1 /* ------------------------------------------------------------------ 2 * Copyright (C) 1998-2009 PacketVideo 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either 13 * express or implied. 14 * See the License for the specific language governing permissions 15 * and limitations under the License. 16 * ------------------------------------------------------------------- 17 */ 18 /**************************************************************************************** 19 Portions of this file are derived from the following 3GPP standard: 20 21 3GPP TS 26.073 22 ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec 23 Available from http://www.3gpp.org 24 25 (C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC) 26 Permission to distribute, modify and use this file under the standard license 27 terms listed above has been obtained from the copyright holder. 28 ****************************************************************************************/ 29 /* 30 ------------------------------------------------------------------------------ 31 32 33 34 Pathname: ./audio/gsm-amr/c/src/enc_lag3.c 35 Functions: 36 37 Date: 01/28/2002 38 39 ------------------------------------------------------------------------------ 40 REVISION HISTORY 41 42 Description: Replaced "int" and/or "char" with OSCL defined types. 43 44 Description: 45 46 ------------------------------------------------------------------------------ 47 */ 48 49 /*---------------------------------------------------------------------------- 50 ; INCLUDES 51 ----------------------------------------------------------------------------*/ 52 #include "enc_lag3.h" 53 #include "typedef.h" 54 #include "basic_op.h" 55 #include "cnst.h" 56 57 /*---------------------------------------------------------------------------- 58 ; MACROS 59 ; Define module specific macros here 60 ----------------------------------------------------------------------------*/ 61 62 /*---------------------------------------------------------------------------- 63 ; DEFINES 64 ; Include all pre-processor statements here. Include conditional 65 ; compile variables also. 66 ----------------------------------------------------------------------------*/ 67 68 69 /*---------------------------------------------------------------------------- 70 ; LOCAL FUNCTION DEFINITIONS 71 ; Function Prototype declaration 72 ----------------------------------------------------------------------------*/ 73 74 75 /*---------------------------------------------------------------------------- 76 ; LOCAL VARIABLE DEFINITIONS 77 ; Variable declaration - defined here and used outside this module 78 ----------------------------------------------------------------------------*/ 79 80 /* 81 ------------------------------------------------------------------------------ 82 FUNCTION NAME: enc_lag3 83 ------------------------------------------------------------------------------ 84 INPUT AND OUTPUT DEFINITIONS 85 86 Inputs: 87 T0 = Pitch delay of type Word16 88 T0_frac = Fractional pitch delay of type Word16 89 T0_prev = Integer pitch delay of last subframe of type Word16 90 T0_min = minimum of search range of type Word16 91 T0_max = maximum of search range of type Word16 92 delta_flag = Flag for 1st (or 3rd) subframe of type Word16 93 flag4 = Flag for encoding with 4 bits of type Word16 94 pOverflow = pointer indicating overflow of type Flag 95 96 Outputs: 97 pOverflow = 1 if there is an overflow else it is zero. 98 99 Returns: 100 None 101 102 Global Variables Used: 103 None 104 105 Local Variables Needed: 106 None 107 108 ------------------------------------------------------------------------------ 109 FUNCTION DESCRIPTION 110 111 This function implements the encoding of fractional pitch lag with 112 1/3 resolution. 113 114 * FUNCTION: Enc_lag3 115 * 116 * PURPOSE: Encoding of fractional pitch lag with 1/3 resolution. 117 * 118 * DESCRIPTION: 119 * First and third subframes: 120 * -------------------------- 121 * The pitch range is divided as follows: 122 * 19 1/3 to 84 2/3 resolution 1/3 123 * 85 to 143 resolution 1 124 * 125 * The period is encoded with 8 bits. 126 * For the range with fractions: 127 * index = (T-19)*3 + frac - 1; 128 * where T=[19..85] and frac=[-1,0,1] 129 * and for the integer only range 130 * index = (T - 85) + 197; where T=[86..143] 131 * 132 * Second and fourth subframes: 133 * ---------------------------- 134 * For the 2nd and 4th subframes a resolution of 1/3 is always used, 135 * and the search range is relative to the lag in previous subframe. 136 * If t0 is the lag in the previous subframe then 137 * t_min=t0-5 and t_max=t0+4 and the range is given by 138 * t_min - 2/3 to t_max + 2/3 139 * 140 * The period in the 2nd (and 4th) subframe is encoded with 5 bits: 141 * index = (T-(t_min-1))*3 + frac - 1; 142 * where T=[t_min-1..t_max+1] 143 144 ------------------------------------------------------------------------------ 145 REQUIREMENTS 146 147 None 148 149 ------------------------------------------------------------------------------ 150 REFERENCES 151 152 enc_lag3.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 153 154 ------------------------------------------------------------------------------ 155 PSEUDO-CODE 156 157 Word16 index, i, tmp_ind, uplag; 158 Word16 tmp_lag; 159 160 if (delta_flag == 0) 161 { // if 1st or 3rd subframe 162 163 // encode pitch delay (with fraction) 164 165 if (sub (T0, 85) <= 0) 166 { 167 // index = T0*3 - 58 + T0_frac 168 i = add (add (T0, T0), T0); 169 index = add (sub (i, 58), T0_frac); 170 } 171 else 172 { 173 index = add (T0, 112); 174 } 175 } 176 else 177 { // if second or fourth subframe 178 if (flag4 == 0) { 179 180 // 'normal' encoding: either with 5 or 6 bit resolution 181 182 // index = 3*(T0 - T0_min) + 2 + T0_frac 183 i = sub (T0, T0_min); 184 i = add (add (i, i), i); 185 index = add (add (i, 2), T0_frac); 186 } 187 else { 188 189 // encoding with 4 bit resolution 190 191 tmp_lag = T0_prev; 192 193 if ( sub( sub(tmp_lag, T0_min), 5) > 0) 194 tmp_lag = add (T0_min, 5); 195 if ( sub( sub(T0_max, tmp_lag), 4) > 0) 196 tmp_lag = sub (T0_max, 4); 197 198 uplag = add (add (add (T0, T0), T0), T0_frac); 199 200 i = sub (tmp_lag, 2); 201 tmp_ind = add (add (i, i), i); 202 203 if (sub (tmp_ind, uplag) >= 0) { 204 index = add (sub (T0, tmp_lag), 5); 205 } 206 else { 207 208 i = add (tmp_lag, 1); 209 i = add (add (i, i), i); 210 211 if (sub (i, uplag) > 0) { 212 213 index = add ( sub (uplag, tmp_ind), 3); 214 } 215 else { 216 217 index = add (sub (T0, tmp_lag), 11); 218 } 219 } 220 221 } // end if (encoding with 4 bit resolution) 222 } // end if (second of fourth subframe) 223 224 return index; 225 } 226 227 ------------------------------------------------------------------------------ 228 RESOURCES USED [optional] 229 230 When the code is written for a specific target processor the 231 the resources used should be documented below. 232 233 HEAP MEMORY USED: x bytes 234 235 STACK MEMORY USED: x bytes 236 237 CLOCK CYCLES: (cycle count equation for this function) + (variable 238 used to represent cycle count for each subroutine 239 called) 240 where: (cycle count variable) = cycle count for [subroutine 241 name] 242 243 ------------------------------------------------------------------------------ 244 CAUTION [optional] 245 [State any special notes, constraints or cautions for users of this function] 246 247 ------------------------------------------------------------------------------ 248 */ 249 250 251 Word16 Enc_lag3( /* o : Return index of encoding */ 252 Word16 T0, /* i : Pitch delay */ 253 Word16 T0_frac, /* i : Fractional pitch delay */ 254 Word16 T0_prev, /* i : Integer pitch delay of last subframe */ 255 Word16 T0_min, /* i : minimum of search range */ 256 Word16 T0_max, /* i : maximum of search range */ 257 Word16 delta_flag, /* i : Flag for 1st (or 3rd) subframe */ 258 Word16 flag4, /* i : Flag for encoding with 4 bits */ 259 Flag *pOverflow 260 ) 261 { 262 Word16 index, i, tmp_ind, uplag; 263 Word16 tmp_lag; 264 Word16 temp1; 265 Word16 temp2; 266 267 268 269 if (delta_flag == 0) 270 { /* if 1st or 3rd subframe */ 271 272 /* encode pitch delay (with fraction) */ 273 temp1 = sub(T0, 85, pOverflow); 274 if (temp1 <= 0) 275 { 276 /* index = T0*3 - 58 + T0_frac */ 277 temp2 = add(T0, T0, pOverflow); 278 i = add(temp2, T0, pOverflow); 279 temp2 = sub(i, 58, pOverflow); 280 index = add(temp2, T0_frac, pOverflow); 281 } 282 else 283 { 284 index = add(T0, 112, pOverflow); 285 } 286 } 287 else 288 { /* if second or fourth subframe */ 289 if (flag4 == 0) 290 { 291 292 /* 'normal' encoding: either with 5 or 6 bit resolution */ 293 294 /* index = 3*(T0 - T0_min) + 2 + T0_frac */ 295 i = sub(T0, T0_min, pOverflow); 296 temp2 = add(i, i, pOverflow); 297 i = add(temp2, i, pOverflow); 298 temp2 = add(i, 2, pOverflow); 299 index = add(temp2, T0_frac, pOverflow); 300 } 301 else 302 { 303 304 /* encoding with 4 bit resolution */ 305 306 tmp_lag = T0_prev; 307 temp1 = sub(tmp_lag, T0_min, pOverflow); 308 temp2 = sub(temp1, 5, pOverflow); 309 if (temp2 > 0) 310 tmp_lag = add(T0_min, 5, pOverflow); 311 temp1 = sub(T0_max, tmp_lag, pOverflow); 312 temp2 = sub(temp1, 4, pOverflow); 313 if (temp2 > 0) 314 tmp_lag = sub(T0_max, 4, pOverflow); 315 316 temp1 = add(T0, T0, pOverflow); 317 temp2 = add(temp1, T0, pOverflow); 318 uplag = add(temp2, T0_frac, pOverflow); 319 320 i = sub(tmp_lag, 2, pOverflow); 321 temp1 = add(i, i, pOverflow); 322 tmp_ind = add(temp1, i, pOverflow); 323 324 temp1 = sub(tmp_ind, uplag, pOverflow); 325 if (temp1 >= 0) 326 { 327 temp1 = sub(T0, tmp_lag, pOverflow); 328 index = add(temp1, 5, pOverflow); 329 } 330 else 331 { 332 333 i = add(tmp_lag, 1, pOverflow); 334 temp1 = add(i, i, pOverflow); 335 i = add(temp1, i, pOverflow); 336 337 if (sub(i, uplag, pOverflow) > 0) 338 { 339 temp1 = sub(uplag, tmp_ind, pOverflow); 340 index = add(temp1, 3, pOverflow); 341 } 342 else 343 { 344 temp1 = sub(T0, tmp_lag, pOverflow); 345 index = add(temp1, 11, pOverflow); 346 } 347 } 348 349 } /* end if (encoding with 4 bit resolution) */ 350 } /* end if (second of fourth subframe) */ 351 352 return index; 353 } 354 355 356 357
