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5
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1 /*
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2 * SpanDSP - a series of DSP components for telephony
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3 *
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4 * g726.c - The ITU G.726 codec.
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5 *
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6 * Written by Steve Underwood <steveu@coppice.org>
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7 *
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8 * Copyright (C) 2006 Steve Underwood
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9 *
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10 * All rights reserved.
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11 *
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12 * This program is free software; you can redistribute it and/or modify
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13 * it under the terms of the GNU General Public License version 2, as
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14 * published by the Free Software Foundation.
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15 *
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16 * This program is distributed in the hope that it will be useful,
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17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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19 * GNU General Public License for more details.
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20 *
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21 * You should have received a copy of the GNU General Public License
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22 * along with this program; if not, write to the Free Software
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23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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24 *
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25 * Based on G.721/G.723 code which is:
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26 *
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27 * This source code is a product of Sun Microsystems, Inc. and is provided
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28 * for unrestricted use. Users may copy or modify this source code without
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29 * charge.
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30 *
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31 * SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING
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32 * THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
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33 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
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34 *
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35 * Sun source code is provided with no support and without any obligation on
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36 * the part of Sun Microsystems, Inc. to assist in its use, correction,
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37 * modification or enhancement.
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38 *
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39 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
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40 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE
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41 * OR ANY PART THEREOF.
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42 *
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43 * In no event will Sun Microsystems, Inc. be liable for any lost revenue
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44 * or profits or other special, indirect and consequential damages, even if
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45 * Sun has been advised of the possibility of such damages.
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46 *
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47 * Sun Microsystems, Inc.
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48 * 2550 Garcia Avenue
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49 * Mountain View, California 94043
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50 *
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51 * $Id: g726.c,v 1.17 2006/11/19 14:07:24 steveu Exp $
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52 */
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53
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54 /*! \file */
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55
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56 #ifdef HAVE_CONFIG_H
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57 #include <config.h>
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58 #endif
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59
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60 #include <inttypes.h>
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61 #include <memory.h>
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62 #include <stdlib.h>
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63 #if defined(HAVE_TGMATH_H)
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64 #include <tgmath.h>
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65 #endif
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66 #if defined(HAVE_MATH_H)
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67 #include <math.h>
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68 #endif
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69
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70 #include "spandsp/telephony.h"
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71 #include "spandsp/dc_restore.h"
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72 #include "spandsp/bitstream.h"
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73 #include "spandsp/bit_operations.h"
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74 #include "spandsp/g711.h"
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75 #include "spandsp/g726.h"
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76
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77 /*
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78 * Maps G.726_16 code word to reconstructed scale factor normalized log
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79 * magnitude values.
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80 */
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81 static const int g726_16_dqlntab[4] =
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82 {
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83 116, 365, 365, 116
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84 };
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85
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86 /* Maps G.726_16 code word to log of scale factor multiplier. */
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87 static const int g726_16_witab[4] =
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88 {
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89 -704, 14048, 14048, -704
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90 };
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91
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92 /*
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93 * Maps G.726_16 code words to a set of values whose long and short
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94 * term averages are computed and then compared to give an indication
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95 * how stationary (steady state) the signal is.
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96 */
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97 static const int g726_16_fitab[4] =
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98 {
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99 0x000, 0xE00, 0xE00, 0x000
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100 };
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101
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102 static const int qtab_726_16[1] =
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103 {
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104 261
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105 };
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106
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107 /*
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108 * Maps G.726_24 code word to reconstructed scale factor normalized log
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109 * magnitude values.
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110 */
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111 static const int g726_24_dqlntab[8] =
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112 {
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113 -2048, 135, 273, 373, 373, 273, 135, -2048
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114 };
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115
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116 /* Maps G.726_24 code word to log of scale factor multiplier. */
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117 static const int g726_24_witab[8] =
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118 {
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119 -128, 960, 4384, 18624, 18624, 4384, 960, -128
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120 };
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121
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122 /*
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123 * Maps G.726_24 code words to a set of values whose long and short
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124 * term averages are computed and then compared to give an indication
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125 * how stationary (steady state) the signal is.
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126 */
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127 static const int g726_24_fitab[8] =
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128 {
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129 0x000, 0x200, 0x400, 0xE00, 0xE00, 0x400, 0x200, 0x000
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130 };
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131
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132 static const int qtab_726_24[3] =
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133 {
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134 8, 218, 331
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135 };
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136
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137 /*
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138 * Maps G.726_32 code word to reconstructed scale factor normalized log
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139 * magnitude values.
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140 */
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141 static const int g726_32_dqlntab[16] =
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142 {
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143 -2048, 4, 135, 213, 273, 323, 373, 425,
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144 425, 373, 323, 273, 213, 135, 4, -2048
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145 };
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146
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147 /* Maps G.726_32 code word to log of scale factor multiplier. */
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148 static const int g726_32_witab[16] =
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149 {
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150 -384, 576, 1312, 2048, 3584, 6336, 11360, 35904,
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151 35904, 11360, 6336, 3584, 2048, 1312, 576, -384
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152 };
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153
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154 /*
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155 * Maps G.726_32 code words to a set of values whose long and short
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156 * term averages are computed and then compared to give an indication
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157 * how stationary (steady state) the signal is.
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158 */
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159 static const int g726_32_fitab[16] =
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160 {
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161 0x000, 0x000, 0x000, 0x200, 0x200, 0x200, 0x600, 0xE00,
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162 0xE00, 0x600, 0x200, 0x200, 0x200, 0x000, 0x000, 0x000
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163 };
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164
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165 static const int qtab_726_32[7] =
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166 {
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167 -124, 80, 178, 246, 300, 349, 400
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168 };
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169
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170 /*
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171 * Maps G.726_40 code word to ructeconstructed scale factor normalized log
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172 * magnitude values.
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173 */
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174 static const int g726_40_dqlntab[32] =
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175 {
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176 -2048, -66, 28, 104, 169, 224, 274, 318,
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177 358, 395, 429, 459, 488, 514, 539, 566,
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178 566, 539, 514, 488, 459, 429, 395, 358,
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179 318, 274, 224, 169, 104, 28, -66, -2048
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180 };
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181
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182 /* Maps G.726_40 code word to log of scale factor multiplier. */
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183 static const int g726_40_witab[32] =
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184 {
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185 448, 448, 768, 1248, 1280, 1312, 1856, 3200,
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186 4512, 5728, 7008, 8960, 11456, 14080, 16928, 22272,
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187 22272, 16928, 14080, 11456, 8960, 7008, 5728, 4512,
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188 3200, 1856, 1312, 1280, 1248, 768, 448, 448
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189 };
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190
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191 /*
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192 * Maps G.726_40 code words to a set of values whose long and short
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193 * term averages are computed and then compared to give an indication
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194 * how stationary (steady state) the signal is.
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195 */
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196 static const int g726_40_fitab[32] =
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197 {
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198 0x000, 0x000, 0x000, 0x000, 0x000, 0x200, 0x200, 0x200,
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199 0x200, 0x200, 0x400, 0x600, 0x800, 0xA00, 0xC00, 0xC00,
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200 0xC00, 0xC00, 0xA00, 0x800, 0x600, 0x400, 0x200, 0x200,
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201 0x200, 0x200, 0x200, 0x000, 0x000, 0x000, 0x000, 0x000
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202 };
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203
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204 static const int qtab_726_40[15] =
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205 {
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206 -122, -16, 68, 139, 198, 250, 298, 339,
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207 378, 413, 445, 475, 502, 528, 553
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208 };
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209
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210 /*
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211 * returns the integer product of the 14-bit integer "an" and
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212 * "floating point" representation (4-bit exponent, 6-bit mantessa) "srn".
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213 */
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214 static int16_t fmult(int16_t an, int16_t srn)
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215 {
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216 int16_t anmag;
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217 int16_t anexp;
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218 int16_t anmant;
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219 int16_t wanexp;
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220 int16_t wanmant;
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221 int16_t retval;
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222
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223 anmag = (an > 0) ? an : ((-an) & 0x1FFF);
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224 anexp = (int16_t) (top_bit(anmag) - 5);
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225 anmant = (anmag == 0) ? 32 : (anexp >= 0) ? (anmag >> anexp) : (anmag << -anexp);
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226 wanexp = anexp + ((srn >> 6) & 0xF) - 13;
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227
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228 wanmant = (anmant*(srn & 0x3F) + 0x30) >> 4;
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229 retval = (wanexp >= 0) ? ((wanmant << wanexp) & 0x7FFF) : (wanmant >> -wanexp);
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230
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231 return (((an ^ srn) < 0) ? -retval : retval);
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232 }
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233 /*- End of function --------------------------------------------------------*/
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234
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235 /*
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236 * Compute the estimated signal from the 6-zero predictor.
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237 */
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238 static __inline__ int16_t predictor_zero(g726_state_t *s)
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239 {
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240 int i;
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241 int sezi;
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242
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243 sezi = fmult(s->b[0] >> 2, s->dq[0]);
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244 /* ACCUM */
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245 for (i = 1; i < 6; i++)
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246 sezi += fmult(s->b[i] >> 2, s->dq[i]);
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247 return (int16_t) sezi;
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248 }
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249 /*- End of function --------------------------------------------------------*/
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250
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251 /*
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252 * Computes the estimated signal from the 2-pole predictor.
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253 */
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254 static __inline__ int16_t predictor_pole(g726_state_t *s)
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255 {
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256 return (fmult(s->a[1] >> 2, s->sr[1]) + fmult(s->a[0] >> 2, s->sr[0]));
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257 }
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258 /*- End of function --------------------------------------------------------*/
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259
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260 /*
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261 * Computes the quantization step size of the adaptive quantizer.
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262 */
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263 static int step_size(g726_state_t *s)
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264 {
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265 int y;
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266 int dif;
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267 int al;
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268
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269 if (s->ap >= 256)
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270 return s->yu;
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271 y = s->yl >> 6;
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272 dif = s->yu - y;
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273 al = s->ap >> 2;
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274 if (dif > 0)
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275 y += (dif*al) >> 6;
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276 else if (dif < 0)
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277 y += (dif*al + 0x3F) >> 6;
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278 return y;
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279 }
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280 /*- End of function --------------------------------------------------------*/
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281
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282 /*
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283 * Given a raw sample, 'd', of the difference signal and a
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284 * quantization step size scale factor, 'y', this routine returns the
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285 * ADPCM codeword to which that sample gets quantized. The step
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286 * size scale factor division operation is done in the log base 2 domain
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287 * as a subtraction.
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288 */
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289 static int16_t quantize(int d, /* Raw difference signal sample */
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290 int y, /* Step size multiplier */
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291 const int table[], /* quantization table */
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292 int quantizer_states) /* table size of int16_t integers */
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293 {
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294 int16_t dqm; /* Magnitude of 'd' */
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295 int16_t exp; /* Integer part of base 2 log of 'd' */
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296 int16_t mant; /* Fractional part of base 2 log */
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297 int16_t dl; /* Log of magnitude of 'd' */
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298 int16_t dln; /* Step size scale factor normalized log */
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299 int i;
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300 int size;
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301
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302 /*
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303 * LOG
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304 *
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305 * Compute base 2 log of 'd', and store in 'dl'.
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306 */
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307 dqm = (int16_t) abs(d);
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308 exp = (int16_t) (top_bit(dqm >> 1) + 1);
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309 /* Fractional portion. */
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310 mant = ((dqm << 7) >> exp) & 0x7F;
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311 dl = (exp << 7) + mant;
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312
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313 /*
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314 * SUBTB
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315 *
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316 * "Divide" by step size multiplier.
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317 */
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318 dln = dl - (int16_t) (y >> 2);
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319
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320 /*
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321 * QUAN
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322 *
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323 * Search for codword i for 'dln'.
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324 */
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325 size = (quantizer_states - 1) >> 1;
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326 for (i = 0; i < size; i++)
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327 {
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328 if (dln < table[i])
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329 break;
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330 }
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331 if (d < 0)
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332 {
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333 /* Take 1's complement of i */
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334 return (int16_t) ((size << 1) + 1 - i);
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335 }
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336 if (i == 0 && (quantizer_states & 1))
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337 {
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338 /* Zero is only valid if there are an even number of states, so
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339 take the 1's complement if the code is zero. */
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340 return (int16_t) quantizer_states;
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341 }
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342 return (int16_t) i;
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343 }
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344 /*- End of function --------------------------------------------------------*/
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345
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346 /*
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347 * Returns reconstructed difference signal 'dq' obtained from
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348 * codeword 'i' and quantization step size scale factor 'y'.
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349 * Multiplication is performed in log base 2 domain as addition.
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350 */
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351 static int16_t reconstruct(int sign, /* 0 for non-negative value */
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352 int dqln, /* G.72x codeword */
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353 int y) /* Step size multiplier */
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354 {
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355 int16_t dql; /* Log of 'dq' magnitude */
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356 int16_t dex; /* Integer part of log */
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357 int16_t dqt;
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358 int16_t dq; /* Reconstructed difference signal sample */
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359
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360 dql = (int16_t) (dqln + (y >> 2)); /* ADDA */
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361
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362 if (dql < 0)
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363 return ((sign) ? -0x8000 : 0);
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364 /* ANTILOG */
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365 dex = (dql >> 7) & 15;
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366 dqt = 128 + (dql & 127);
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367 dq = (dqt << 7) >> (14 - dex);
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368 return ((sign) ? (dq - 0x8000) : dq);
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369 }
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370 /*- End of function --------------------------------------------------------*/
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371
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372 /*
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373 * updates the state variables for each output code
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374 */
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375 static void update(g726_state_t *s,
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376 int y, /* quantizer step size */
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377 int wi, /* scale factor multiplier */
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378 int fi, /* for long/short term energies */
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379 int dq, /* quantized prediction difference */
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380 int sr, /* reconstructed signal */
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381 int dqsez) /* difference from 2-pole predictor */
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382 {
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383 int16_t mag;
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384 int16_t exp;
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385 int16_t a2p; /* LIMC */
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386 int16_t a1ul; /* UPA1 */
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387 int16_t pks1; /* UPA2 */
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388 int16_t fa1;
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389 int16_t ylint;
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390 int16_t dqthr;
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391 int16_t ylfrac;
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392 int16_t thr;
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393 int16_t pk0;
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394 int i;
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395 int tr;
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396
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397 a2p = 0;
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398 /* Needed in updating predictor poles */
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399 pk0 = (dqsez < 0) ? 1 : 0;
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400
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|
|
401 /* prediction difference magnitude */
|
|
|
402 mag = (int16_t) (dq & 0x7FFF);
|
|
|
403 /* TRANS */
|
|
|
404 ylint = (int16_t) (s->yl >> 15); /* exponent part of yl */
|
|
|
405 ylfrac = (int16_t) ((s->yl >> 10) & 0x1F); /* fractional part of yl */
|
|
|
406 /* Limit threshold to 31 << 10 */
|
|
|
407 thr = (ylint > 9) ? (31 << 10) : ((32 + ylfrac) << ylint);
|
|
|
408 dqthr = (thr + (thr >> 1)) >> 1; /* dqthr = 0.75 * thr */
|
|
|
409 if (!s->td) /* signal supposed voice */
|
|
|
410 tr = FALSE;
|
|
|
411 else if (mag <= dqthr) /* supposed data, but small mag */
|
|
|
412 tr = FALSE; /* treated as voice */
|
|
|
413 else /* signal is data (modem) */
|
|
|
414 tr = TRUE;
|
|
|
415
|
|
|
416 /*
|
|
|
417 * Quantizer scale factor adaptation.
|
|
|
418 */
|
|
|
419
|
|
|
420 /* FUNCTW & FILTD & DELAY */
|
|
|
421 /* update non-steady state step size multiplier */
|
|
|
422 s->yu = (int16_t) (y + ((wi - y) >> 5));
|
|
|
423
|
|
|
424 /* LIMB */
|
|
|
425 if (s->yu < 544)
|
|
|
426 s->yu = 544;
|
|
|
427 else if (s->yu > 5120)
|
|
|
428 s->yu = 5120;
|
|
|
429
|
|
|
430 /* FILTE & DELAY */
|
|
|
431 /* update steady state step size multiplier */
|
|
|
432 s->yl += s->yu + ((-s->yl) >> 6);
|
|
|
433
|
|
|
434 /*
|
|
|
435 * Adaptive predictor coefficients.
|
|
|
436 */
|
|
|
437 if (tr)
|
|
|
438 {
|
|
|
439 /* Reset the a's and b's for a modem signal */
|
|
|
440 s->a[0] = 0;
|
|
|
441 s->a[1] = 0;
|
|
|
442 s->b[0] = 0;
|
|
|
443 s->b[1] = 0;
|
|
|
444 s->b[2] = 0;
|
|
|
445 s->b[3] = 0;
|
|
|
446 s->b[4] = 0;
|
|
|
447 s->b[5] = 0;
|
|
|
448 }
|
|
|
449 else
|
|
|
450 {
|
|
|
451 /* Update the a's and b's */
|
|
|
452 /* UPA2 */
|
|
|
453 pks1 = pk0 ^ s->pk[0];
|
|
|
454
|
|
|
455 /* Update predictor pole a[1] */
|
|
|
456 a2p = s->a[1] - (s->a[1] >> 7);
|
|
|
457 if (dqsez != 0)
|
|
|
458 {
|
|
|
459 fa1 = (pks1) ? s->a[0] : -s->a[0];
|
|
|
460 /* a2p = function of fa1 */
|
|
|
461 if (fa1 < -8191)
|
|
|
462 a2p -= 0x100;
|
|
|
463 else if (fa1 > 8191)
|
|
|
464 a2p += 0xFF;
|
|
|
465 else
|
|
|
466 a2p += fa1 >> 5;
|
|
|
467
|
|
|
468 if (pk0 ^ s->pk[1])
|
|
|
469 {
|
|
|
470 /* LIMC */
|
|
|
471 if (a2p <= -12160)
|
|
|
472 a2p = -12288;
|
|
|
473 else if (a2p >= 12416)
|
|
|
474 a2p = 12288;
|
|
|
475 else
|
|
|
476 a2p -= 0x80;
|
|
|
477 }
|
|
|
478 else if (a2p <= -12416)
|
|
|
479 a2p = -12288;
|
|
|
480 else if (a2p >= 12160)
|
|
|
481 a2p = 12288;
|
|
|
482 else
|
|
|
483 a2p += 0x80;
|
|
|
484 }
|
|
|
485
|
|
|
486 /* TRIGB & DELAY */
|
|
|
487 s->a[1] = a2p;
|
|
|
488
|
|
|
489 /* UPA1 */
|
|
|
490 /* Update predictor pole a[0] */
|
|
|
491 s->a[0] -= s->a[0] >> 8;
|
|
|
492 if (dqsez != 0)
|
|
|
493 {
|
|
|
494 if (pks1 == 0)
|
|
|
495 s->a[0] += 192;
|
|
|
496 else
|
|
|
497 s->a[0] -= 192;
|
|
|
498 }
|
|
|
499 /* LIMD */
|
|
|
500 a1ul = 15360 - a2p;
|
|
|
501 if (s->a[0] < -a1ul)
|
|
|
502 s->a[0] = -a1ul;
|
|
|
503 else if (s->a[0] > a1ul)
|
|
|
504 s->a[0] = a1ul;
|
|
|
505
|
|
|
506 /* UPB : update predictor zeros b[6] */
|
|
|
507 for (i = 0; i < 6; i++)
|
|
|
508 {
|
|
|
509 /* Distinguish 40Kbps mode from the others */
|
|
|
510 s->b[i] -= s->b[i] >> ((s->bits_per_sample == 5) ? 9 : 8);
|
|
|
511 if (dq & 0x7FFF)
|
|
|
512 {
|
|
|
513 /* XOR */
|
|
|
514 if ((dq ^ s->dq[i]) >= 0)
|
|
|
515 s->b[i] += 128;
|
|
|
516 else
|
|
|
517 s->b[i] -= 128;
|
|
|
518 }
|
|
|
519 }
|
|
|
520 }
|
|
|
521
|
|
|
522 for (i = 5; i > 0; i--)
|
|
|
523 s->dq[i] = s->dq[i - 1];
|
|
|
524 /* FLOAT A : convert dq[0] to 4-bit exp, 6-bit mantissa f.p. */
|
|
|
525 if (mag == 0)
|
|
|
526 {
|
|
|
527 s->dq[0] = (dq >= 0) ? 0x20 : 0xFC20;
|
|
|
528 }
|
|
|
529 else
|
|
|
530 {
|
|
|
531 exp = (int16_t) (top_bit(mag) + 1);
|
|
|
532 s->dq[0] = (dq >= 0)
|
|
|
533 ? ((exp << 6) + ((mag << 6) >> exp))
|
|
|
534 : ((exp << 6) + ((mag << 6) >> exp) - 0x400);
|
|
|
535 }
|
|
|
536
|
|
|
537 s->sr[1] = s->sr[0];
|
|
|
538 /* FLOAT B : convert sr to 4-bit exp., 6-bit mantissa f.p. */
|
|
|
539 if (sr == 0)
|
|
|
540 {
|
|
|
541 s->sr[0] = 0x20;
|
|
|
542 }
|
|
|
543 else if (sr > 0)
|
|
|
544 {
|
|
|
545 exp = (int16_t) (top_bit(sr) + 1);
|
|
|
546 s->sr[0] = (int16_t) ((exp << 6) + ((sr << 6) >> exp));
|
|
|
547 }
|
|
|
548 else if (sr > -32768)
|
|
|
549 {
|
|
|
550 mag = (int16_t) -sr;
|
|
|
551 exp = (int16_t) (top_bit(mag) + 1);
|
|
|
552 s->sr[0] = (exp << 6) + ((mag << 6) >> exp) - 0x400;
|
|
|
553 }
|
|
|
554 else
|
|
|
555 {
|
|
|
556 s->sr[0] = (uint16_t) 0xFC20;
|
|
|
557 }
|
|
|
558
|
|
|
559 /* DELAY A */
|
|
|
560 s->pk[1] = s->pk[0];
|
|
|
561 s->pk[0] = pk0;
|
|
|
562
|
|
|
563 /* TONE */
|
|
|
564 if (tr) /* this sample has been treated as data */
|
|
|
565 s->td = FALSE; /* next one will be treated as voice */
|
|
|
566 else if (a2p < -11776) /* small sample-to-sample correlation */
|
|
|
567 s->td = TRUE; /* signal may be data */
|
|
|
568 else /* signal is voice */
|
|
|
569 s->td = FALSE;
|
|
|
570
|
|
|
571 /* Adaptation speed control. */
|
|
|
572 /* FILTA */
|
|
|
573 s->dms += ((int16_t) fi - s->dms) >> 5;
|
|
|
574 /* FILTB */
|
|
|
575 s->dml += (((int16_t) (fi << 2) - s->dml) >> 7);
|
|
|
576
|
|
|
577 if (tr)
|
|
|
578 s->ap = 256;
|
|
|
579 else if (y < 1536) /* SUBTC */
|
|
|
580 s->ap += (0x200 - s->ap) >> 4;
|
|
|
581 else if (s->td)
|
|
|
582 s->ap += (0x200 - s->ap) >> 4;
|
|
|
583 else if (abs((s->dms << 2) - s->dml) >= (s->dml >> 3))
|
|
|
584 s->ap += (0x200 - s->ap) >> 4;
|
|
|
585 else
|
|
|
586 s->ap += (-s->ap) >> 4;
|
|
|
587 }
|
|
|
588 /*- End of function --------------------------------------------------------*/
|
|
|
589
|
|
|
590 static int16_t tandem_adjust_alaw(int16_t sr, /* decoder output linear PCM sample */
|
|
|
591 int se, /* predictor estimate sample */
|
|
|
592 int y, /* quantizer step size */
|
|
|
593 int i, /* decoder input code */
|
|
|
594 int sign,
|
|
|
595 const int qtab[],
|
|
|
596 int quantizer_states)
|
|
|
597 {
|
|
|
598 uint8_t sp; /* A-law compressed 8-bit code */
|
|
|
599 int16_t dx; /* prediction error */
|
|
|
600 int id; /* quantized prediction error */
|
|
|
601 int sd; /* adjusted A-law decoded sample value */
|
|
|
602
|
|
|
603 if (sr <= -32768)
|
|
|
604 sr = -1;
|
|
|
605 sp = linear_to_alaw((sr >> 1) << 3);
|
|
|
606 /* 16-bit prediction error */
|
|
|
607 dx = (int16_t) ((alaw_to_linear(sp) >> 2) - se);
|
|
|
608 id = quantize(dx, y, qtab, quantizer_states);
|
|
|
609 if (id == i)
|
|
|
610 {
|
|
|
611 /* No adjustment of sp required */
|
|
|
612 return (int16_t) sp;
|
|
|
613 }
|
|
|
614 /* sp adjustment needed */
|
|
|
615 /* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */
|
|
|
616 /* 2's complement to biased unsigned */
|
|
|
617 if ((id ^ sign) > (i ^ sign))
|
|
|
618 {
|
|
|
619 /* sp adjusted to next lower value */
|
|
|
620 if (sp & 0x80)
|
|
|
621 sd = (sp == 0xD5) ? 0x55 : (((sp ^ 0x55) - 1) ^ 0x55);
|
|
|
622 else
|
|
|
623 sd = (sp == 0x2A) ? 0x2A : (((sp ^ 0x55) + 1) ^ 0x55);
|
|
|
624 }
|
|
|
625 else
|
|
|
626 {
|
|
|
627 /* sp adjusted to next higher value */
|
|
|
628 if (sp & 0x80)
|
|
|
629 sd = (sp == 0xAA) ? 0xAA : (((sp ^ 0x55) + 1) ^ 0x55);
|
|
|
630 else
|
|
|
631 sd = (sp == 0x55) ? 0xD5 : (((sp ^ 0x55) - 1) ^ 0x55);
|
|
|
632 }
|
|
|
633 return (int16_t) sd;
|
|
|
634 }
|
|
|
635 /*- End of function --------------------------------------------------------*/
|
|
|
636
|
|
|
637 static int16_t tandem_adjust_ulaw(int16_t sr, /* decoder output linear PCM sample */
|
|
|
638 int se, /* predictor estimate sample */
|
|
|
639 int y, /* quantizer step size */
|
|
|
640 int i, /* decoder input code */
|
|
|
641 int sign,
|
|
|
642 const int qtab[],
|
|
|
643 int quantizer_states)
|
|
|
644 {
|
|
|
645 uint8_t sp; /* u-law compressed 8-bit code */
|
|
|
646 int16_t dx; /* prediction error */
|
|
|
647 int id; /* quantized prediction error */
|
|
|
648 int sd; /* adjusted u-law decoded sample value */
|
|
|
649
|
|
|
650 if (sr <= -32768)
|
|
|
651 sr = 0;
|
|
|
652 sp = linear_to_ulaw(sr << 2);
|
|
|
653 /* 16-bit prediction error */
|
|
|
654 dx = (int16_t) ((ulaw_to_linear(sp) >> 2) - se);
|
|
|
655 id = quantize(dx, y, qtab, quantizer_states);
|
|
|
656 if (id == i)
|
|
|
657 {
|
|
|
658 /* No adjustment of sp required. */
|
|
|
659 return (int16_t) sp;
|
|
|
660 }
|
|
|
661 /* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */
|
|
|
662 /* 2's complement to biased unsigned */
|
|
|
663 if ((id ^ sign) > (i ^ sign))
|
|
|
664 {
|
|
|
665 /* sp adjusted to next lower value */
|
|
|
666 if (sp & 0x80)
|
|
|
667 sd = (sp == 0xFF) ? 0x7E : (sp + 1);
|
|
|
668 else
|
|
|
669 sd = (sp == 0x00) ? 0x00 : (sp - 1);
|
|
|
670 }
|
|
|
671 else
|
|
|
672 {
|
|
|
673 /* sp adjusted to next higher value */
|
|
|
674 if (sp & 0x80)
|
|
|
675 sd = (sp == 0x80) ? 0x80 : (sp - 1);
|
|
|
676 else
|
|
|
677 sd = (sp == 0x7F) ? 0xFE : (sp + 1);
|
|
|
678 }
|
|
|
679 return (int16_t) sd;
|
|
|
680 }
|
|
|
681 /*- End of function --------------------------------------------------------*/
|
|
|
682
|
|
|
683 /*
|
|
|
684 * Encodes a linear PCM, A-law or u-law input sample and returns its 3-bit code.
|
|
|
685 */
|
|
|
686 static uint8_t g726_16_encoder(g726_state_t *s, int16_t amp)
|
|
|
687 {
|
|
|
688 int y;
|
|
|
689 int16_t sei;
|
|
|
690 int16_t sezi;
|
|
|
691 int16_t se;
|
|
|
692 int16_t d;
|
|
|
693 int16_t sr;
|
|
|
694 int16_t dqsez;
|
|
|
695 int16_t dq;
|
|
|
696 int16_t i;
|
|
|
697
|
|
|
698 sezi = predictor_zero(s);
|
|
|
699 sei = sezi + predictor_pole(s);
|
|
|
700 se = sei >> 1;
|
|
|
701 d = amp - se;
|
|
|
702
|
|
|
703 /* Quantize prediction difference */
|
|
|
704 y = step_size(s);
|
|
|
705 i = quantize(d, y, qtab_726_16, 4);
|
|
|
706 dq = reconstruct(i & 2, g726_16_dqlntab[i], y);
|
|
|
707
|
|
|
708 /* Reconstruct the signal */
|
|
|
709 sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq);
|
|
|
710
|
|
|
711 /* Pole prediction difference */
|
|
|
712 dqsez = sr + (sezi >> 1) - se;
|
|
|
713
|
|
|
714 update(s, y, g726_16_witab[i], g726_16_fitab[i], dq, sr, dqsez);
|
|
|
715 return (uint8_t) i;
|
|
|
716 }
|
|
|
717 /*- End of function --------------------------------------------------------*/
|
|
|
718
|
|
|
719 /*
|
|
|
720 * Decodes a 2-bit CCITT G.726_16 ADPCM code and returns
|
|
|
721 * the resulting 16-bit linear PCM, A-law or u-law sample value.
|
|
|
722 */
|
|
|
723 static int16_t g726_16_decoder(g726_state_t *s, uint8_t code)
|
|
|
724 {
|
|
|
725 int16_t sezi;
|
|
|
726 int16_t sei;
|
|
|
727 int16_t se;
|
|
|
728 int16_t sr;
|
|
|
729 int16_t dq;
|
|
|
730 int16_t dqsez;
|
|
|
731 int y;
|
|
|
732
|
|
|
733 /* Mask to get proper bits */
|
|
|
734 code &= 0x03;
|
|
|
735 sezi = predictor_zero(s);
|
|
|
736 sei = sezi + predictor_pole(s);
|
|
|
737
|
|
|
738 y = step_size(s);
|
|
|
739 dq = reconstruct(code & 2, g726_16_dqlntab[code], y);
|
|
|
740
|
|
|
741 /* Reconstruct the signal */
|
|
|
742 se = sei >> 1;
|
|
|
743 sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq);
|
|
|
744
|
|
|
745 /* Pole prediction difference */
|
|
|
746 dqsez = sr + (sezi >> 1) - se;
|
|
|
747
|
|
|
748 update(s, y, g726_16_witab[code], g726_16_fitab[code], dq, sr, dqsez);
|
|
|
749
|
|
|
750 switch (s->ext_coding)
|
|
|
751 {
|
|
|
752 case G726_ENCODING_ALAW:
|
|
|
753 return tandem_adjust_alaw(sr, se, y, code, 2, qtab_726_16, 4);
|
|
|
754 case G726_ENCODING_ULAW:
|
|
|
755 return tandem_adjust_ulaw(sr, se, y, code, 2, qtab_726_16, 4);
|
|
|
756 }
|
|
|
757 return (sr << 2);
|
|
|
758 }
|
|
|
759 /*- End of function --------------------------------------------------------*/
|
|
|
760
|
|
|
761 /*
|
|
|
762 * Encodes a linear PCM, A-law or u-law input sample and returns its 3-bit code.
|
|
|
763 */
|
|
|
764 static uint8_t g726_24_encoder(g726_state_t *s, int16_t amp)
|
|
|
765 {
|
|
|
766 int16_t sei;
|
|
|
767 int16_t sezi;
|
|
|
768 int16_t se;
|
|
|
769 int16_t d;
|
|
|
770 int16_t sr;
|
|
|
771 int16_t dqsez;
|
|
|
772 int16_t dq;
|
|
|
773 int16_t i;
|
|
|
774 int y;
|
|
|
775
|
|
|
776 sezi = predictor_zero(s);
|
|
|
777 sei = sezi + predictor_pole(s);
|
|
|
778 se = sei >> 1;
|
|
|
779 d = amp - se;
|
|
|
780
|
|
|
781 /* Quantize prediction difference */
|
|
|
782 y = step_size(s);
|
|
|
783 i = quantize(d, y, qtab_726_24, 7);
|
|
|
784 dq = reconstruct(i & 4, g726_24_dqlntab[i], y);
|
|
|
785
|
|
|
786 /* Reconstruct the signal */
|
|
|
787 sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq);
|
|
|
788
|
|
|
789 /* Pole prediction difference */
|
|
|
790 dqsez = sr + (sezi >> 1) - se;
|
|
|
791
|
|
|
792 update(s, y, g726_24_witab[i], g726_24_fitab[i], dq, sr, dqsez);
|
|
|
793 return (uint8_t) i;
|
|
|
794 }
|
|
|
795 /*- End of function --------------------------------------------------------*/
|
|
|
796
|
|
|
797 /*
|
|
|
798 * Decodes a 3-bit CCITT G.726_24 ADPCM code and returns
|
|
|
799 * the resulting 16-bit linear PCM, A-law or u-law sample value.
|
|
|
800 */
|
|
|
801 static int16_t g726_24_decoder(g726_state_t *s, uint8_t code)
|
|
|
802 {
|
|
|
803 int16_t sezi;
|
|
|
804 int16_t sei;
|
|
|
805 int16_t se;
|
|
|
806 int16_t sr;
|
|
|
807 int16_t dq;
|
|
|
808 int16_t dqsez;
|
|
|
809 int y;
|
|
|
810
|
|
|
811 /* Mask to get proper bits */
|
|
|
812 code &= 0x07;
|
|
|
813 sezi = predictor_zero(s);
|
|
|
814 sei = sezi + predictor_pole(s);
|
|
|
815
|
|
|
816 y = step_size(s);
|
|
|
817 dq = reconstruct(code & 4, g726_24_dqlntab[code], y);
|
|
|
818
|
|
|
819 /* Reconstruct the signal */
|
|
|
820 se = sei >> 1;
|
|
|
821 sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq);
|
|
|
822
|
|
|
823 /* Pole prediction difference */
|
|
|
824 dqsez = sr + (sezi >> 1) - se;
|
|
|
825
|
|
|
826 update(s, y, g726_24_witab[code], g726_24_fitab[code], dq, sr, dqsez);
|
|
|
827
|
|
|
828 switch (s->ext_coding)
|
|
|
829 {
|
|
|
830 case G726_ENCODING_ALAW:
|
|
|
831 return tandem_adjust_alaw(sr, se, y, code, 4, qtab_726_24, 7);
|
|
|
832 case G726_ENCODING_ULAW:
|
|
|
833 return tandem_adjust_ulaw(sr, se, y, code, 4, qtab_726_24, 7);
|
|
|
834 }
|
|
|
835 return (sr << 2);
|
|
|
836 }
|
|
|
837 /*- End of function --------------------------------------------------------*/
|
|
|
838
|
|
|
839 /*
|
|
|
840 * Encodes a linear input sample and returns its 4-bit code.
|
|
|
841 */
|
|
|
842 static uint8_t g726_32_encoder(g726_state_t *s, int16_t amp)
|
|
|
843 {
|
|
|
844 int16_t sei;
|
|
|
845 int16_t sezi;
|
|
|
846 int16_t se;
|
|
|
847 int16_t d;
|
|
|
848 int16_t sr;
|
|
|
849 int16_t dqsez;
|
|
|
850 int16_t dq;
|
|
|
851 int16_t i;
|
|
|
852 int y;
|
|
|
853
|
|
|
854 sezi = predictor_zero(s);
|
|
|
855 sei = sezi + predictor_pole(s);
|
|
|
856 se = sei >> 1;
|
|
|
857 d = amp - se;
|
|
|
858
|
|
|
859 /* Quantize the prediction difference */
|
|
|
860 y = step_size(s);
|
|
|
861 i = quantize(d, y, qtab_726_32, 15);
|
|
|
862 dq = reconstruct(i & 8, g726_32_dqlntab[i], y);
|
|
|
863
|
|
|
864 /* Reconstruct the signal */
|
|
|
865 sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq);
|
|
|
866
|
|
|
867 /* Pole prediction difference */
|
|
|
868 dqsez = sr + (sezi >> 1) - se;
|
|
|
869
|
|
|
870 update(s, y, g726_32_witab[i], g726_32_fitab[i], dq, sr, dqsez);
|
|
|
871 return (uint8_t) i;
|
|
|
872 }
|
|
|
873 /*- End of function --------------------------------------------------------*/
|
|
|
874
|
|
|
875 /*
|
|
|
876 * Decodes a 4-bit CCITT G.726_32 ADPCM code and returns
|
|
|
877 * the resulting 16-bit linear PCM, A-law or u-law sample value.
|
|
|
878 */
|
|
|
879 static int16_t g726_32_decoder(g726_state_t *s, uint8_t code)
|
|
|
880 {
|
|
|
881 int16_t sezi;
|
|
|
882 int16_t sei;
|
|
|
883 int16_t se;
|
|
|
884 int16_t sr;
|
|
|
885 int16_t dq;
|
|
|
886 int16_t dqsez;
|
|
|
887 int y;
|
|
|
888
|
|
|
889 /* Mask to get proper bits */
|
|
|
890 code &= 0x0F;
|
|
|
891 sezi = predictor_zero(s);
|
|
|
892 sei = sezi + predictor_pole(s);
|
|
|
893
|
|
|
894 y = step_size(s);
|
|
|
895 dq = reconstruct(code & 8, g726_32_dqlntab[code], y);
|
|
|
896
|
|
|
897 /* Reconstruct the signal */
|
|
|
898 se = sei >> 1;
|
|
|
899 sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq);
|
|
|
900
|
|
|
901 /* Pole prediction difference */
|
|
|
902 dqsez = sr + (sezi >> 1) - se;
|
|
|
903
|
|
|
904 update(s, y, g726_32_witab[code], g726_32_fitab[code], dq, sr, dqsez);
|
|
|
905
|
|
|
906 switch (s->ext_coding)
|
|
|
907 {
|
|
|
908 case G726_ENCODING_ALAW:
|
|
|
909 return tandem_adjust_alaw(sr, se, y, code, 8, qtab_726_32, 15);
|
|
|
910 case G726_ENCODING_ULAW:
|
|
|
911 return tandem_adjust_ulaw(sr, se, y, code, 8, qtab_726_32, 15);
|
|
|
912 }
|
|
|
913 return (sr << 2);
|
|
|
914 }
|
|
|
915 /*- End of function --------------------------------------------------------*/
|
|
|
916
|
|
|
917 /*
|
|
|
918 * Encodes a 16-bit linear PCM, A-law or u-law input sample and retuens
|
|
|
919 * the resulting 5-bit CCITT G.726 40Kbps code.
|
|
|
920 */
|
|
|
921 static uint8_t g726_40_encoder(g726_state_t *s, int16_t amp)
|
|
|
922 {
|
|
|
923 int16_t sei;
|
|
|
924 int16_t sezi;
|
|
|
925 int16_t se;
|
|
|
926 int16_t d;
|
|
|
927 int16_t sr;
|
|
|
928 int16_t dqsez;
|
|
|
929 int16_t dq;
|
|
|
930 int16_t i;
|
|
|
931 int y;
|
|
|
932
|
|
|
933 sezi = predictor_zero(s);
|
|
|
934 sei = sezi + predictor_pole(s);
|
|
|
935 se = sei >> 1;
|
|
|
936 d = amp - se;
|
|
|
937
|
|
|
938 /* Quantize prediction difference */
|
|
|
939 y = step_size(s);
|
|
|
940 i = quantize(d, y, qtab_726_40, 31);
|
|
|
941 dq = reconstruct(i & 0x10, g726_40_dqlntab[i], y);
|
|
|
942
|
|
|
943 /* Reconstruct the signal */
|
|
|
944 sr = (dq < 0) ? (se - (dq & 0x7FFF)) : (se + dq);
|
|
|
945
|
|
|
946 /* Pole prediction difference */
|
|
|
947 dqsez = sr + (sezi >> 1) - se;
|
|
|
948
|
|
|
949 update(s, y, g726_40_witab[i], g726_40_fitab[i], dq, sr, dqsez);
|
|
|
950 return (uint8_t) i;
|
|
|
951 }
|
|
|
952 /*- End of function --------------------------------------------------------*/
|
|
|
953
|
|
|
954 /*
|
|
|
955 * Decodes a 5-bit CCITT G.726 40Kbps code and returns
|
|
|
956 * the resulting 16-bit linear PCM, A-law or u-law sample value.
|
|
|
957 */
|
|
|
958 static int16_t g726_40_decoder(g726_state_t *s, uint8_t code)
|
|
|
959 {
|
|
|
960 int16_t sezi;
|
|
|
961 int16_t sei;
|
|
|
962 int16_t se;
|
|
|
963 int16_t sr;
|
|
|
964 int16_t dq;
|
|
|
965 int16_t dqsez;
|
|
|
966 int y;
|
|
|
967
|
|
|
968 /* Mask to get proper bits */
|
|
|
969 code &= 0x1F;
|
|
|
970 sezi = predictor_zero(s);
|
|
|
971 sei = sezi + predictor_pole(s);
|
|
|
972
|
|
|
973 y = step_size(s);
|
|
|
974 dq = reconstruct(code & 0x10, g726_40_dqlntab[code], y);
|
|
|
975
|
|
|
976 /* Reconstruct the signal */
|
|
|
977 se = sei >> 1;
|
|
|
978 sr = (dq < 0) ? (se - (dq & 0x7FFF)) : (se + dq);
|
|
|
979
|
|
|
980 /* Pole prediction difference */
|
|
|
981 dqsez = sr + (sezi >> 1) - se;
|
|
|
982
|
|
|
983 update(s, y, g726_40_witab[code], g726_40_fitab[code], dq, sr, dqsez);
|
|
|
984
|
|
|
985 switch (s->ext_coding)
|
|
|
986 {
|
|
|
987 case G726_ENCODING_ALAW:
|
|
|
988 return tandem_adjust_alaw(sr, se, y, code, 0x10, qtab_726_40, 31);
|
|
|
989 case G726_ENCODING_ULAW:
|
|
|
990 return tandem_adjust_ulaw(sr, se, y, code, 0x10, qtab_726_40, 31);
|
|
|
991 }
|
|
|
992 return (sr << 2);
|
|
|
993 }
|
|
|
994 /*- End of function --------------------------------------------------------*/
|
|
|
995
|
|
|
996 g726_state_t *g726_init(g726_state_t *s, int bit_rate, int ext_coding, int packing)
|
|
|
997 {
|
|
|
998 int i;
|
|
|
999
|
|
|
1000 if (bit_rate != 16000 && bit_rate != 24000 && bit_rate != 32000 && bit_rate != 40000)
|
|
|
1001 return NULL;
|
|
|
1002 if (s == NULL)
|
|
|
1003 {
|
|
|
1004 if ((s = (g726_state_t *) malloc(sizeof(*s))) == NULL)
|
|
|
1005 return NULL;
|
|
|
1006 }
|
|
|
1007 s->yl = 34816;
|
|
|
1008 s->yu = 544;
|
|
|
1009 s->dms = 0;
|
|
|
1010 s->dml = 0;
|
|
|
1011 s->ap = 0;
|
|
|
1012 s->rate = bit_rate;
|
|
|
1013 s->ext_coding = ext_coding;
|
|
|
1014 s->packing = packing;
|
|
|
1015 for (i = 0; i < 2; i++)
|
|
|
1016 {
|
|
|
1017 s->a[i] = 0;
|
|
|
1018 s->pk[i] = 0;
|
|
|
1019 s->sr[i] = 32;
|
|
|
1020 }
|
|
|
1021 for (i = 0; i < 6; i++)
|
|
|
1022 {
|
|
|
1023 s->b[i] = 0;
|
|
|
1024 s->dq[i] = 32;
|
|
|
1025 }
|
|
|
1026 s->td = FALSE;
|
|
|
1027 switch (bit_rate)
|
|
|
1028 {
|
|
|
1029 case 16000:
|
|
|
1030 s->enc_func = g726_16_encoder;
|
|
|
1031 s->dec_func = g726_16_decoder;
|
|
|
1032 s->bits_per_sample = 2;
|
|
|
1033 break;
|
|
|
1034 case 24000:
|
|
|
1035 s->enc_func = g726_24_encoder;
|
|
|
1036 s->dec_func = g726_24_decoder;
|
|
|
1037 s->bits_per_sample = 3;
|
|
|
1038 break;
|
|
|
1039 case 32000:
|
|
|
1040 default:
|
|
|
1041 s->enc_func = g726_32_encoder;
|
|
|
1042 s->dec_func = g726_32_decoder;
|
|
|
1043 s->bits_per_sample = 4;
|
|
|
1044 break;
|
|
|
1045 case 40000:
|
|
|
1046 s->enc_func = g726_40_encoder;
|
|
|
1047 s->dec_func = g726_40_decoder;
|
|
|
1048 s->bits_per_sample = 5;
|
|
|
1049 break;
|
|
|
1050 }
|
|
|
1051 bitstream_init(&s->bs);
|
|
|
1052 return s;
|
|
|
1053 }
|
|
|
1054 /*- End of function --------------------------------------------------------*/
|
|
|
1055
|
|
|
1056 int g726_release(g726_state_t *s)
|
|
|
1057 {
|
|
|
1058 free(s);
|
|
|
1059 return 0;
|
|
|
1060 }
|
|
|
1061 /*- End of function --------------------------------------------------------*/
|
|
|
1062
|
|
|
1063 int g726_decode(g726_state_t *s,
|
|
|
1064 int16_t amp[],
|
|
|
1065 const uint8_t g726_data[],
|
|
|
1066 int g726_bytes)
|
|
|
1067 {
|
|
|
1068 int i;
|
|
|
1069 int samples;
|
|
|
1070 uint8_t code;
|
|
|
1071 int sl;
|
|
|
1072
|
|
|
1073 for (samples = i = 0; ; )
|
|
|
1074 {
|
|
|
1075 if (s->packing != G726_PACKING_NONE)
|
|
|
1076 {
|
|
|
1077 /* Unpack the code bits */
|
|
|
1078 if (s->packing != G726_PACKING_LEFT)
|
|
|
1079 {
|
|
|
1080 if (s->bs.residue < s->bits_per_sample)
|
|
|
1081 {
|
|
|
1082 if (i >= g726_bytes)
|
|
|
1083 break;
|
|
|
1084 s->bs.bitstream |= (g726_data[i++] << s->bs.residue);
|
|
|
1085 s->bs.residue += 8;
|
|
|
1086 }
|
|
|
1087 code = (uint8_t) (s->bs.bitstream & ((1 << s->bits_per_sample) - 1));
|
|
|
1088 s->bs.bitstream >>= s->bits_per_sample;
|
|
|
1089 }
|
|
|
1090 else
|
|
|
1091 {
|
|
|
1092 if (s->bs.residue < s->bits_per_sample)
|
|
|
1093 {
|
|
|
1094 if (i >= g726_bytes)
|
|
|
1095 break;
|
|
|
1096 s->bs.bitstream = (s->bs.bitstream << 8) | g726_data[i++];
|
|
|
1097 s->bs.residue += 8;
|
|
|
1098 }
|
|
|
1099 code = (uint8_t) ((s->bs.bitstream >> (s->bs.residue - s->bits_per_sample)) & ((1 << s->bits_per_sample) - 1));
|
|
|
1100 }
|
|
|
1101 s->bs.residue -= s->bits_per_sample;
|
|
|
1102 }
|
|
|
1103 else
|
|
|
1104 {
|
|
|
1105 if (i >= g726_bytes)
|
|
|
1106 break;
|
|
|
1107 code = g726_data[i++];
|
|
|
1108 }
|
|
|
1109 sl = s->dec_func(s, code);
|
|
|
1110 if (s->ext_coding != G726_ENCODING_LINEAR)
|
|
|
1111 ((uint8_t *) amp)[samples++] = (uint8_t) sl;
|
|
|
1112 else
|
|
|
1113 amp[samples++] = (int16_t) sl;
|
|
|
1114 }
|
|
|
1115 return samples;
|
|
|
1116 }
|
|
|
1117 /*- End of function --------------------------------------------------------*/
|
|
|
1118
|
|
|
1119 int g726_encode(g726_state_t *s,
|
|
|
1120 uint8_t g726_data[],
|
|
|
1121 const int16_t amp[],
|
|
|
1122 int len)
|
|
|
1123 {
|
|
|
1124 int i;
|
|
|
1125 int g726_bytes;
|
|
|
1126 int16_t sl;
|
|
|
1127 uint8_t code;
|
|
|
1128
|
|
|
1129 for (g726_bytes = i = 0; i < len; i++)
|
|
|
1130 {
|
|
|
1131 /* Linearize the input sample to 14-bit PCM */
|
|
|
1132 switch (s->ext_coding)
|
|
|
1133 {
|
|
|
1134 case G726_ENCODING_ALAW:
|
|
|
1135 sl = alaw_to_linear(((const uint8_t *) amp)[i]) >> 2;
|
|
|
1136 break;
|
|
|
1137 case G726_ENCODING_ULAW:
|
|
|
1138 sl = ulaw_to_linear(((const uint8_t *) amp)[i]) >> 2;
|
|
|
1139 break;
|
|
|
1140 default:
|
|
|
1141 sl = amp[i] >> 2;
|
|
|
1142 break;
|
|
|
1143 }
|
|
|
1144 code = s->enc_func(s, sl);
|
|
|
1145 if (s->packing != G726_PACKING_NONE)
|
|
|
1146 {
|
|
|
1147 /* Pack the code bits */
|
|
|
1148 if (s->packing != G726_PACKING_LEFT)
|
|
|
1149 {
|
|
|
1150 s->bs.bitstream |= (code << s->bs.residue);
|
|
|
1151 s->bs.residue += s->bits_per_sample;
|
|
|
1152 if (s->bs.residue >= 8)
|
|
|
1153 {
|
|
|
1154 g726_data[g726_bytes++] = (uint8_t) (s->bs.bitstream & 0xFF);
|
|
|
1155 s->bs.bitstream >>= 8;
|
|
|
1156 s->bs.residue -= 8;
|
|
|
1157 }
|
|
|
1158 }
|
|
|
1159 else
|
|
|
1160 {
|
|
|
1161 s->bs.bitstream = (s->bs.bitstream << s->bits_per_sample) | code;
|
|
|
1162 s->bs.residue += s->bits_per_sample;
|
|
|
1163 if (s->bs.residue >= 8)
|
|
|
1164 {
|
|
|
1165 g726_data[g726_bytes++] = (uint8_t) ((s->bs.bitstream >> (s->bs.residue - 8)) & 0xFF);
|
|
|
1166 s->bs.residue -= 8;
|
|
|
1167 }
|
|
|
1168 }
|
|
|
1169 }
|
|
|
1170 else
|
|
|
1171 {
|
|
|
1172 g726_data[g726_bytes++] = (uint8_t) code;
|
|
|
1173 }
|
|
|
1174 }
|
|
|
1175 return g726_bytes;
|
|
|
1176 }
|
|
|
1177 /*- End of function --------------------------------------------------------*/
|
|
|
1178 /*- End of file ------------------------------------------------------------*/
|
