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/dec_lag6.c 35 Functions: Dec_lag6 36 37 Date: 01/31/2002 38 39 ------------------------------------------------------------------------------ 40 REVISION HISTORY 41 42 Description: 43 (1) Updated to accept new parameter, Flag *pOverflow. 44 (2) Placed file in the proper PV Software template. 45 46 Description: 47 (1) Removed "count.h" and "basic_op.h" and replaced with individual include 48 files (add.h, sub.h, etc.) 49 50 Description: 51 (1) Removed optimization -- mult(i, 3, pOverflow) is NOT the same as adding 52 i to itself 3 times. The reason is because the mult function does a 53 right shift by 15, which will obliterate smaller numbers. 54 55 Description: Replaced "int" and/or "char" with OSCL defined types. 56 57 Description: 58 59 ------------------------------------------------------------------------------ 60 INPUT AND OUTPUT DEFINITIONS 61 62 Inputs: 63 index -- Word16 -- received pitch index 64 pit_min -- Word16 -- minimum pitch lag 65 pit_max -- Word16 -- maximum pitch lag 66 i_subfr -- Word16 -- subframe flag 67 T0 -- Pointer to type Word16 -- integer part of pitch lag 68 69 Outputs: 70 71 T0 -- Pointer to type Word16 -- integer part of pitch lag 72 T0_frac -- Pointer to type Word16 -- fractional part of pitch lag 73 pOverflow -- Pointer to type Flag -- Flag set when overflow occurs 74 75 Returns: 76 None. 77 78 Global Variables Used: 79 None 80 81 Local Variables Needed: 82 None 83 84 ------------------------------------------------------------------------------ 85 FUNCTION DESCRIPTION 86 87 PURPOSE: Decoding of fractional pitch lag with 1/6 resolution. 88 Extract the integer and fraction parts of the pitch lag from 89 the received adaptive codebook index. 90 91 See "Enc_lag6.c" for more details about the encoding procedure. 92 93 The fractional lag in 1st and 3rd subframes is encoded with 9 bits 94 while that in 2nd and 4th subframes is relatively encoded with 6 bits. 95 Note that in relative encoding only 61 values are used. If the 96 decoder receives 61, 62, or 63 as the relative pitch index, it means 97 that a transmission error occurred. In this case, the pitch lag from 98 previous subframe (actually from previous frame) is used. 99 100 ------------------------------------------------------------------------------ 101 REQUIREMENTS 102 103 104 105 ------------------------------------------------------------------------------ 106 REFERENCES 107 108 dec_lag6.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 109 110 ------------------------------------------------------------------------------ 111 PSEUDO-CODE 112 113 114 115 ------------------------------------------------------------------------------ 116 RESOURCES USED 117 When the code is written for a specific target processor the 118 the resources used should be documented below. 119 120 STACK USAGE: [stack count for this module] + [variable to represent 121 stack usage for each subroutine called] 122 123 where: [stack usage variable] = stack usage for [subroutine 124 name] (see [filename].ext) 125 126 DATA MEMORY USED: x words 127 128 PROGRAM MEMORY USED: x words 129 130 CLOCK CYCLES: [cycle count equation for this module] + [variable 131 used to represent cycle count for each subroutine 132 called] 133 134 where: [cycle count variable] = cycle count for [subroutine 135 name] (see [filename].ext) 136 137 ------------------------------------------------------------------------------ 138 */ 139 140 141 /*---------------------------------------------------------------------------- 142 ; INCLUDES 143 ----------------------------------------------------------------------------*/ 144 #include "dec_lag6.h" 145 #include "typedef.h" 146 #include "basic_op.h" 147 148 /*---------------------------------------------------------------------------- 149 ; MACROS 150 ; Define module specific macros here 151 ----------------------------------------------------------------------------*/ 152 153 154 /*---------------------------------------------------------------------------- 155 ; DEFINES 156 ; Include all pre-processor statements here. Include conditional 157 ; compile variables also. 158 ----------------------------------------------------------------------------*/ 159 160 /*---------------------------------------------------------------------------- 161 ; LOCAL FUNCTION DEFINITIONS 162 ; Function Prototype declaration 163 ----------------------------------------------------------------------------*/ 164 165 166 /*---------------------------------------------------------------------------- 167 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS 168 ; Variable declaration - defined here and used outside this module 169 ----------------------------------------------------------------------------*/ 170 171 /*---------------------------------------------------------------------------- 172 ; EXTERNAL FUNCTION REFERENCES 173 ; Declare functions defined elsewhere and referenced in this module 174 ----------------------------------------------------------------------------*/ 175 176 /*---------------------------------------------------------------------------- 177 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES 178 ; Declare variables used in this module but defined elsewhere 179 ----------------------------------------------------------------------------*/ 180 181 /*---------------------------------------------------------------------------- 182 ; FUNCTION CODE 183 ----------------------------------------------------------------------------*/ 184 185 void Dec_lag6( 186 Word16 index, /* input : received pitch index */ 187 Word16 pit_min, /* input : minimum pitch lag */ 188 Word16 pit_max, /* input : maximum pitch lag */ 189 Word16 i_subfr, /* input : subframe flag */ 190 Word16 *T0, /* in/out: integer part of pitch lag */ 191 Word16 *T0_frac, /* output: fractional part of pitch lag */ 192 Flag *pOverflow /* o : Flag set when overflow occurs */ 193 ) 194 { 195 Word16 i; 196 Word16 T0_min; 197 Word16 T0_max; 198 Word16 k; 199 Word16 w; 200 201 if (i_subfr == 0) /* if 1st or 3rd subframe */ 202 { 203 if (index < 463) 204 { 205 /* T0 = (index+5)/6 + 17 */ 206 i = index + 5; 207 i = 208 mult( 209 i, 210 5462, 211 pOverflow); 212 213 i = 214 add( 215 i, 216 17, 217 pOverflow); 218 219 *T0 = i; 220 221 /* i = 3* (*T0) */ 222 223 i = add(i, i, pOverflow); 224 i = add(i, *T0, pOverflow); 225 226 /* *T0_frac = index - T0*6 + 105 */ 227 228 i = 229 add( 230 i, 231 i, 232 pOverflow); 233 234 i = 235 sub( 236 index, 237 i, 238 pOverflow); 239 240 *T0_frac = 241 add( 242 i, 243 105, 244 pOverflow); 245 } 246 else 247 { 248 *T0 = 249 sub( 250 index, 251 368, 252 pOverflow); 253 254 *T0_frac = 0; 255 } 256 } 257 else /* second or fourth subframe */ 258 { 259 /* find T0_min and T0_max for 2nd (or 4th) subframe */ 260 261 T0_min = 262 sub( 263 *T0, 264 5, 265 pOverflow); 266 267 if (T0_min < pit_min) 268 { 269 T0_min = pit_min; 270 } 271 272 T0_max = 273 add( 274 T0_min, 275 9, 276 pOverflow); 277 278 if (T0_max > pit_max) 279 { 280 T0_max = pit_max; 281 282 T0_min = 283 sub( 284 T0_max, 285 9, 286 pOverflow); 287 } 288 289 /* i = (index+5)/6 - 1 */ 290 i = 291 add( 292 index, 293 5, 294 pOverflow); 295 296 i = 297 mult( 298 i, 299 5462, 300 pOverflow); 301 302 i = 303 sub( 304 i, 305 1, 306 pOverflow); 307 308 *T0 = 309 add( 310 i, 311 T0_min, 312 pOverflow); 313 314 /* i = 3* (*T0) */ 315 316 w = add(i, i, pOverflow); 317 i = add(i, w, pOverflow); 318 319 i = 320 add( 321 i, 322 i, 323 pOverflow); 324 325 k = 326 sub( 327 index, 328 3, 329 pOverflow); 330 331 *T0_frac = 332 sub( 333 k, 334 i, 335 pOverflow); 336 } 337 } 338
