package org.asteriskjava.iax.audio.javasound;
import org.asteriskjava.iax.protocol.Log;
import org.asteriskjava.iax.protocol.VoiceFrame;
import org.asteriskjava.iax.util.ByteBuffer;
import javax.sound.sampled.AudioFormat;
/**
* Description of the Class
*/
public class AudioAlaw extends AbstractAudio {
AudioFormat _alawFormat;
private int _ss;
/**
* Constructor for the AudioAlaw object
*/
public AudioAlaw(Audio8k a8) {
_a8 = a8;
_ss = _a8.getSampSz();
Log.debug("8k buffer size = " + _ss);
_obuff = new byte[_ss];
_ibuff = new byte[_ss];
}
//////////////////// ALAW ////////////////////////////
/*
This source code is a product of Sun Microsystems, Inc. and is provided
for unrestricted use. Users may copy or modify this source code without
charge.
linear2alaw() - Convert a 16-bit linear PCM value to 8-bit A-law
linear2alaw() accepts an 16-bit integer and encodes it as A-law data.
Linear Input Code Compressed Code
------------------------ ---------------
0000000wxyza 000wxyz
0000001wxyza 001wxyz
000001wxyzab 010wxyz
00001wxyzabc 011wxyz
0001wxyzabcd 100wxyz
001wxyzabcde 101wxyz
01wxyzabcdef 110wxyz
1wxyzabcdefg 111wxyz
For further information see John C. Bellamy's Digital Telephony, 1982,
John Wiley & Sons, pps 98-111 and 472-476.
*/
/* Quantization field mask. */
private final static byte QUANT_MASK = 0xf;
/* Left shift for segment number. */
private final static byte SEG_SHIFT = 4;
private final static short[] seg_end = {
0xFF, 0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF
};
/**
* Description of the Method
*
* @param pcm_val Description of Parameter
* @return Description of the Returned Value
*/
public static byte linear2alaw(short pcm_val) {
/* 2's complement (16-bit range) */
byte mask;
byte seg = 8;
byte aval;
if (pcm_val >= 0) {
mask = (byte) 0xD5;
/* sign (7th) bit = 1 */
} else {
mask = 0x55;
/* sign bit = 0 */
pcm_val = (short) (-pcm_val - 8);
}
/*
Convert the scaled magnitude to segment number.
*/
for (int i = 0; i < 8; i++) {
if (pcm_val <= seg_end[i]) {
seg = (byte) i;
break;
}
}
/* Combine the sign, segment, and quantization bits. */
if (seg >= 8) {
/* out of range, return maximum value. */
return (byte) ((0x7F ^ mask) & 0xFF);
} else {
aval = (byte) (seg << SEG_SHIFT);
if (seg < 2) {
aval |= (pcm_val >> 4) & QUANT_MASK;
} else {
aval |= (pcm_val >> (seg + 3)) & QUANT_MASK;
}
return (byte) ((aval ^ mask) & 0xFF);
}
}
private static short[] a2l = {
-5504, -5248, -6016, -5760, -4480, -4224, -4992, -4736,
-7552, -7296, -8064, -7808, -6528, -6272, -7040, -6784,
-2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368,
-3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392,
-22016, -20992, -24064, -23040, -17920, -16896, -19968, -18944,
-30208, -29184, -32256, -31232, -26112, -25088, -28160, -27136,
-11008, -10496, -12032, -11520, -8960, -8448, -9984, -9472,
-15104, -14592, -16128, -15616, -13056, -12544, -14080, -13568,
-344, -328, -376, -360, -280, -264, -312, -296,
-472, -456, -504, -488, -408, -392, -440, -424,
-88, -72, -120, -104, -24, -8, -56, -40,
-216, -200, -248, -232, -152, -136, -184, -168,
-1376, -1312, -1504, -1440, -1120, -1056, -1248, -1184,
-1888, -1824, -2016, -1952, -1632, -1568, -1760, -1696,
-688, -656, -752, -720, -560, -528, -624, -592,
-944, -912, -1008, -976, -816, -784, -880, -848,
5504, 5248, 6016, 5760, 4480, 4224, 4992, 4736,
7552, 7296, 8064, 7808, 6528, 6272, 7040, 6784,
2752, 2624, 3008, 2880, 2240, 2112, 2496, 2368,
3776, 3648, 4032, 3904, 3264, 3136, 3520, 3392,
22016, 20992, 24064, 23040, 17920, 16896, 19968, 18944,
30208, 29184, 32256, 31232, 26112, 25088, 28160, 27136,
11008, 10496, 12032, 11520, 8960, 8448, 9984, 9472,
15104, 14592, 16128, 15616, 13056, 12544, 14080, 13568,
344, 328, 376, 360, 280, 264, 312, 296,
472, 456, 504, 488, 408, 392, 440, 424,
88, 72, 120, 104, 24, 8, 56, 40,
216, 200, 248, 232, 152, 136, 184, 168,
1376, 1312, 1504, 1440, 1120, 1056, 1248, 1184,
1888, 1824, 2016, 1952, 1632, 1568, 1760, 1696,
688, 656, 752, 720, 560, 528, 624, 592,
944, 912, 1008, 976, 816, 784, 880, 848
};
/**
* Description of the Method
*
* @param ulawbyte Description of Parameter
* @return Description of the Returned Value
*/
public static short alaw2linear(byte ulawbyte) {
return a2l[ulawbyte & 0xFF];
}
/**
* Gets the audioFormat attribute of the AudioAlaw object
*
* @return The audioFormat value
*/
protected AudioFormat getAudioFormat() {
if (_alawFormat == null) {
try {
_alawFormat = new AudioFormat(
AudioFormat.Encoding.ALAW,
8000.0F, // sampleRate
8, // sampleSizeInBits
1, // channels
1, // frameSize
8000.0F, // frameRate
false);// bigEndian
} catch (Exception x) {
Log.warn(x.getMessage());
}
}
return _alawFormat;
}
/**
* changedProps
*/
@Override
public void changedProps() {
}
/**
* getSampSz
*
* @return int
*/
@Override
public int getSampSz() {
return 160;
}
/**
* Description of the Method
*
* @param in Description of Parameter
* @param out Description of Parameter
*/
@Override
public void convertToLin(byte[] in, byte[] out) {
convert(in, out);
}
/**
* Description of the Method
*
* @param in Description of Parameter
* @param out Description of Parameter
*/
@Override
public void convertFromLin(byte[] in, byte[] out) {
ByteBuffer bb = ByteBuffer.wrap(in);
for (int i = 0; i < in.length / 2; i++) {
short s = bb.getShort();
out[i] = linear2alaw(s);
}
}
/**
* convert
*
* @param in byte[]
* @param out byte[]
*/
public static void convert(byte[] in, byte[] out) {
ByteBuffer bb = ByteBuffer.wrap(out);
for (int i = 0; i < in.length; i++) {
short s = alaw2linear(in[i]);
bb.putShort(s);
}
}
/**
* getFormatBit
*
* @return int
*/
@Override
public int getFormatBit() {
return VoiceFrame.ALAW_BIT;
}
}