/*
/ Copyright (C) 2009 Risto Känsäkoski- Sesca ISW Ltd
/
/ This file is part of SIP-Applet (www.sesca.com, www.purplescout.com)
/
/ This program is free software; you can redistribute it and/or
/ modify it under the terms of the GNU General Public License
/ as published by the Free Software Foundation; either version 2
/ of the License, or (at your option) any later version.
/
/ This program 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 for more details.
/
/ You should have received a copy of the GNU General Public License
/ along with this program; if not, write to the Free Software
/ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package com.sesca.audio;
public class PCMUCodec implements AudioTranscoder{
int cBias = 0x84;
int cClip = 32635;
static int MuLawCompressTable[] =
{
0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,
4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
};
static int MuLawDecompressTable[] =
{
-32124,-31100,-30076,-29052,-28028,-27004,-25980,-24956,
-23932,-22908,-21884,-20860,-19836,-18812,-17788,-16764,
-15996,-15484,-14972,-14460,-13948,-13436,-12924,-12412,
-11900,-11388,-10876,-10364, -9852, -9340, -8828, -8316,
-7932, -7676, -7420, -7164, -6908, -6652, -6396, -6140,
-5884, -5628, -5372, -5116, -4860, -4604, -4348, -4092,
-3900, -3772, -3644, -3516, -3388, -3260, -3132, -3004,
-2876, -2748, -2620, -2492, -2364, -2236, -2108, -1980,
-1884, -1820, -1756, -1692, -1628, -1564, -1500, -1436,
-1372, -1308, -1244, -1180, -1116, -1052, -988, -924,
-876, -844, -812, -780, -748, -716, -684, -652,
-620, -588, -556, -524, -492, -460, -428, -396,
-372, -356, -340, -324, -308, -292, -276, -260,
-244, -228, -212, -196, -180, -164, -148, -132,
-120, -112, -104, -96, -88, -80, -72, -64,
-56, -48, -40, -32, -24, -16, -8, 0,
32124, 31100, 30076, 29052, 28028, 27004, 25980, 24956,
23932, 22908, 21884, 20860, 19836, 18812, 17788, 16764,
15996, 15484, 14972, 14460, 13948, 13436, 12924, 12412,
11900, 11388, 10876, 10364, 9852, 9340, 8828, 8316,
7932, 7676, 7420, 7164, 6908, 6652, 6396, 6140,
5884, 5628, 5372, 5116, 4860, 4604, 4348, 4092,
3900, 3772, 3644, 3516, 3388, 3260, 3132, 3004,
2876, 2748, 2620, 2492, 2364, 2236, 2108, 1980,
1884, 1820, 1756, 1692, 1628, 1564, 1500, 1436,
1372, 1308, 1244, 1180, 1116, 1052, 988, 924,
876, 844, 812, 780, 748, 716, 684, 652,
620, 588, 556, 524, 492, 460, 428, 396,
372, 356, 340, 324, 308, 292, 276, 260,
244, 228, 212, 196, 180, 164, 148, 132,
120, 112, 104, 96, 88, 80, 72, 64,
56, 48, 40, 32, 24, 16, 8, 0
};
public byte[] encode(byte[] frame){
byte[] encodedFrame=new byte[frame.length/2];
int j=0;
for (int i=0;i<frame.length;i+=2)
{
int sample = (frame[i+1]<<8)+(frame[i]<<0);
int sign = (sample >> 8) & 0x80;
if (sign!=0)
sample = -sample;
if (sample > cClip)
sample = cClip;
sample = (sample + cBias);
int exponent = MuLawCompressTable[(sample>>7) & 0xFF];
int mantissa = (sample >> (exponent+3)) & 0x0F;
int compressedByte = ~ (sign | (exponent << 4) | mantissa);
encodedFrame[j]=(byte)compressedByte;
j++;
}
return encodedFrame;
}
public boolean canEncode() {
// TODO Auto-generated method stub
return true;
}
public boolean canDecode() {
// TODO Auto-generated method stub
return true;
}
public boolean supportsSilenceSuppression() {
// TODO Auto-generated method stub
return false;
}
public byte[] decode(byte[] b) {
int j=0;
byte[] decodedFrame=new byte[b.length*2];
for (int i=0;i<b.length;i++)
{
int x=b[i]& 0xFF;
int sample=MuLawDecompressTable[x];
decodedFrame[j]=(byte) (sample & 0xFF);
decodedFrame[j+1]=(byte) (int)((sample >> 8) & 0xFF);
j+=2;
}
return decodedFrame;
}
public int getBitRate() {
// TODO Auto-generated method stub
return 16;
}
public int getSampleRate() {
// TODO Auto-generated method stub
return 8000;
}
public int getChannels() {
// TODO Auto-generated method stub
return 1;
}
public int getFrameLength() {
// TODO Auto-generated method stub
return 20;
}
public int getFrameSize() {
// TODO Auto-generated method stub
return 160;
}
public int getPayloadType() {
// TODO Auto-generated method stub
return 0;
}
public void init() {
// TODO Auto-generated method stub
}
public boolean supportsPseudoEchoCancellation() {
// TODO Auto-generated method stub
return false;
}
}