Back to index...

	/*
	* Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package com.sun.media.sound;

	import java.io.IOException;
	import java.util.Vector;

	import javax.sound.sampled.AudioFormat;
	import javax.sound.sampled.AudioInputStream;
	import javax.sound.sampled.AudioSystem;


	/**
	* A-law encodes linear data, and decodes a-law data to linear data.
	*
	* @author Kara Kytle
	*/
	public final class AlawCodec extends SunCodec {

	/* Tables used for A-law decoding */

	private static final byte[] ALAW_TABH = new byte[256];
	private static final byte[] ALAW_TABL = new byte[256];

	private static final AudioFormat.Encoding[] alawEncodings = { AudioFormat.Encoding.ALAW, AudioFormat.Encoding.PCM_SIGNED };

	private static final short seg_end [] = {0xFF, 0x1FF, 0x3FF,
	0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF};

	/**
	* Initializes the decode tables
	*/
	static {
	for (int i=0;i<256;i++) {
	int input = i ^ 0x55;
	int mantissa = (input & 0xf ) << 4;
	int segment = (input & 0x70) >> 4;
	int value = mantissa+8;

	if(segment>=1)
	value+=0x100;
	if(segment>1)
	value <<= (segment -1);

	if( (input & 0x80)==0 )
	value = -value;

	ALAW_TABL[i] = (byte)value;
	ALAW_TABH[i] = (byte)(value>>8);
	}
	}


	/**
	* Constructs a new ALAW codec object.
	*/
	public AlawCodec() {

	super(alawEncodings, alawEncodings);
	}

	// NEW CODE

	/**
	*/
	public AudioFormat.Encoding[] getTargetEncodings(AudioFormat sourceFormat){

	if( sourceFormat.getEncoding().equals( AudioFormat.Encoding.PCM_SIGNED )) {

	if( sourceFormat.getSampleSizeInBits() == 16 ) {

	AudioFormat.Encoding enc[] = new AudioFormat.Encoding[1];
	enc[0] = AudioFormat.Encoding.ALAW;
	return enc;

	} else {
	return new AudioFormat.Encoding[0];
	}
	} else if( sourceFormat.getEncoding().equals( AudioFormat.Encoding.ALAW ) ) {

	if( sourceFormat.getSampleSizeInBits() == 8 ) {

	AudioFormat.Encoding enc[] = new AudioFormat.Encoding[1];
	enc[0] = AudioFormat.Encoding.PCM_SIGNED;
	return enc;

	} else {
	return new AudioFormat.Encoding[0];
	}

	} else {
	return new AudioFormat.Encoding[0];
	}
	}

	/**
	*/
	public AudioFormat[] getTargetFormats(AudioFormat.Encoding targetEncoding, AudioFormat sourceFormat){
	if( (targetEncoding.equals( AudioFormat.Encoding.PCM_SIGNED ) && sourceFormat.getEncoding().equals( AudioFormat.Encoding.ALAW)) \|\|
	(targetEncoding.equals( AudioFormat.Encoding.ALAW) && sourceFormat.getEncoding().equals( AudioFormat.Encoding.PCM_SIGNED)) ) {
	return getOutputFormats( sourceFormat );
	} else {
	return new AudioFormat[0];
	}
	}

	/**
	*/
	public AudioInputStream getAudioInputStream(AudioFormat.Encoding targetEncoding, AudioInputStream sourceStream){
	AudioFormat sourceFormat = sourceStream.getFormat();
	AudioFormat.Encoding sourceEncoding = sourceFormat.getEncoding();

	if( sourceEncoding.equals( targetEncoding ) ) {
	return sourceStream;
	} else {
	AudioFormat targetFormat = null;
	if( !isConversionSupported(targetEncoding,sourceStream.getFormat()) ) {
	throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString());
	}
	if( sourceEncoding.equals( AudioFormat.Encoding.ALAW ) &&
	targetEncoding.equals( AudioFormat.Encoding.PCM_SIGNED ) ) {

	targetFormat = new AudioFormat( targetEncoding,
	sourceFormat.getSampleRate(),
	16,
	sourceFormat.getChannels(),
	2*sourceFormat.getChannels(),
	sourceFormat.getSampleRate(),
	sourceFormat.isBigEndian());

	} else if( sourceEncoding.equals( AudioFormat.Encoding.PCM_SIGNED ) &&
	targetEncoding.equals( AudioFormat.Encoding.ALAW ) ) {

	targetFormat = new AudioFormat( targetEncoding,
	sourceFormat.getSampleRate(),
	8,
	sourceFormat.getChannels(),
	sourceFormat.getChannels(),
	sourceFormat.getSampleRate(),
	false);
	} else {
	throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString());
	}
	return getAudioInputStream( targetFormat, sourceStream );
	}
	}

	/**
	* use old code...
	*/
	public AudioInputStream getAudioInputStream(AudioFormat targetFormat, AudioInputStream sourceStream){
	return getConvertedStream( targetFormat, sourceStream );
	}


	// OLD CODE


	/**
	* Opens the codec with the specified parameters.
	* @param stream stream from which data to be processed should be read
	* @param outputFormat desired data format of the stream after processing
	* @return stream from which processed data may be read
	* @throws IllegalArgumentException if the format combination supplied is
	* not supported.
	*/
	/* public AudioInputStream getConvertedStream(AudioFormat outputFormat, AudioInputStream stream) { */
	private AudioInputStream getConvertedStream(AudioFormat outputFormat, AudioInputStream stream) {

	AudioInputStream cs = null;
	AudioFormat inputFormat = stream.getFormat();

	if( inputFormat.matches(outputFormat) ) {
	cs = stream;
	} else {
	cs = (AudioInputStream) (new AlawCodecStream(stream, outputFormat));
	}

	return cs;
	}

	/**
	* Obtains the set of output formats supported by the codec
	* given a particular input format.
	* If no output formats are supported for this input format,
	* returns an array of length 0.
	* @return array of supported output formats.
	*/
	/* public AudioFormat[] getOutputFormats(AudioFormat inputFormat) { */
	private AudioFormat[] getOutputFormats(AudioFormat inputFormat) {


	Vector formats = new Vector();
	AudioFormat format;

	if ( AudioFormat.Encoding.PCM_SIGNED.equals(inputFormat.getEncoding())) {
	format = new AudioFormat(AudioFormat.Encoding.ALAW,
	inputFormat.getSampleRate(),
	8,
	inputFormat.getChannels(),
	inputFormat.getChannels(),
	inputFormat.getSampleRate(),
	false );
	formats.addElement(format);
	}

	if (AudioFormat.Encoding.ALAW.equals(inputFormat.getEncoding())) {
	format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
	inputFormat.getSampleRate(),
	16,
	inputFormat.getChannels(),
	inputFormat.getChannels()*2,
	inputFormat.getSampleRate(),
	false );
	formats.addElement(format);
	format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
	inputFormat.getSampleRate(),
	16,
	inputFormat.getChannels(),
	inputFormat.getChannels()*2,
	inputFormat.getSampleRate(),
	true );
	formats.addElement(format);
	}

	AudioFormat[] formatArray = new AudioFormat[formats.size()];
	for (int i = 0; i < formatArray.length; i++) {
	formatArray[i] = (AudioFormat)(formats.elementAt(i));
	}
	return formatArray;
	}


	final class AlawCodecStream extends AudioInputStream {

	// tempBuffer required only for encoding (when encode is true)
	private static final int tempBufferSize = 64;
	private byte tempBuffer [] = null;

	/**
	* True to encode to a-law, false to decode to linear
	*/
	boolean encode = false;

	AudioFormat encodeFormat;
	AudioFormat decodeFormat;

	byte tabByte1[] = null;
	byte tabByte2[] = null;
	int highByte = 0;
	int lowByte = 1;

	AlawCodecStream(AudioInputStream stream, AudioFormat outputFormat) {

	super(stream, outputFormat, -1);

	AudioFormat inputFormat = stream.getFormat();

	// throw an IllegalArgumentException if not ok
	if ( ! (isConversionSupported(outputFormat, inputFormat)) ) {

	throw new IllegalArgumentException("Unsupported conversion: " + inputFormat.toString() + " to " + outputFormat.toString());
	}

	//$$fb 2002-07-18: fix for 4714846: JavaSound ULAW (8-bit) encoder erroneously depends on endian-ness
	boolean PCMIsBigEndian;

	// determine whether we are encoding or decoding
	if (AudioFormat.Encoding.ALAW.equals(inputFormat.getEncoding())) {
	encode = false;
	encodeFormat = inputFormat;
	decodeFormat = outputFormat;
	PCMIsBigEndian = outputFormat.isBigEndian();
	} else {
	encode = true;
	encodeFormat = outputFormat;
	decodeFormat = inputFormat;
	PCMIsBigEndian = inputFormat.isBigEndian();
	tempBuffer = new byte[tempBufferSize];
	}

	if (PCMIsBigEndian) {
	tabByte1 = ALAW_TABH;
	tabByte2 = ALAW_TABL;
	highByte = 0;
	lowByte = 1;
	} else {
	tabByte1 = ALAW_TABL;
	tabByte2 = ALAW_TABH;
	highByte = 1;
	lowByte = 0;
	}

	// set the AudioInputStream length in frames if we know it
	if (stream instanceof AudioInputStream) {
	frameLength = ((AudioInputStream)stream).getFrameLength();
	}

	// set framePos to zero
	framePos = 0;
	frameSize = inputFormat.getFrameSize();
	if( frameSize==AudioSystem.NOT_SPECIFIED ) {
	frameSize=1;
	}
	}


	/*
	* $$jb 2/23/99
	* Used to determine segment number in aLaw encoding
	*/
	private short search(short val, short table[], short size) {
	for(short i = 0; i < size; i++) {
	if (val <= table[i]) { return i; }
	}
	return size;
	}

	/**
	* Note that this won't actually read anything; must read in
	* two-byte units.
	*/
	public int read() throws IOException {

	byte[] b = new byte[1];
	return (int)read(b, 0, b.length);
	}


	public int read(byte[] b) throws IOException {

	return read(b, 0, b.length);
	}

	public int read(byte[] b, int off, int len) throws IOException {

	// don't read fractional frames
	if( len%frameSize != 0 ) {
	len -= (len%frameSize);
	}

	if (encode) {

	short QUANT_MASK = 0xF;
	short SEG_SHIFT = 4;
	short mask;
	short seg;
	int adj;
	int i;

	short sample;
	byte enc;

	int readCount = 0;
	int currentPos = off;
	int readLeft = len*2;
	int readLen = ( (readLeft>tempBufferSize) ? tempBufferSize : readLeft );

	while ((readCount = super.read(tempBuffer,0,readLen))>0) {

	for (i = 0; i < readCount; i+=2) {

	/* Get the sample from the tempBuffer */
	sample = (short)(( (tempBuffer[i + highByte]) << 8) & 0xFF00);
	sample \|= (short)( (tempBuffer[i + lowByte]) & 0xFF);

	if(sample >= 0) {
	mask = 0xD5;
	} else {
	mask = 0x55;
	sample = (short)(-sample - 8);
	}
	/* Convert the scaled magnitude to segment number. */
	seg = search(sample, seg_end, (short) 8);
	/*
	* Combine the sign, segment, quantization bits
	*/
	if (seg >= 8) { /* out of range, return maximum value. */
	enc = (byte) (0x7F ^ mask);
	} else {
	enc = (byte) (seg << SEG_SHIFT);
	if(seg < 2) {
	enc \|= (byte) ( (sample >> 4) & QUANT_MASK);
	} else {
	enc \|= (byte) ( (sample >> (seg + 3)) & QUANT_MASK );
	}
	enc ^= mask;
	}
	/* Now put the encoded sample where it belongs */
	b[currentPos] = enc;
	currentPos++;
	}
	/* And update pointers and counters for next iteration */
	readLeft -= readCount;
	readLen = ( (readLeft>tempBufferSize) ? tempBufferSize : readLeft );
	}

	if( currentPos==off && readCount<0 ) { // EOF or error
	return readCount;
	}

	return (currentPos - off); /* Number of bytes written to new buffer */

	} else {

	int i;
	int readLen = len/2;
	int readOffset = off + len/2;
	int readCount = super.read(b, readOffset, readLen);

	for (i = off; i < (off + (readCount*2)); i+=2) {
	b[i] = (byte)tabByte1[b[readOffset] & 0xFF];
	b[i+1] = (byte)tabByte2[b[readOffset] & 0xFF];
	readOffset++;
	}

	if( readCount<0 ) { // EOF or error
	return readCount;
	}

	return (i - off);
	}
	}
	} // end class AlawCodecStream
	} // end class ALAW

Back to index...