMessage());
rlm@3:             throw new RuntimeException("Could not read " + filename);
rlm@3:         }
rlm@3: 
rlm@3:         return data;
rlm@3:     }
rlm@3: 
rlm@3: 
rlm@3: 
rlm@3:     /**
rlm@3:      * Save the double array as a sound file (using .wav or .au format).
rlm@3:      */
rlm@3:     public static void save(String filename, double[] input) {
rlm@3: 
rlm@3:         // assumes 44,100 samples per second
rlm@3:         // use 16-bit audio, mono, signed PCM, little Endian
rlm@3:         AudioFormat format = new AudioFormat(SAMPLE_RATE, 16, 1, true, false);
rlm@3:         byte[] data = new byte[2 * input.length];
rlm@3:         for (int i = 0; i < input.length; i++) {
rlm@3:             int temp = (short) (input[i] * MAX_16_BIT);
rlm@3:             data[2*i + 0] = (byte) temp;
rlm@3:             data[2*i + 1] = (byte) (temp >> 8);
rlm@3:         }
rlm@3: 
rlm@3:         // now save the file
rlm@3:         try {
rlm@3:             ByteArrayInputStream bais = new ByteArrayInputStream(data);
rlm@3:             AudioInputStream ais = new AudioInputStream(bais, format, input.length);
rlm@3:             if (filename.endsWith(".wav") || filename.endsWith(".WAV")) {
rlm@3:                 AudioSystem.write(ais, AudioFileFormat.Type.WAVE, new File(filename));
rlm@3:             }
rlm@3:             else if (filename.endsWith(".au") || filename.endsWith(".AU")) {
rlm@3:                 AudioSystem.write(ais, AudioFileFormat.Type.AU, new File(filename));
rlm@3:             }
rlm@3:             else {
rlm@3:                 throw new RuntimeException("File format not supported: " + filename);
rlm@3:             }
rlm@3:         }
rlm@3:         catch (Exception e) {
rlm@3:             System.out.println(e);
rlm@3:             System.exit(1);
rlm@3:         }
rlm@3:     }
rlm@3:     
rlm@3:     public static void save(String filename, byte[] data){
rlm@3:     	 // now save the file
rlm@3:         AudioFormat format = new AudioFormat(SAMPLE_RATE, 32, 1, true, false);
rlm@3: 
rlm@3:         try {
rlm@3:             ByteArrayInputStream bais = new ByteArrayInputStream(data);
rlm@3:             AudioInputStream ais = new AudioInputStream(bais, format, data.length/2);
rlm@3:             if (filename.endsWith(".wav") || filename.endsWith(".WAV")) {
rlm@3:                 AudioSystem.write(ais, AudioFileFormat.Type.WAVE, new File(filename));
rlm@3:             }
rlm@3:             else if (filename.endsWith(".au") || filename.endsWith(".AU")) {
rlm@3:                 AudioSystem.write(ais, AudioFileFormat.Type.AU, new File(filename));
rlm@3:             }
rlm@3:             else {
rlm@3:                 throw new RuntimeException("File format not supported: " + filename);
rlm@3:             }
rlm@3:         }
rlm@3:         catch (Exception e) {
rlm@3:             System.out.println(e);
rlm@3:             System.exit(1);
rlm@3:         }
rlm@3:     }
rlm@3: 
rlm@3:     /*
rlm@3:     public static void save(String filename, Byte[] data){
rlm@3:    	 // now save the file
rlm@3:       save(filename, ArrayUtils.toPrimitive(data));
rlm@3:        
rlm@3:    }
rlm@3:    */
rlm@3: 
rlm@3:    /***********************************************************************
rlm@3:     * sample test client
rlm@3:     ***********************************************************************/
rlm@3: 
rlm@3:     // create a note (sine wave) of the given frequency (Hz), for the given
rlm@3:     // duration (seconds) scaled to the given volume (amplitude)
rlm@3:     private static double[] note(double hz, double duration, double amplitude) {
rlm@3:         int N = (int) (StdAudio.SAMPLE_RATE * duration);
rlm@3:         double[] a = new double[N+1];
rlm@3:         for (int i = 0; i <= N; i++)
rlm@3:             a[i] = amplitude * Math.sin(2 * Math.PI * i * hz / StdAudio.SAMPLE_RATE);
rlm@3:         return a;
rlm@3:     }
rlm@3: 
rlm@3:     /**
rlm@3:      * Test client - play an A major scale to standard audio.
rlm@3:      */
rlm@3:     public static void main(String[] args) {
rlm@3:         
rlm@3:         // 440 Hz for 1 sec
rlm@3:         double freq = 440.0;
rlm@3:         for (int i = 0; i <= StdAudio.SAMPLE_RATE; i++) {
rlm@3:             StdAudio.play(0.5 * Math.sin(2*Math.PI * freq * i / StdAudio.SAMPLE_RATE));
rlm@3:         }
rlm@3:         
rlm@3:         // scale increments
rlm@3:         int[] steps = { 0, 2, 4, 5, 7, 9, 11, 12 };
rlm@3:         for (int i = 0; i < steps.length; i++) {
rlm@3:             double hz = 440.0 * Math.pow(2, steps[i] / 12.0);
rlm@3:             StdAudio.play(note(hz, 1.0, 0.5));
rlm@3:         }
rlm@3: 
rlm@3: 
rlm@3:         // need to call this in non-interactive stuff so the program doesn't terminate
rlm@3:         // until all the sound leaves the speaker.
rlm@3:         StdAudio.close(); 
rlm@3: 
rlm@3:         // need to terminate a Java program with sound
rlm@3:         System.exit(0);
rlm@3:     }
rlm@3: }
rlm@3: