annotate audio/java/AudioSink.java @ 61:eff6bddf82e3 tip

Finally implemented perceptual brightness thing.

/*
 *	AudioSink.java
 *
 *	Copyright (c) 2000, Samer Abdallah, King's College London.
 *	All rights reserved.
 *
 *	This software is provided AS iS and WITHOUT ANY WARRANTY;
 *	without even the implied warranty of MERCHANTABILITY or
 *	FITNESS FOR A PARTICULAR PURPOSE.
 */

package ishara.audio;
import  javax.sound.sampled.AudioFormat;

/**
	General interface for objects that accept a stream of
	samples.
*/

public abstract class AudioSink
{
	AudioFormat format;
	double		scale;

	public AudioSink(AudioFormat f) { format=f; }
	public AudioFormat getFormat() { return format; }

	public double getScale() { return scale; }
	public void   setScale(double s) { scale=s; }

	public abstract void dispose();
	public abstract void start();
	public abstract void stop();
	public abstract int  bwrite(byte [] bbuf, int offs, int len) throws Exception;

	/** Return a task which takes samples from the given buffer
	 *  The idea is that the audio sink can choose the right
	 *  kind of writer depending on the format of the audio stream,
	 *  and then handle any conversions automatically.
	 *  Should return the number of samples NOT written.
	 */

	public Writer writer(int len) { 
		return new Writer(len,format.getSampleSizeInBits()/8); 
	}

	public class Writer {
		byte[]  	bbuf;
		int		bps;
		Converter conv;

		public Writer(int len, int bps) {
			this.bps=bps;
			bbuf=new byte[len*bps];
			conv=getConverter(bbuf,bps);
		}

		public int write(double dbuf[]) throws Exception { return write(dbuf,0,dbuf.length); }
		public int write(double dbuf[], int off, int len) throws Exception {
			conv.convert(dbuf,off,len);
			int rem=len*bps, pos=0;
			while (rem>0) {
				int count = bwrite(bbuf, pos, rem);
				if (count<=0) { return rem; }
				rem -= count; pos += count;
			}
			return 0;
		}
	}

	private interface Converter { public void convert(double [] dbuf, int offset, int count); }
	private Converter getConverter(final byte [] b,final int bps) {
		switch (bps) {
			case 1: return new Converter() { public void convert(double[] d,int i, int n) { Util.doubleToByte(d,b,i,n,scale); } };
			case 2: return new Converter() { public void convert(double[] d,int i, int n) { Util.doubleToShort(d,b,i,n,scale); } };
			case 3: return new Converter() { public void convert(double[] d,int i, int n) { Util.doubleToMedium(d,b,i,n,scale); } };
			case 4: return new Converter() { public void convert(double[] d,int i, int n) { Util.doubleToInt(d,b,i,n,scale); } };
		}
		throw new Error("Unrecognised sample format");
	}

	protected static void print(String msg) { System.out.println(msg); }
}