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/preemph.c 35 Functions: 36 37 Date: 02/04/2002 38 39 ------------------------------------------------------------------------------ 40 REVISION HISTORY 41 42 Description: Removed the functions preemphasis_init and preemphasis_exit. 43 The preemphasis related structure is no longer dynamically allocated. 44 Placed file in the appropriate PV Software Template format. 45 46 Description: Changed to accept the pOverflow flag for EPOC compatibility. 47 48 Description: Replaced OSCL mem type functions and eliminated include 49 files that now are chosen by OSCL definitions 50 51 Description: Replaced "int" and/or "char" with OSCL defined types. 52 53 Description: 54 55 ------------------------------------------------------------------------------ 56 MODULE DESCRIPTION 57 58 Purpose : Preemphasis filtering 59 Description : Filtering through 1 - g z^-1 60 61 ------------------------------------------------------------------------------ 62 */ 63 64 /*---------------------------------------------------------------------------- 65 ; INCLUDES 66 ----------------------------------------------------------------------------*/ 67 #include "preemph.h" 68 #include "typedef.h" 69 #include "basic_op.h" 70 71 /*---------------------------------------------------------------------------- 72 ; MACROS 73 ; Define module specific macros here 74 ----------------------------------------------------------------------------*/ 75 76 /*---------------------------------------------------------------------------- 77 ; DEFINES 78 ; Include all pre-processor statements here. Include conditional 79 ; compile variables also. 80 ----------------------------------------------------------------------------*/ 81 82 /*---------------------------------------------------------------------------- 83 ; LOCAL FUNCTION DEFINITIONS 84 ; Function Prototype declaration 85 ----------------------------------------------------------------------------*/ 86 87 /*---------------------------------------------------------------------------- 88 ; LOCAL VARIABLE DEFINITIONS 89 ; Variable declaration - defined here and used outside this module 90 ----------------------------------------------------------------------------*/ 91 92 93 /* 94 ------------------------------------------------------------------------------ 95 FUNCTION NAME: preemphasis_reset 96 ------------------------------------------------------------------------------ 97 INPUT AND OUTPUT DEFINITIONS 98 99 Inputs: 100 st -- double pointer to preemphasisState 101 102 Outputs: 103 st -- double ponter to preemphasisState 104 105 Returns: 106 -1 if an error occurs 107 0 if OK 108 109 Global Variables Used: 110 None 111 112 Local Variables Needed: 113 None 114 115 ------------------------------------------------------------------------------ 116 FUNCTION DESCRIPTION 117 118 Initializes state memory to zero 119 ------------------------------------------------------------------------------ 120 REQUIREMENTS 121 122 None 123 124 ------------------------------------------------------------------------------ 125 REFERENCES 126 127 preemph.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 128 129 ------------------------------------------------------------------------------ 130 PSEUDO-CODE 131 132 133 ------------------------------------------------------------------------------ 134 RESOURCES USED [optional] 135 136 When the code is written for a specific target processor the 137 the resources used should be documented below. 138 139 HEAP MEMORY USED: x bytes 140 141 STACK MEMORY USED: x bytes 142 143 CLOCK CYCLES: (cycle count equation for this function) + (variable 144 used to represent cycle count for each subroutine 145 called) 146 where: (cycle count variable) = cycle count for [subroutine 147 name] 148 149 ------------------------------------------------------------------------------ 150 CAUTION [optional] 151 [State any special notes, constraints or cautions for users of this function] 152 153 ------------------------------------------------------------------------------ 154 */ 155 156 Word16 preemphasis_reset(preemphasisState *state) 157 { 158 if (state == (preemphasisState *) NULL) 159 { 160 /* fprintf(stderr, "preemphasis_reset: invalid parameter\n"); */ 161 return -1; 162 } 163 164 state->mem_pre = 0; 165 166 return 0; 167 } 168 169 /* 170 ------------------------------------------------------------------------------ 171 FUNCTION NAME: preemphasis 172 ------------------------------------------------------------------------------ 173 INPUT AND OUTPUT DEFINITIONS 174 175 Inputs: 176 st -- Pointer to preemphasisState -- preemphasis filter state 177 signal -- array of type Word16 -- input signal overwritten by the output 178 g -- Word16 -- preemphasis coefficient 179 L -- Word16 -- size of filtering 180 181 Outputs: 182 st -- Pointer to preemphasisState -- preemphasis filter state 183 signal -- array of type Word16 -- input signal overwritten by the output 184 pOverflow -- pointer to type Flag -- overflow indicator 185 Returns: 186 None 187 188 Global Variables Used: 189 None 190 191 Local Variables Needed: 192 None 193 194 ------------------------------------------------------------------------------ 195 FUNCTION DESCRIPTION 196 197 Filtering through 1 - g z^-1 198 ------------------------------------------------------------------------------ 199 REQUIREMENTS 200 201 None 202 203 ------------------------------------------------------------------------------ 204 REFERENCES 205 206 preemph.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 207 208 ------------------------------------------------------------------------------ 209 PSEUDO-CODE 210 211 212 ------------------------------------------------------------------------------ 213 RESOURCES USED [optional] 214 215 When the code is written for a specific target processor the 216 the resources used should be documented below. 217 218 HEAP MEMORY USED: x bytes 219 220 STACK MEMORY USED: x bytes 221 222 CLOCK CYCLES: (cycle count equation for this function) + (variable 223 used to represent cycle count for each subroutine 224 called) 225 where: (cycle count variable) = cycle count for [subroutine 226 name] 227 228 ------------------------------------------------------------------------------ 229 CAUTION [optional] 230 [State any special notes, constraints or cautions for users of this function] 231 232 ------------------------------------------------------------------------------ 233 */ 234 235 236 void preemphasis( 237 preemphasisState *st, /* (i/o) : preemphasis filter state */ 238 Word16 *signal, /* (i/o) : input signal overwritten by the output */ 239 Word16 g, /* (i) : preemphasis coefficient */ 240 Word16 L, /* (i) : size of filtering */ 241 Flag *pOverflow /* (o) : overflow indicator */ 242 ) 243 { 244 Word16 *p1; 245 Word16 *p2; 246 Word16 temp; 247 Word16 temp2; 248 Word16 i; 249 250 p1 = signal + L - 1; 251 p2 = p1 - 1; 252 temp = *p1; 253 254 for (i = 0; i <= L - 2; i++) 255 { 256 temp2 = mult(g, *(p2--), pOverflow); 257 *p1 = sub(*p1, temp2, pOverflow); 258 259 p1--; 260 } 261 262 temp2 = mult(g, st->mem_pre, pOverflow); 263 264 *p1 = sub(*p1, temp2, pOverflow); 265 266 st->mem_pre = temp; 267 268 return; 269 } 270 271 272 273
