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package com.sun.media.sound;

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

import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioFormat.Encoding;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.spi.FormatConversionProvider;

U-law encodes linear data, and decodes u-law data to linear data.
Author:Kara Kytle
/** * U-law encodes linear data, and decodes u-law data to linear data. * * @author Kara Kytle */
public final class UlawCodec extends FormatConversionProvider { /* Tables used for U-law decoding */ private static final byte[] ULAW_TABH = new byte[256]; private static final byte[] ULAW_TABL = new byte[256]; private static final short[] seg_end = { 0xFF, 0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF };
Initializes the decode tables.
/** * Initializes the decode tables. */
static { for (int i=0;i<256;i++) { int ulaw = ~i; int t; ulaw &= 0xFF; t = ((ulaw & 0xf)<<3) + 132; t <<= ((ulaw & 0x70) >> 4); t = ( (ulaw&0x80) != 0 ) ? (132-t) : (t-132); ULAW_TABL[i] = (byte) (t&0xff); ULAW_TABH[i] = (byte) ((t>>8) & 0xff); } } @Override public AudioFormat.Encoding[] getSourceEncodings() { return new Encoding[]{Encoding.ULAW, Encoding.PCM_SIGNED}; } @Override public AudioFormat.Encoding[] getTargetEncodings() { return getSourceEncodings(); } @Override public AudioFormat.Encoding[] getTargetEncodings(AudioFormat sourceFormat){ if( AudioFormat.Encoding.PCM_SIGNED.equals(sourceFormat.getEncoding()) ) { if( sourceFormat.getSampleSizeInBits() == 16 ) { AudioFormat.Encoding[] enc = new AudioFormat.Encoding[1]; enc[0] = AudioFormat.Encoding.ULAW; return enc; } else { return new AudioFormat.Encoding[0]; } } else if (AudioFormat.Encoding.ULAW.equals(sourceFormat.getEncoding())) { 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]; } } @Override public AudioFormat[] getTargetFormats(AudioFormat.Encoding targetEncoding, AudioFormat sourceFormat){ Objects.requireNonNull(targetEncoding); Objects.requireNonNull(sourceFormat); if( (AudioFormat.Encoding.PCM_SIGNED.equals(targetEncoding) && AudioFormat.Encoding.ULAW.equals(sourceFormat.getEncoding())) || (AudioFormat.Encoding.ULAW.equals(targetEncoding) && AudioFormat.Encoding.PCM_SIGNED.equals(sourceFormat.getEncoding()))) { return getOutputFormats(sourceFormat); } else { return new AudioFormat[0]; } } @Override public AudioInputStream getAudioInputStream(AudioFormat.Encoding targetEncoding, AudioInputStream sourceStream){ AudioFormat sourceFormat = sourceStream.getFormat(); AudioFormat.Encoding sourceEncoding = sourceFormat.getEncoding(); if (!isConversionSupported(targetEncoding,sourceStream.getFormat())) { throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString()); } if (sourceEncoding.equals(targetEncoding)) { return sourceStream; } AudioFormat targetFormat = null; if (AudioFormat.Encoding.ULAW.equals(sourceEncoding) && AudioFormat.Encoding.PCM_SIGNED.equals(targetEncoding) ) { targetFormat = new AudioFormat( targetEncoding, sourceFormat.getSampleRate(), 16, sourceFormat.getChannels(), 2*sourceFormat.getChannels(), sourceFormat.getSampleRate(), sourceFormat.isBigEndian()); } else if (AudioFormat.Encoding.PCM_SIGNED.equals(sourceEncoding) && AudioFormat.Encoding.ULAW.equals(targetEncoding)) { 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 getConvertedStream(targetFormat, sourceStream); } @Override public AudioInputStream getAudioInputStream(AudioFormat targetFormat, AudioInputStream sourceStream){ if (!isConversionSupported(targetFormat, sourceStream.getFormat())) throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetFormat.toString()); return getConvertedStream(targetFormat, sourceStream); }
Opens the codec with the specified parameters.
Params:
  • stream – stream from which data to be processed should be read
  • outputFormat – desired data format of the stream after processing
Throws:
Returns:stream from which processed data may be read
/** * 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. */
private AudioInputStream getConvertedStream(AudioFormat outputFormat, AudioInputStream stream) { AudioInputStream cs = null; AudioFormat inputFormat = stream.getFormat(); if( inputFormat.matches(outputFormat) ) { cs = stream; } else { cs = new UlawCodecStream(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.
Returns:array of supported output formats.
/** * 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. */
private AudioFormat[] getOutputFormats(AudioFormat inputFormat) { Vector<AudioFormat> formats = new Vector<>(); AudioFormat format; if ((inputFormat.getSampleSizeInBits() == 16) && AudioFormat.Encoding.PCM_SIGNED.equals(inputFormat.getEncoding())) { format = new AudioFormat(AudioFormat.Encoding.ULAW, inputFormat.getSampleRate(), 8, inputFormat.getChannels(), inputFormat.getChannels(), inputFormat.getSampleRate(), false ); formats.addElement(format); } if (inputFormat.getSampleSizeInBits() == 8 && AudioFormat.Encoding.ULAW.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] = formats.elementAt(i); } return formatArray; } private final class UlawCodecStream extends AudioInputStream { private static final int tempBufferSize = 64; private byte[] tempBuffer = null;
True to encode to u-law, false to decode to linear.
/** * True to encode to u-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; UlawCodecStream(AudioInputStream stream, AudioFormat outputFormat) { super(stream, outputFormat, AudioSystem.NOT_SPECIFIED); AudioFormat inputFormat = stream.getFormat(); // throw an IllegalArgumentException if not ok if (!(isConversionSupported(outputFormat, inputFormat))) { throw new IllegalArgumentException("Unsupported conversion: " + inputFormat.toString() + " to " + outputFormat.toString()); } //$$fb 2002-07-18: fix for 4714846: JavaSound ULAW (8-bit) encoder erroneously depends on endian-ness boolean PCMIsBigEndian; // determine whether we are encoding or decoding if (AudioFormat.Encoding.ULAW.equals(inputFormat.getEncoding())) { encode = false; encodeFormat = inputFormat; decodeFormat = outputFormat; PCMIsBigEndian = outputFormat.isBigEndian(); } else { encode = true; encodeFormat = outputFormat; decodeFormat = inputFormat; PCMIsBigEndian = inputFormat.isBigEndian(); tempBuffer = new byte[tempBufferSize]; } // setup tables according to byte order if (PCMIsBigEndian) { tabByte1 = ULAW_TABH; tabByte2 = ULAW_TABL; highByte = 0; lowByte = 1; } else { tabByte1 = ULAW_TABL; tabByte2 = ULAW_TABH; highByte = 1; lowByte = 0; } // set the AudioInputStream length in frames if we know it if (stream instanceof AudioInputStream) { frameLength = stream.getFrameLength(); } // set framePos to zero framePos = 0; frameSize = inputFormat.getFrameSize(); if (frameSize == AudioSystem.NOT_SPECIFIED) { frameSize = 1; } } /* * $$jb 2/23/99 * Used to determine segment number in uLaw 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.
/** * Note that this won't actually read anything; must read in * two-byte units. */
@Override public int read() throws IOException { byte[] b = new byte[1]; if (read(b, 0, b.length) == 1) { return b[1] & 0xFF; } return -1; } @Override public int read(byte[] b) throws IOException { return read(b, 0, b.length); } @Override 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 BIAS = 0x84; short mask; short seg; 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)( (short) (tempBuffer[i + lowByte]) & 0xFF); /* Get the sign and the magnitude of the value. */ if(sample < 0) { sample = (short) (BIAS - sample); mask = 0x7F; } else { sample += BIAS; mask = 0xFF; } /* Convert the scaled magnitude to segment number. */ seg = search(sample, seg_end, (short) 8); /* * Combine the sign, segment, quantization bits; * and complement the code word. */ if (seg >= 8) { /* out of range, return maximum value. */ enc = (byte) (0x7F ^ mask); } else { enc = (byte) ((seg << 4) | ((sample >> (seg+3)) & 0xF)); 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 on read 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); if(readCount<0) { // EOF or error return readCount; } for (i = off; i < (off + (readCount*2)); i+=2) { b[i] = tabByte1[b[readOffset] & 0xFF]; b[i+1] = tabByte2[b[readOffset] & 0xFF]; readOffset++; } return (i - off); } } @Override public long skip(final long n) throws IOException { // Implementation of this method assumes that we support // encoding/decoding from/to 8/16 bits only return encode ? super.skip(n * 2) / 2 : super.skip(n / 2) * 2; } } // end class UlawCodecStream } // end class ULAW