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 Pathname: ./src/calc_gsfb_table.c 21 22 ------------------------------------------------------------------------------ 23 REVISION HISTORY 24 25 Description: Modified from original shareware code 26 27 Description: (1) Modified to bring in-line with PV standards 28 (2) Removed if(pFrameInfo->islong), only short windows will 29 call this routine from getics.c 30 31 Description: Modified per review comments 32 33 Who: Date: 34 Description: 35 36 ------------------------------------------------------------------------------ 37 INPUT AND OUTPUT DEFINITIONS 38 39 Inputs: 40 pFrameInfo = pointer to structure that holds information for current 41 frame. Data type FrameInfo 42 43 group[] = array that contains the grouping information of short 44 windows (stop index of windows in each group). 45 Data type Int 46 47 Local Stores/Buffers/Pointers Needed: 48 None 49 50 Global Stores/Buffers/Pointers Needed: 51 None 52 53 Outputs: 54 None 55 56 Pointers and Buffers Modified: 57 pFrameInfo -> frame_sfb_top contains the cumulative bandwidth of 58 scalefactor bands in each group 59 60 Local Stores Modified: 61 None 62 63 Global Stores Modified: 64 None 65 66 ------------------------------------------------------------------------------ 67 FUNCTION DESCRIPTION 68 69 This function is only invoked when short windows are present. It calculates 70 the number of groups in one frame, and the scalefactor bandwidth of each 71 scalefactor band in each group. 72 All windows within one group share the same scalefactors and are interleaved 73 on a scalefactor band basis. Within each group, the actual length of one 74 scalefactor band equals to the number of windows times the number of 75 coefficients in a regular scalefactor band. 76 77 ------------------------------------------------------------------------------ 78 REQUIREMENTS 79 80 This function shall replace the contents of pFrameInfo->frame_sfb_top 81 with the cumulative bandwidth of each scalefactor band in each group 82 83 ------------------------------------------------------------------------------ 84 REFERENCES 85 86 (1) MPEG-2 NBC Audio Decoder 87 "This software module was originally developed by AT&T, Dolby 88 Laboratories, Fraunhofer Gesellschaft IIS in the course of development 89 of the MPEG-2 NBC/MPEG-4 Audio standard ISO/IEC 13818-7, 14496-1,2 and 90 3. This software module is an implementation of a part of one or more 91 MPEG-2 NBC/MPEG-4 Audio tools as specified by the MPEG-2 NBC/MPEG-4 92 Audio standard. ISO/IEC gives users of the MPEG-2 NBC/MPEG-4 Audio 93 standards free license to this software module or modifications thereof 94 for use in hardware or software products claiming conformance to the 95 MPEG-2 NBC/MPEG-4 Audio standards. Those intending to use this software 96 module in hardware or software products are advised that this use may 97 infringe existing patents. The original developer of this software 98 module and his/her company, the subsequent editors and their companies, 99 and ISO/IEC have no liability for use of this software module or 100 modifications thereof in an implementation. Copyright is not released 101 for non MPEG-2 NBC/MPEG-4 Audio conforming products.The original 102 developer retains full right to use the code for his/her own purpose, 103 assign or donate the code to a third party and to inhibit third party 104 from using the code for non MPEG-2 NBC/MPEG-4 Audio conforming products. 105 This copyright notice must be included in all copies or derivative 106 works." 107 Copyright(c)1996. 108 109 (2) ISO/IEC 14496-3: 1999(E) 110 Subpart 4 p54. 4.5.2.3.2 decoding process 111 112 ------------------------------------------------------------------------------ 113 PSEUDO-CODE 114 115 offset = 0; 116 group_idx = 0; 117 118 DO 119 pFrameInfo->group_len[group_idx] = group[group_idx] - offset; 120 offset = group[group_idx]; 121 group_idx++; 122 123 WHILE (offset < NUM_SHORT_WINDOWS); 124 125 126 pFrameInfo->num_groups = group_idx; 127 128 pFrameSfbTop = pFrameInfo->frame_sfb_top; 129 offset = 0; 130 131 FOR (group_idx = 0; group_idx < pFrameInfo->num_groups; group_idx++) 132 133 len = pFrameInfo->group_len[group_idx]; 134 135 FOR (sfb = 0; sfb < pFrameInfo->sfb_per_win[group_idx]; sfb++) 136 137 offset += pFrameInfo->sfb_width_128[sfb] * len; 138 *pFrameSfbTop++ = offset; 139 140 ENDFOR 141 142 ENDFOR 143 144 ------------------------------------------------------------------------------ 145 RESOURCES USED 146 When the code is written for a specific target processor the 147 the resources used should be documented below. 148 149 STACK USAGE: [stack count for this module] + [variable to represent 150 stack usage for each subroutine called] 151 152 where: [stack usage variable] = stack usage for [subroutine 153 name] (see [filename].ext) 154 155 DATA MEMORY USED: x words 156 157 PROGRAM MEMORY USED: x words 158 159 CLOCK CYCLES: [cycle count equation for this module] + [variable 160 used to represent cycle count for each subroutine 161 called] 162 163 where: [cycle count variable] = cycle count for [subroutine 164 name] (see [filename].ext) 165 166 ------------------------------------------------------------------------------ 167 */ 168 169 170 /*---------------------------------------------------------------------------- 171 ; INCLUDES 172 ----------------------------------------------------------------------------*/ 173 #include "pv_audio_type_defs.h" 174 #include "huffman.h" 175 #include "aac_mem_funcs.h" 176 177 /*---------------------------------------------------------------------------- 178 ; MACROS 179 ; Define module specific macros here 180 ----------------------------------------------------------------------------*/ 181 182 /*---------------------------------------------------------------------------- 183 ; DEFINES 184 ; Include all pre-processor statements here. Include conditional 185 ; compile variables also. 186 ----------------------------------------------------------------------------*/ 187 188 /*---------------------------------------------------------------------------- 189 ; LOCAL FUNCTION DEFINITIONS 190 ; Function Prototype declaration 191 ----------------------------------------------------------------------------*/ 192 193 /*---------------------------------------------------------------------------- 194 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS 195 ; Variable declaration - defined here and used outside this module 196 ----------------------------------------------------------------------------*/ 197 198 /*---------------------------------------------------------------------------- 199 ; EXTERNAL FUNCTION REFERENCES 200 ; Declare functions defined elsewhere and referenced in this module 201 ----------------------------------------------------------------------------*/ 202 203 /*---------------------------------------------------------------------------- 204 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES 205 ; Declare variables used in this module but defined elsewhere 206 ----------------------------------------------------------------------------*/ 207 208 /*---------------------------------------------------------------------------- 209 ; FUNCTION CODE 210 ----------------------------------------------------------------------------*/ 211 void calc_gsfb_table( 212 FrameInfo *pFrameInfo, 213 Int group[]) 214 { 215 216 Int group_idx; 217 Int offset; 218 Int *pFrameSfbTop; 219 Int *pSfbWidth128; 220 Int sfb; 221 Int nsfb; 222 Int len; 223 Int ngroups; 224 225 /* clear out the default values set by infoinit */ 226 /* */ 227 pv_memset(pFrameInfo->frame_sfb_top, 228 0, 229 MAXBANDS*sizeof(pFrameInfo->frame_sfb_top[0])); 230 /* */ 231 /* first calculate the group length*/ 232 offset = 0; 233 ngroups = 0; 234 do 235 { 236 pFrameInfo->group_len[ngroups] = group[ngroups] - offset; 237 offset = group[ngroups]; 238 ngroups++; 239 240 } 241 while (offset < NUM_SHORT_WINDOWS); 242 243 244 /* calculate the cumulative scalefactor bandwidth for one frame */ 245 pFrameInfo->num_groups = ngroups; 246 247 pFrameSfbTop = pFrameInfo->frame_sfb_top; 248 offset = 0; 249 250 251 for (group_idx = 0; group_idx < ngroups; group_idx++) 252 { 253 len = pFrameInfo->group_len[ group_idx]; 254 nsfb = pFrameInfo->sfb_per_win[group_idx]; 255 256 pSfbWidth128 = pFrameInfo->sfb_width_128; 257 258 for (sfb = nsfb; sfb > 0; sfb--) 259 { 260 offset += *pSfbWidth128++ * len; 261 *pFrameSfbTop++ = offset; 262 } 263 } 264 265 266 } /* calc_gsfb_table */ 267 268
