AudioChunk.java

/*
  AudioChunk.java

  (c) 2010-2016 Edward Swartz

  All rights reserved. This program and the accompanying materials
  are made available under the terms of the Eclipse Public License v1.0
  which accompanies this distribution, and is available at
  http://www.eclipse.org/legal/epl-v10.html
 */
package ejs.base.sound;

import org.apache.log4j.Logger;

/**
 * Digital sound in a specific encoding
 * @author ejs
 *
 */
public class AudioChunk {
	private static final Logger logger = Logger.getLogger(AudioChunk.class);
	
	private boolean isEmpty;

	public AudioChunk(ISoundView chunk) {
		this(chunk, 1.0);
	}

	/**
	 * @param chunk
	 * @param volume
	 */
	public AudioChunk(ISoundView chunk, double volume) {
		//logger.debug(volume);
		double scale = volume * volume * volume;
		SoundFormat format = chunk.getFormat();
		this.isEmpty = true;
		int length = chunk.getSampleCount();
		if (!chunk.isSilent()) {
			this.soundData = new byte[format.getBytesPerSample() * length];
			if (format.isIntegral()) {
				if (format.getBytesPerSample() == 2) {
					for (int i = 0; i < length; i++) {
						float s = chunk.at(i);
						if (s < -1.0f) s = -1.0f; else if (s > 1.0f) s = 1.0f;
						short samp = (short) (s * scale * 32767);
						if (samp != 0)
							isEmpty = false;
						if (!format.isSigned())
							samp ^= 0x8000;
						//samp &= 0xf000;
						if (format.isBigEndian()) {
							soundData[i*2+1] = (byte) (samp & 0xff);
							soundData[i*2] = (byte) (samp >> 8);
						} else {
							soundData[i*2] = (byte) (samp & 0xff);
							soundData[i*2+1] = (byte) (samp >> 8);
						}
					}
				} else if (format.getBytesPerSample() == 1) {
					for (int i = 0; i < length; i++) {
						float s = chunk.at(i);
						if (s < -1.0f) s = -1.0f; else if (s > 1.0f) s = 1.0f;
						byte samp = (byte) (s * scale * 127);
						if (samp != 0)
							isEmpty = false;
						if (!format.isSigned())
							samp ^= 0x80;
						soundData[i] = samp;
					}
				}
				else {
					logger.error("Not handled: " + format);
				}
			} else {
				// float
				for (int i = 0; i < length; i++) {
					float s = chunk.at(i);
					if (s < -1.0f) s = -1.0f; else if (s > 1.0f) s = 1.0f;

					if (s != 0.0)
						isEmpty = false;
					
					int samp = Float.floatToIntBits(s);
					soundData[i*4] = (byte) (samp & 0xff);
					soundData[i*4+1] = (byte) (samp >> 8);
					soundData[i*4+2] = (byte) (samp >> 16);
					soundData[i*4+3] = (byte) (samp >> 24);
				}
			}
		}
	}

	public byte[] soundData;
	
	/**
	 * @return the isEmpty
	 */
	public boolean isEmpty() {
		return isEmpty;
	}
}