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 ------------------------------------------------------------------------------ 20 21 PacketVideo Corp. 22 MP3 Decoder Library 23 24 Filename: pvmp3_get_scale_factors.cpp 25 26 Date: 09/21/2007 27 28 ------------------------------------------------------------------------------ 29 REVISION HISTORY 30 31 32 Description: 33 34 ------------------------------------------------------------------------------ 35 INPUT AND OUTPUT DEFINITIONS 36 37 Input 38 mp3ScaleFactors *scalefac, 39 mp3SideInfo *si, side info 40 int32 gr, granule 41 int32 ch, channel 42 tbits *pMainData bit stream 43 44 Returns 45 46 mp3ScaleFactors *scalefac, scale factors 47 48 ------------------------------------------------------------------------------ 49 FUNCTION DESCRIPTION 50 51 get scale factors 52 53 ------------------------------------------------------------------------------ 54 REQUIREMENTS 55 56 57 ------------------------------------------------------------------------------ 58 REFERENCES 59 60 [1] ISO MPEG Audio Subgroup Software Simulation Group (1996) 61 ISO 13818-3 MPEG-2 Audio Decoder - Lower Sampling Frequency Extension 62 63 ------------------------------------------------------------------------------ 64 PSEUDO-CODE 65 66 ------------------------------------------------------------------------------ 67 */ 68 69 70 /*---------------------------------------------------------------------------- 71 ; INCLUDES 72 ----------------------------------------------------------------------------*/ 73 74 #include "pvmp3_get_scale_factors.h" 75 #include "pvmp3_getbits.h" 76 #include "mp3_mem_funcs.h" 77 78 /*---------------------------------------------------------------------------- 79 ; MACROS 80 ; Define module specific macros here 81 ----------------------------------------------------------------------------*/ 82 83 84 /*---------------------------------------------------------------------------- 85 ; DEFINES 86 ; Include all pre-processor statements here. Include conditional 87 ; compile variables also. 88 ----------------------------------------------------------------------------*/ 89 #define Qfmt_28(a)(int32(double(0x10000000)*a)) 90 91 /*---------------------------------------------------------------------------- 92 ; LOCAL FUNCTION DEFINITIONS 93 ; Function Prototype declaration 94 ----------------------------------------------------------------------------*/ 95 96 /*---------------------------------------------------------------------------- 97 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS 98 ; Variable declaration - defined here and used outside this module 99 ----------------------------------------------------------------------------*/ 100 const int32 slen[2][16] = 101 { 102 {0, 0, 0, 0, 3, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4}, 103 {0, 1, 2, 3, 0, 1, 2, 3, 1, 2, 3, 1, 2, 3, 2, 3} 104 }; 105 106 const struct 107 { 108 int32 l[5]; 109 int32 s[3]; 110 } sfbtable = 111 { 112 {0, 6, 11, 16, 21}, 113 {0, 6, 12} 114 }; 115 116 const int32 long_sfbtable[4] = { 6, 5, 5, 5}; 117 118 /*---------------------------------------------------------------------------- 119 ; EXTERNAL FUNCTION REFERENCES 120 ; Declare functions defined elsewhere and referenced in this module 121 ----------------------------------------------------------------------------*/ 122 123 /*---------------------------------------------------------------------------- 124 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES 125 ; Declare variables used in this module but defined elsewhere 126 ----------------------------------------------------------------------------*/ 127 128 /*---------------------------------------------------------------------------- 129 ; FUNCTION CODE 130 ----------------------------------------------------------------------------*/ 131 132 void pvmp3_get_scale_factors(mp3ScaleFactors *scalefac, 133 mp3SideInfo *si, 134 int32 gr, 135 int32 ch, 136 tmp3Bits *pMainData) 137 { 138 int32 sfb; 139 int32 i; 140 int32 window; 141 granuleInfo *gr_info = &(si->ch[ch].gran[gr]); 142 143 if (gr_info->window_switching_flag && (gr_info->block_type == 2)) 144 { 145 if (gr_info->mixed_block_flag) 146 { /* MIXED */ 147 for (sfb = 0; sfb < 8; sfb++) 148 { 149 scalefac->l[sfb] = getNbits(pMainData, slen[0][gr_info->scalefac_compress]); 150 } 151 152 for (sfb = 3; sfb < 6; sfb++) 153 { 154 for (window = 0; window < 3; window++) 155 { 156 scalefac->s[window][sfb] = getNbits(pMainData, slen[0][gr_info->scalefac_compress]); 157 } 158 } 159 for (sfb = 6; sfb < 12; sfb++) 160 { 161 for (window = 0; window < 3; window++) 162 { 163 scalefac->s[window][sfb] = getNbits(pMainData, slen[1][gr_info->scalefac_compress]); 164 } 165 } 166 } 167 else 168 { /* SHORT*/ 169 for (i = 0; i < 2; i++) 170 { 171 for (sfb = sfbtable.s[i]; sfb < sfbtable.s[i+1]; sfb++) 172 { 173 for (window = 0; window < 3; window++) 174 { 175 scalefac->s[window][sfb] = getNbits(pMainData, slen[i][gr_info->scalefac_compress]); 176 } 177 } 178 } 179 } 180 181 scalefac->s[0][12] = 0; /* sfb = 12 win= 0 */ 182 scalefac->s[1][12] = 0; /* sfb = 12 win= 1 */ 183 scalefac->s[2][12] = 0; /* sfb = 12 win= 2 */ 184 } 185 else 186 { /* LONG types 0,1,3 */ 187 188 int32 *ptr = &scalefac->l[0]; 189 190 for (i = 0; i < 4; i++) 191 { 192 int32 tmp4 = long_sfbtable[i]; 193 194 if ((si->ch[ch].scfsi[i] == 0) || (gr == 0)) 195 { 196 int32 tmp1 = slen[(i>>1)][gr_info->scalefac_compress]; 197 198 if (tmp1) 199 { 200 int32 tmp2 = tmp1 * tmp4; 201 uint32 tmp3 = getNbits(pMainData, tmp2); 202 tmp4 = 32 - tmp1; 203 for (; tmp2 > 0; tmp2 -= tmp1) 204 { 205 *(ptr++) = (tmp3 << (32 - tmp2)) >> tmp4; 206 } 207 } 208 else 209 { 210 for (sfb = tmp4; sfb != 0; sfb--) 211 { 212 *(ptr++) = 0; 213 } 214 215 } 216 } 217 else 218 { 219 ptr += tmp4; 220 } 221 } 222 scalefac->l[21] = 0; 223 scalefac->l[22] = 0; 224 } 225 } 226 227
