1/* 2 * This source code is a product of Sun Microsystems, Inc. and is provided 3 * for unrestricted use. Users may copy or modify this source code without 4 * charge. 5 * 6 * SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING 7 * THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR 8 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE. 9 * 10 * Sun source code is provided with no support and without any obligation on 11 * the part of Sun Microsystems, Inc. to assist in its use, correction, 12 * modification or enhancement. 13 * 14 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE 15 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE 16 * OR ANY PART THEREOF. 17 * 18 * In no event will Sun Microsystems, Inc. be liable for any lost revenue 19 * or profits or other special, indirect and consequential damages, even if 20 * Sun has been advised of the possibility of such damages. 21 * 22 * Sun Microsystems, Inc. 23 * 2550 Garcia Avenue 24 * Mountain View, California 94043 25 */ 26 27/* 28 * g723_40.c 29 * 30 * Description: 31 * 32 * g723_40_encoder(), g723_40_decoder() 33 * 34 * These routines comprise an implementation of the CCITT G.723 40Kbps 35 * ADPCM coding algorithm. Essentially, this implementation is identical to 36 * the bit level description except for a few deviations which 37 * take advantage of workstation attributes, such as hardware 2's 38 * complement arithmetic. 39 * 40 * The deviation from the bit level specification (lookup tables), 41 * preserves the bit level performance specifications. 42 * 43 * As outlined in the G.723 Recommendation, the algorithm is broken 44 * down into modules. Each section of code below is preceded by 45 * the name of the module which it is implementing. 46 * 47 */ 48#include "wx/wxprec.h" 49#include "wx/mmedia/internal/g72x.h" 50 51/* 52 * Maps G.723_40 code word to ructeconstructed scale factor normalized log 53 * magnitude values. 54 */ 55static short _dqlntab[32] = {-2048, -66, 28, 104, 169, 224, 274, 318, 56 358, 395, 429, 459, 488, 514, 539, 566, 57 566, 539, 514, 488, 459, 429, 395, 358, 58 318, 274, 224, 169, 104, 28, -66, -2048}; 59 60/* Maps G.723_40 code word to log of scale factor multiplier. */ 61static short _witab[32] = {448, 448, 768, 1248, 1280, 1312, 1856, 3200, 62 4512, 5728, 7008, 8960, 11456, 14080, 16928, 22272, 63 22272, 16928, 14080, 11456, 8960, 7008, 5728, 4512, 64 3200, 1856, 1312, 1280, 1248, 768, 448, 448}; 65 66/* 67 * Maps G.723_40 code words to a set of values whose long and short 68 * term averages are computed and then compared to give an indication 69 * how stationary (steady state) the signal is. 70 */ 71static short _fitab[32] = {0, 0, 0, 0, 0, 0x200, 0x200, 0x200, 72 0x200, 0x200, 0x400, 0x600, 0x800, 0xA00, 0xC00, 0xC00, 73 0xC00, 0xC00, 0xA00, 0x800, 0x600, 0x400, 0x200, 0x200, 74 0x200, 0x200, 0x200, 0, 0, 0, 0, 0}; 75 76static short qtab_723_40[15] = {-122, -16, 68, 139, 198, 250, 298, 339, 77 378, 413, 445, 475, 502, 528, 553}; 78 79/* 80 * g723_40_encoder() 81 * 82 * Encodes a 16-bit linear PCM, A-law or u-law input sample and retuens 83 * the resulting 5-bit CCITT G.723 40Kbps code. 84 * Returns -1 if the input coding value is invalid. 85 */ 86int 87g723_40_encoder( 88 int sl, 89 int in_coding, 90 struct g72x_state *state_ptr) 91{ 92 short sei, sezi, se, sez; /* ACCUM */ 93 short d; /* SUBTA */ 94 short y; /* MIX */ 95 short sr; /* ADDB */ 96 short dqsez; /* ADDC */ 97 short dq, i; 98 99 switch (in_coding) { /* linearize input sample to 14-bit PCM */ 100 case AUDIO_ENCODING_ALAW: 101 sl = alaw2linear(sl) >> 2; 102 break; 103 case AUDIO_ENCODING_ULAW: 104 sl = ulaw2linear(sl) >> 2; 105 break; 106 case AUDIO_ENCODING_LINEAR: 107 sl = ((short) sl) >> 2; /* sl of 14-bit dynamic range */ 108 break; 109 default: 110 return (-1); 111 } 112 113 sezi = predictor_zero(state_ptr); 114 sez = sezi >> 1; 115 sei = sezi + predictor_pole(state_ptr); 116 se = sei >> 1; /* se = estimated signal */ 117 118 d = sl - se; /* d = estimation difference */ 119 120 /* quantize prediction difference */ 121 y = step_size(state_ptr); /* adaptive quantizer step size */ 122 i = quantize(d, y, qtab_723_40, 15); /* i = ADPCM code */ 123 124 dq = reconstruct(i & 0x10, _dqlntab[i], y); /* quantized diff */ 125 126 sr = (dq < 0) ? se - (dq & 0x7FFF) : se + dq; /* reconstructed signal */ 127 128 dqsez = sr + sez - se; /* dqsez = pole prediction diff. */ 129 130 update(5, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr); 131 132 return (i); 133} 134 135/* 136 * g723_40_decoder() 137 * 138 * Decodes a 5-bit CCITT G.723 40Kbps code and returns 139 * the resulting 16-bit linear PCM, A-law or u-law sample value. 140 * -1 is returned if the output coding is unknown. 141 */ 142int 143g723_40_decoder( 144 int i, 145 int out_coding, 146 struct g72x_state *state_ptr) 147{ 148 short sezi, sei, sez, se; /* ACCUM */ 149 short y; /* MIX */ 150 short sr; /* ADDB */ 151 short dq; 152 short dqsez; 153 154 i &= 0x1f; /* mask to get proper bits */ 155 sezi = predictor_zero(state_ptr); 156 sez = sezi >> 1; 157 sei = sezi + predictor_pole(state_ptr); 158 se = sei >> 1; /* se = estimated signal */ 159 160 y = step_size(state_ptr); /* adaptive quantizer step size */ 161 dq = reconstruct(i & 0x10, _dqlntab[i], y); /* estimation diff. */ 162 163 sr = (dq < 0) ? (se - (dq & 0x7FFF)) : (se + dq); /* reconst. signal */ 164 165 dqsez = sr - se + sez; /* pole prediction diff. */ 166 167 update(5, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr); 168 169 switch (out_coding) { 170 case AUDIO_ENCODING_ALAW: 171 return (tandem_adjust_alaw(sr, se, y, i, 0x10, qtab_723_40)); 172 case AUDIO_ENCODING_ULAW: 173 return (tandem_adjust_ulaw(sr, se, y, i, 0x10, qtab_723_40)); 174 case AUDIO_ENCODING_LINEAR: 175 return (sr << 2); /* sr was of 14-bit dynamic range */ 176 default: 177 return (-1); 178 } 179} 180