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 Filename: d4_17pf.cpp 35 Functions: decode_4i40_17bits 36 37 ------------------------------------------------------------------------------ 38 MODULE DESCRIPTION 39 40 41 FUNCTION: decode_4i40_17bits (decod_ACELP()) 42 43 PURPOSE: Algebraic codebook decoder. For details about the encoding see 44 c4_17pf.c 45 */ 46 47 /*---------------------------------------------------------------------------- 48 ; INCLUDES 49 ----------------------------------------------------------------------------*/ 50 #include "typedef.h" 51 #include "basic_op.h" 52 #include "cnst.h" 53 #include "d4_17pf.h" 54 55 /*--------------------------------------------------------------------------*/ 56 #ifdef __cplusplus 57 extern "C" 58 { 59 #endif 60 61 /*---------------------------------------------------------------------------- 62 ; MACROS 63 ; Define module specific macros here 64 ----------------------------------------------------------------------------*/ 65 66 /*---------------------------------------------------------------------------- 67 ; DEFINES 68 ; Include all pre-processor statements here. Include conditional 69 ; compile variables also. 70 ----------------------------------------------------------------------------*/ 71 #define NB_PULSE 4 /* number of pulses */ 72 73 74 /*---------------------------------------------------------------------------- 75 ; LOCAL FUNCTION DEFINITIONS 76 ; Function Prototype declaration 77 ----------------------------------------------------------------------------*/ 78 79 /*---------------------------------------------------------------------------- 80 ; LOCAL VARIABLE DEFINITIONS 81 ; Variable declaration - defined here and used outside this module 82 ----------------------------------------------------------------------------*/ 83 84 /*---------------------------------------------------------------------------- 85 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES 86 ; Declare variables used in this module but defined elsewhere 87 ----------------------------------------------------------------------------*/ 88 89 /*--------------------------------------------------------------------------*/ 90 #ifdef __cplusplus 91 } 92 #endif 93 94 /* 95 ------------------------------------------------------------------------------ 96 FUNCTION NAME: decode_4i40_17bits 97 ------------------------------------------------------------------------------ 98 INPUT AND OUTPUT DEFINITIONS 99 100 Inputs: 101 sign -- Word16 -- signs of 3 pulses. 102 index -- Word16 -- Positions of the 3 pulses. 103 104 Outputs: 105 cod[] -- array of type Word16 -- algebraic (fixed) codebook excitation 106 107 Returns: 108 None 109 110 Global Variables Used: 111 None 112 113 Local Variables Needed: 114 None 115 116 ------------------------------------------------------------------------------ 117 FUNCTION DESCRIPTION 118 119 120 ------------------------------------------------------------------------------ 121 REQUIREMENTS 122 123 None decode_3i40_14bits(Word16 sign,Word16 index,Word16 cod[])124 125 ------------------------------------------------------------------------------ 126 REFERENCES 127 128 d4_17pf.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 129 130 ------------------------------------------------------------------------------ 131 PSEUDO-CODE 132 133 134 ------------------------------------------------------------------------------ 135 CAUTION [optional] 136 [State any special notes, constraints or cautions for users of this function] 137 138 ------------------------------------------------------------------------------ 139 */ 140 141 void decode_4i40_17bits( 142 Word16 sign, /* i : signs of 4 pulses. */ 143 Word16 index, /* i : Positions of the 4 pulses. */ 144 const Word16* dgray_ptr, /* i : Pointer to read-only table */ 145 Word16 cod[] /* o : algebraic (fixed) codebook excitation */ 146 ) 147 { 148 Word16 i; 149 Word16 j; 150 151 Word16 pos[NB_PULSE]; 152 153 /* Index is a 13-bit value. 3 bits each correspond to the 154 * positions 0-2, with 4 bits allocated for position 3. 155 * 156 * 157 * [][][][] [][][] [][][] [][][] 158 * | | | | 159 * | | | | 160 * pos3 pos2 pos1 pos0 161 */ 162 163 /* Decode the positions */ 164 165 i = index & 0x7; 166 167 i = dgray_ptr[i]; 168 169 pos[0] = i * 5; /* pos0 =i*5 */ 170 171 172 index >>= 3; 173 174 i = index & 0x7; 175 176 i = dgray_ptr[i]; 177 178 pos[1] = i * 5 + 1; /* pos1 =i*5+1 */ 179 180 181 182 index >>= 3; 183 184 i = index & 0x7; 185 186 i = dgray_ptr[i]; 187 188 pos[2] = i * 5 + 2; /* pos2 =i*5+2 */ 189 190 191 192 193 194 index >>= 3; 195 196 j = index & 0x1; 197 198 index >>= 1; 199 200 i = index & 0x7; 201 202 i = dgray_ptr[i]; 203 204 pos[3] = i * 5 + 3 + j; /* pos3 =i*5+3+j */ 205 206 207 /* decode the signs and build the codeword */ 208 209 for (i = 0; i < L_SUBFR; i++) 210 { 211 cod[i] = 0; 212 } 213 214 for (j = 0; j < NB_PULSE; j++) 215 { 216 i = sign & 0x1; 217 218 /* This line is equivalent to... 219 * 220 * 221 * if (i == 1) 222 * { 223 * cod[pos[j]] = 8191; 224 * } 225 * if (i == 0) 226 * { 227 * cod[pos[j]] = -8192; 228 * } 229 */ 230 231 cod[pos[j]] = i * 16383 - 8192; 232 233 sign >>= 1; 234 } 235 236 return; 237 } 238