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 Pathname: ./audio/gsm-amr/c/src/gmed_n.c 31 32 ------------------------------------------------------------------------------ 33 REVISION HISTORY 34 35 Description: Put file into template and first pass at optimization. 36 37 Description: Made changes based on comments from the review meeting. Used 38 pointers instead of index addressing in the arrays. 39 40 Description: Synchronized file with UMTS version 3.2.0. Updated coding 41 template. Removed unncessary include files. 42 43 Description: Replaced "int" and/or "char" with OSCL defined types. 44 45 Who: Date: 46 Description: 47 48 ------------------------------------------------------------------------------ 49 */ 50 51 /*---------------------------------------------------------------------------- 52 ; INCLUDES 53 ----------------------------------------------------------------------------*/ 54 #include "gmed_n.h" 55 #include "typedef.h" 56 57 /*---------------------------------------------------------------------------- 58 ; MACROS 59 ; Define module specific macros here 60 ----------------------------------------------------------------------------*/ 61 62 63 /*---------------------------------------------------------------------------- 64 ; DEFINES 65 ; Include all pre-processor statements here. Include conditional 66 ; compile variables also. 67 ----------------------------------------------------------------------------*/ 68 #define NMAX 9 /* largest N used in median calculation */ 69 70 /*---------------------------------------------------------------------------- 71 ; LOCAL FUNCTION DEFINITIONS 72 ; Function Prototype declaration 73 ----------------------------------------------------------------------------*/ 74 75 76 /*---------------------------------------------------------------------------- 77 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS 78 ; Variable declaration - defined here and used outside this module 79 ----------------------------------------------------------------------------*/ 80 81 82 /* 83 ------------------------------------------------------------------------------ 84 FUNCTION NAME: gmed_n 85 ------------------------------------------------------------------------------ 86 INPUT AND OUTPUT DEFINITIONS 87 88 Inputs: 89 ind = input values (Word16) 90 n = number of inputs to find the median (Word16) 91 92 Returns: 93 median value. 94 95 Outputs: 96 None. 97 98 Global Variables Used: 99 None. 100 101 Local Variables Needed: 102 None. 103 104 ------------------------------------------------------------------------------ 105 FUNCTION DESCRIPTION 106 107 This function calculates N-point median of a data set. This routine is only 108 valid for a odd number of gains (n <= NMAX). 109 110 ------------------------------------------------------------------------------ 111 REQUIREMENTS 112 113 None. 114 115 ------------------------------------------------------------------------------ 116 REFERENCES 117 118 gmed_n.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 119 120 ------------------------------------------------------------------------------ 121 PSEUDO-CODE 122 123 Word16 gmed_n ( // o : The median value (0...N-1) 124 Word16 ind[], // i : Past gain values 125 Word16 n // i : The number of gains; this routine 126 // is only valid for a odd number of gains 127 // (n <= NMAX) 128 ) 129 { 130 Word16 i, j, ix = 0; 131 Word16 max; 132 Word16 medianIndex; 133 Word16 tmp[NMAX]; 134 Word16 tmp2[NMAX]; 135 136 for (i = 0; i < n; i++) 137 { 138 tmp2[i] = ind[i]; 139 } 140 141 for (i = 0; i < n; i++) 142 { 143 max = -32767; 144 for (j = 0; j < n; j++) 145 { 146 if (sub (tmp2[j], max) >= 0) 147 { 148 max = tmp2[j]; 149 ix = j; 150 } 151 } 152 tmp2[ix] = -32768; 153 tmp[i] = ix; 154 } 155 156 medianIndex=tmp[ shr(n,1) ]; // account for complex addressing 157 return (ind[medianIndex]); 158 } 159 160 ------------------------------------------------------------------------------ 161 RESOURCES USED [optional] 162 163 When the code is written for a specific target processor the 164 the resources used should be documented below. 165 166 HEAP MEMORY USED: x bytes 167 168 STACK MEMORY USED: x bytes 169 170 CLOCK CYCLES: (cycle count equation for this function) + (variable 171 used to represent cycle count for each subroutine 172 called) 173 where: (cycle count variable) = cycle count for [subroutine 174 name] 175 176 ------------------------------------------------------------------------------ 177 CAUTION [optional] 178 [State any special notes, constraints or cautions for users of this function] 179 180 ------------------------------------------------------------------------------ 181 */ 182 183 Word16 gmed_n( /* o : the median value */ 184 Word16 ind[], /* i : input values */ 185 Word16 n /* i : number of inputs */ 186 ) 187 { 188 Word16 i, j, ix = 0; 189 Word16 max; 190 Word16 medianIndex; 191 Word16 tmp[NMAX]; 192 Word16 tmp2[NMAX]; 193 194 for (i = 0; i < n; i++) 195 { 196 *(tmp2 + i) = *(ind + i); 197 } 198 199 for (i = 0; i < n; i++) 200 { 201 max = -32767; 202 for (j = 0; j < n; j++) 203 { 204 if (*(tmp2 + j) >= max) 205 { 206 max = *(tmp2 + j); 207 ix = j; 208 } 209 } 210 *(tmp2 + ix) = -32768; 211 *(tmp + i) = ix; 212 } 213 214 medianIndex = *(tmp + (n >> 1)); /* account for complex addressing */ 215 216 return (*(ind + medianIndex)); 217 } 218 219
