1 /* 2 * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 /* 12 * arith_routines.h 13 * 14 * This file contains functions for arithmatically encoding and 15 * decoding DFT coefficients. 16 * 17 */ 18 19 20 #include "arith_routines.h" 21 22 23 24 static const WebRtc_Word32 kHistEdgesQ15[51] = { 25 -327680, -314573, -301466, -288359, -275252, -262144, -249037, -235930, -222823, -209716, 26 -196608, -183501, -170394, -157287, -144180, -131072, -117965, -104858, -91751, -78644, 27 -65536, -52429, -39322, -26215, -13108, 0, 13107, 26214, 39321, 52428, 28 65536, 78643, 91750, 104857, 117964, 131072, 144179, 157286, 170393, 183500, 29 196608, 209715, 222822, 235929, 249036, 262144, 275251, 288358, 301465, 314572, 30 327680}; 31 32 33 static const int kCdfSlopeQ0[51] = { /* Q0 */ 34 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 35 5, 5, 13, 23, 47, 87, 154, 315, 700, 1088, 36 2471, 6064, 14221, 21463, 36634, 36924, 19750, 13270, 5806, 2312, 37 1095, 660, 316, 145, 86, 41, 32, 5, 5, 5, 38 5, 5, 5, 5, 5, 5, 5, 5, 5, 2, 0}; 39 40 41 static const int kCdfQ16[51] = { /* Q16 */ 42 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 43 20, 22, 24, 29, 38, 57, 92, 153, 279, 559, 44 994, 1983, 4408, 10097, 18682, 33336, 48105, 56005, 61313, 63636, 45 64560, 64998, 65262, 65389, 65447, 65481, 65497, 65510, 65512, 65514, 46 65516, 65518, 65520, 65522, 65524, 65526, 65528, 65530, 65532, 65534, 47 65535}; 48 49 50 51 /* function to be converted to fixed point */ 52 static __inline WebRtc_UWord32 piecewise(WebRtc_Word32 xinQ15) { 53 54 WebRtc_Word32 ind, qtmp1, qtmp2, qtmp3; 55 WebRtc_UWord32 tmpUW32; 56 57 58 qtmp2 = xinQ15; 59 60 if (qtmp2 < kHistEdgesQ15[0]) { 61 qtmp2 = kHistEdgesQ15[0]; 62 } 63 if (qtmp2 > kHistEdgesQ15[50]) { 64 qtmp2 = kHistEdgesQ15[50]; 65 } 66 67 qtmp1 = qtmp2 - kHistEdgesQ15[0]; /* Q15 - Q15 = Q15 */ 68 ind = (qtmp1 * 5) >> 16; /* 2^16 / 5 = 0.4 in Q15 */ 69 /* Q15 -> Q0 */ 70 qtmp1 = qtmp2 - kHistEdgesQ15[ind]; /* Q15 - Q15 = Q15 */ 71 qtmp2 = kCdfSlopeQ0[ind] * qtmp1; /* Q0 * Q15 = Q15 */ 72 qtmp3 = qtmp2>>15; /* Q15 -> Q0 */ 73 74 tmpUW32 = kCdfQ16[ind] + qtmp3; /* Q0 + Q0 = Q0 */ 75 return tmpUW32; 76 } 77 78 79 80 int WebRtcIsac_EncLogisticMulti2( 81 Bitstr *streamdata, /* in-/output struct containing bitstream */ 82 WebRtc_Word16 *dataQ7, /* input: data vector */ 83 const WebRtc_UWord16 *envQ8, /* input: side info vector defining the width of the pdf */ 84 const int N, /* input: data vector length / 2 */ 85 const WebRtc_Word16 isSWB12kHz) 86 { 87 WebRtc_UWord32 W_lower, W_upper; 88 WebRtc_UWord32 W_upper_LSB, W_upper_MSB; 89 WebRtc_UWord8 *stream_ptr; 90 WebRtc_UWord8 *maxStreamPtr; 91 WebRtc_UWord8 *stream_ptr_carry; 92 WebRtc_UWord32 cdf_lo, cdf_hi; 93 int k; 94 95 /* point to beginning of stream buffer */ 96 stream_ptr = streamdata->stream + streamdata->stream_index; 97 W_upper = streamdata->W_upper; 98 99 maxStreamPtr = streamdata->stream + STREAM_SIZE_MAX_60 - 1; 100 for (k = 0; k < N; k++) 101 { 102 /* compute cdf_lower and cdf_upper by evaluating the piecewise linear cdf */ 103 cdf_lo = piecewise((*dataQ7 - 64) * *envQ8); 104 cdf_hi = piecewise((*dataQ7 + 64) * *envQ8); 105 106 /* test and clip if probability gets too small */ 107 while (cdf_lo+1 >= cdf_hi) { 108 /* clip */ 109 if (*dataQ7 > 0) { 110 *dataQ7 -= 128; 111 cdf_hi = cdf_lo; 112 cdf_lo = piecewise((*dataQ7 - 64) * *envQ8); 113 } else { 114 *dataQ7 += 128; 115 cdf_lo = cdf_hi; 116 cdf_hi = piecewise((*dataQ7 + 64) * *envQ8); 117 } 118 } 119 120 dataQ7++; 121 // increment only once per 4 iterations for SWB-16kHz or WB 122 // increment only once per 2 iterations for SWB-12kHz 123 envQ8 += (isSWB12kHz)? (k & 1):((k & 1) & (k >> 1)); 124 125 126 /* update interval */ 127 W_upper_LSB = W_upper & 0x0000FFFF; 128 W_upper_MSB = W_upper >> 16; 129 W_lower = W_upper_MSB * cdf_lo; 130 W_lower += (W_upper_LSB * cdf_lo) >> 16; 131 W_upper = W_upper_MSB * cdf_hi; 132 W_upper += (W_upper_LSB * cdf_hi) >> 16; 133 134 /* shift interval such that it begins at zero */ 135 W_upper -= ++W_lower; 136 137 /* add integer to bitstream */ 138 streamdata->streamval += W_lower; 139 140 /* handle carry */ 141 if (streamdata->streamval < W_lower) 142 { 143 /* propagate carry */ 144 stream_ptr_carry = stream_ptr; 145 while (!(++(*--stream_ptr_carry))); 146 } 147 148 /* renormalize interval, store most significant byte of streamval and update streamval */ 149 while ( !(W_upper & 0xFF000000) ) /* W_upper < 2^24 */ 150 { 151 W_upper <<= 8; 152 *stream_ptr++ = (WebRtc_UWord8) (streamdata->streamval >> 24); 153 154 if(stream_ptr > maxStreamPtr) 155 { 156 return -ISAC_DISALLOWED_BITSTREAM_LENGTH; 157 } 158 streamdata->streamval <<= 8; 159 } 160 } 161 162 /* calculate new stream_index */ 163 streamdata->stream_index = (int)(stream_ptr - streamdata->stream); 164 streamdata->W_upper = W_upper; 165 166 return 0; 167 } 168 169 170 171 int WebRtcIsac_DecLogisticMulti2( 172 WebRtc_Word16 *dataQ7, /* output: data vector */ 173 Bitstr *streamdata, /* in-/output struct containing bitstream */ 174 const WebRtc_UWord16 *envQ8, /* input: side info vector defining the width of the pdf */ 175 const WebRtc_Word16 *ditherQ7,/* input: dither vector */ 176 const int N, /* input: data vector length */ 177 const WebRtc_Word16 isSWB12kHz) 178 { 179 WebRtc_UWord32 W_lower, W_upper; 180 WebRtc_UWord32 W_tmp; 181 WebRtc_UWord32 W_upper_LSB, W_upper_MSB; 182 WebRtc_UWord32 streamval; 183 const WebRtc_UWord8 *stream_ptr; 184 WebRtc_UWord32 cdf_tmp; 185 WebRtc_Word16 candQ7; 186 int k; 187 188 stream_ptr = streamdata->stream + streamdata->stream_index; 189 W_upper = streamdata->W_upper; 190 if (streamdata->stream_index == 0) /* first time decoder is called for this stream */ 191 { 192 /* read first word from bytestream */ 193 streamval = *stream_ptr << 24; 194 streamval |= *++stream_ptr << 16; 195 streamval |= *++stream_ptr << 8; 196 streamval |= *++stream_ptr; 197 } else { 198 streamval = streamdata->streamval; 199 } 200 201 202 for (k = 0; k < N; k++) 203 { 204 /* find the integer *data for which streamval lies in [W_lower+1, W_upper] */ 205 W_upper_LSB = W_upper & 0x0000FFFF; 206 W_upper_MSB = W_upper >> 16; 207 208 /* find first candidate by inverting the logistic cdf */ 209 candQ7 = - *ditherQ7 + 64; 210 cdf_tmp = piecewise(candQ7 * *envQ8); 211 212 W_tmp = W_upper_MSB * cdf_tmp; 213 W_tmp += (W_upper_LSB * cdf_tmp) >> 16; 214 if (streamval > W_tmp) 215 { 216 W_lower = W_tmp; 217 candQ7 += 128; 218 cdf_tmp = piecewise(candQ7 * *envQ8); 219 220 W_tmp = W_upper_MSB * cdf_tmp; 221 W_tmp += (W_upper_LSB * cdf_tmp) >> 16; 222 while (streamval > W_tmp) 223 { 224 W_lower = W_tmp; 225 candQ7 += 128; 226 cdf_tmp = piecewise(candQ7 * *envQ8); 227 228 W_tmp = W_upper_MSB * cdf_tmp; 229 W_tmp += (W_upper_LSB * cdf_tmp) >> 16; 230 231 /* error check */ 232 if (W_lower == W_tmp) return -1; 233 } 234 W_upper = W_tmp; 235 236 /* another sample decoded */ 237 *dataQ7 = candQ7 - 64; 238 } 239 else 240 { 241 W_upper = W_tmp; 242 candQ7 -= 128; 243 cdf_tmp = piecewise(candQ7 * *envQ8); 244 245 W_tmp = W_upper_MSB * cdf_tmp; 246 W_tmp += (W_upper_LSB * cdf_tmp) >> 16; 247 while ( !(streamval > W_tmp) ) 248 { 249 W_upper = W_tmp; 250 candQ7 -= 128; 251 cdf_tmp = piecewise(candQ7 * *envQ8); 252 253 W_tmp = W_upper_MSB * cdf_tmp; 254 W_tmp += (W_upper_LSB * cdf_tmp) >> 16; 255 256 /* error check */ 257 if (W_upper == W_tmp) return -1; 258 } 259 W_lower = W_tmp; 260 261 /* another sample decoded */ 262 *dataQ7 = candQ7 + 64; 263 } 264 ditherQ7++; 265 dataQ7++; 266 // increment only once per 4 iterations for SWB-16kHz or WB 267 // increment only once per 2 iterations for SWB-12kHz 268 envQ8 += (isSWB12kHz)? (k & 1):((k & 1) & (k >> 1)); 269 270 /* shift interval to start at zero */ 271 W_upper -= ++W_lower; 272 273 /* add integer to bitstream */ 274 streamval -= W_lower; 275 276 /* renormalize interval and update streamval */ 277 while ( !(W_upper & 0xFF000000) ) /* W_upper < 2^24 */ 278 { 279 /* read next byte from stream */ 280 streamval = (streamval << 8) | *++stream_ptr; 281 W_upper <<= 8; 282 } 283 } 284 285 streamdata->stream_index = (int)(stream_ptr - streamdata->stream); 286 streamdata->W_upper = W_upper; 287 streamdata->streamval = streamval; 288 289 /* find number of bytes in original stream (determined by current interval width) */ 290 if ( W_upper > 0x01FFFFFF ) 291 return streamdata->stream_index - 2; 292 else 293 return streamdata->stream_index - 1; 294 } 295
