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_imdct_synth.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 int32 in[], Pointer to spec values of current channel 39 int32 overlap[], Pointer to overlap values of current channel 40 uint32 blk_type, Block type 41 int16 mx_band, In case of mixed blocks, # of bands with long 42 blocks (2 or 4) else 0 43 int32 *Scratch_mem 44 Returns 45 46 int32 in[], 47 48 ------------------------------------------------------------------------------ 49 FUNCTION DESCRIPTION 50 51 The frequency lines are preprocessed by the "alias reduction" scheme 52 and fed into the IMDCT matrix, each 18 into one transform block. 53 The first half of the output values are added to the stored overlap 54 values from the last block. These values are new output values and 55 are input values for the polyphase filterbank. The second half of the 56 output values is stored for overlap with the next data granule. 57 The number of windowed samples is 12 for short blocks, and 36 for long 58 blocks 59 60 Windowing 61 62 Depending on window_switching_flag[gr][ch], block_type[gr][ch] and 63 mixed_block_flag[gr][ch] different shapes of windows are used. 64 normal window 65 start window 66 stop window 67 short windows 68 Each of the three short blocks is windowed separately. 69 The windowed short blocks must be overlapped and concatenated. 70 71 Overlapping and adding with previous block 72 73 The first half (18 values) of the current block (36 values) has to be 74 overlapped with the second half of the previous block. The second half 75 of the current block has to be stored for overlapping with the next block 76 77 ------------------------------------------------------------------------------ 78 REQUIREMENTS 79 80 81 ------------------------------------------------------------------------------ 82 REFERENCES 83 84 [1] ISO MPEG Audio Subgroup Software Simulation Group (1996) 85 ISO 13818-3 MPEG-2 Audio Decoder - Lower Sampling Frequency Extension 86 87 ------------------------------------------------------------------------------ 88 PSEUDO-CODE 89 90 ------------------------------------------------------------------------------ 91 */ 92 93 94 /*---------------------------------------------------------------------------- 95 ; INCLUDES 96 ----------------------------------------------------------------------------*/ 97 98 #include "pvmp3_imdct_synth.h" 99 #include "pv_mp3dec_fxd_op.h" 100 #include "pvmp3_dec_defs.h" 101 #include "pvmp3_mdct_18.h" 102 #include "pvmp3_mdct_6.h" 103 #include "mp3_mem_funcs.h" 104 105 106 107 /*---------------------------------------------------------------------------- 108 ; MACROS 109 ; Define module specific macros here 110 ----------------------------------------------------------------------------*/ 111 112 113 /*---------------------------------------------------------------------------- 114 ; DEFINES 115 ; Include all pre-processor statements here. Include conditional 116 ; compile variables also. 117 ----------------------------------------------------------------------------*/ 118 #define LONG 0 119 #define START 1 120 #define SHORT 2 121 #define STOP 3 122 123 /*---------------------------------------------------------------------------- 124 ; LOCAL FUNCTION DEFINITIONS 125 ; Function Prototype declaration 126 ----------------------------------------------------------------------------*/ 127 128 /*---------------------------------------------------------------------------- 129 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS 130 ; Variable declaration - defined here and used outside this module 131 ----------------------------------------------------------------------------*/ 132 /* 133 * sin(pi/36*(k+0.5)),k=0..35 134 */ 135 136 const int32 normal_win[36] = 137 { 138 Qfmt_31(0.08723877473068f), Qfmt_31(0.26105238444010f), Qfmt_31(0.43287922787620f), 139 Qfmt_31(0.60141159900854f), Qfmt_31(0.76536686473018f), Qfmt_31(0.92349722647006f), 140 Qfmt_31(0.53729960834682f), Qfmt_31(0.60876142900872f), Qfmt_31(0.67559020761566f), 141 Qfmt_31(-0.73727733681012f), Qfmt_31(-0.79335334029124f), Qfmt_31(0.84339144581289f), 142 Qfmt_31(0.88701083317822f), Qfmt_31(0.92387953251129f), Qfmt_31(-0.95371695074823f), 143 Qfmt_31(-0.97629600711993f), Qfmt_31(-0.99144486137381f), Qfmt_31(-0.99904822158186f), 144 Qfmt_31(0.99904822158186f), Qfmt_31(0.99144486137381f), Qfmt_31(0.97629600711993f), 145 Qfmt_31(0.95371695074823f), Qfmt_31(0.92387953251129f), Qfmt_31(0.88701083317822f), 146 Qfmt_31(0.84339144581289f), Qfmt_31(0.79335334029124f), Qfmt_31(0.73727733681012f), 147 Qfmt_31(0.67559020761566f), Qfmt_31(0.60876142900872f), Qfmt_31(0.53729960834682f), 148 Qfmt_31(0.46174861323503f), Qfmt_31(0.38268343236509f), Qfmt_31(0.30070579950427f), 149 Qfmt_31(0.21643961393810f), Qfmt_31(0.13052619222005f), Qfmt_31(0.04361938736534f) 150 }; 151 152 153 const int32 start_win[36] = 154 { 155 /* k=0..17 sin(pi/36*(k+0.5)), */ 156 Qfmt_31(0.08723877473068f), Qfmt_31(0.26105238444010f), Qfmt_31(0.43287922787620f), 157 Qfmt_31(0.60141159900854f), Qfmt_31(0.76536686473018f), Qfmt_31(0.92349722647006f), 158 Qfmt_31(0.53729960834682f), Qfmt_31(0.60876142900872f), Qfmt_31(0.67559020761566f), 159 Qfmt_31(-0.73727733681012f), Qfmt_31(-0.79335334029124f), Qfmt_31(0.84339144581289f), 160 Qfmt_31(0.88701083317822f), Qfmt_31(0.92387953251129f), Qfmt_31(-0.95371695074823f), 161 Qfmt_31(-0.97629600711993f), Qfmt_31(-0.99144486137381f), Qfmt_31(-0.99904822158186f), 162 163 Qfmt_31(0.99999990000000f), Qfmt_31(0.99999990000000f), Qfmt_31(0.99999990000000f), 164 Qfmt_31(0.99999990000000f), Qfmt_31(0.99999990000000f), Qfmt_31(0.99999990000000f), 165 /* k=24..29; sin(pi/12*(k-18+0.5)) */ 166 Qfmt_31(0.99144486137381f), Qfmt_31(0.92387953251129f), Qfmt_31(0.79335334029124f), 167 Qfmt_31(0.60876142900872f), Qfmt_31(0.38268343236509f), Qfmt_31(0.13052619222005f), 168 169 Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f), 170 Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f) 171 }; 172 173 174 const int32 stop_win[36] = 175 { 176 Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f), 177 Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f), Qfmt_31(0.00000000000000f), 178 /* k=6..11; sin(pi/12*(k-6+0.5)) */ 179 Qfmt_31(0.13052619222005f), Qfmt_31(0.38268343236509f), Qfmt_31(0.60876142900872f), 180 Qfmt_31(-0.79335334029124f), Qfmt_31(-0.92387953251129f), Qfmt_31(0.99144486137381f), 181 182 Qfmt_31(0.99999990000000f), Qfmt_31(0.99999990000000f), Qfmt_31(-0.99999990000000f), 183 Qfmt_31(-0.99999990000000f), Qfmt_31(-0.99999990000000f), Qfmt_31(-0.99999990000000f), 184 /* k=18..35 sin(pi/36*(k+0.5)), */ 185 Qfmt_31(0.99904822158186f), Qfmt_31(0.99144486137381f), Qfmt_31(0.97629600711993f), 186 Qfmt_31(0.95371695074823f), Qfmt_31(0.92387953251129f), Qfmt_31(0.88701083317822f), 187 Qfmt_31(0.84339144581289f), Qfmt_31(0.79335334029124f), Qfmt_31(0.73727733681012f), 188 Qfmt_31(0.67559020761566f), Qfmt_31(0.60876142900872f), Qfmt_31(0.53729960834682f), 189 Qfmt_31(0.46174861323503f), Qfmt_31(0.38268343236509f), Qfmt_31(0.30070579950427f), 190 Qfmt_31(0.21643961393810f), Qfmt_31(0.13052619222005f), Qfmt_31(0.04361938736534f) 191 }; 192 193 194 const int32 short_win[12] = 195 { 196 /* k=0..11; sin(pi/12*(k+0.5)) */ 197 Qfmt_31(0.13052619222005f), Qfmt_31(0.38268343236509f), Qfmt_31(0.60876142900872f), 198 Qfmt_31(0.79335334029124f), Qfmt_31(0.92387953251129f), Qfmt_31(0.99144486137381f), 199 Qfmt_31(0.99144486137381f), Qfmt_31(0.92387953251129f), Qfmt_31(0.79335334029124f), 200 Qfmt_31(0.60876142900872f), Qfmt_31(0.38268343236509f), Qfmt_31(0.13052619222005f), 201 }; 202 /*---------------------------------------------------------------------------- 203 ; EXTERNAL FUNCTION REFERENCES 204 ; Declare functions defined elsewhere and referenced in this module 205 ----------------------------------------------------------------------------*/ 206 207 /*---------------------------------------------------------------------------- 208 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES 209 ; Declare variables used in this module but defined elsewhere 210 ----------------------------------------------------------------------------*/ 211 212 /*---------------------------------------------------------------------------- 213 ; FUNCTION CODE 214 ----------------------------------------------------------------------------*/ 215 216 void pvmp3_imdct_synth(int32 in[SUBBANDS_NUMBER*FILTERBANK_BANDS], 217 int32 overlap[SUBBANDS_NUMBER*FILTERBANK_BANDS], 218 uint32 blk_type, 219 int16 mx_band, 220 int32 used_freq_lines, 221 int32 *Scratch_mem) 222 { 223 224 int32 band; 225 int32 bands2process = used_freq_lines + 2; 226 227 if (bands2process > SUBBANDS_NUMBER) 228 { 229 bands2process = SUBBANDS_NUMBER; /* default */ 230 } 231 232 233 /* 234 * in case of mx_poly_band> 0, do 235 * long transforms 236 */ 237 238 239 for (band = 0; band < bands2process; band++) 240 { 241 uint32 current_blk_type = (band < mx_band) ? LONG : blk_type; 242 243 int32 * out = in + (band * FILTERBANK_BANDS); 244 int32 * history = overlap + (band * FILTERBANK_BANDS); 245 246 switch (current_blk_type) 247 { 248 case LONG: 249 250 pvmp3_mdct_18(out, history, normal_win); 251 252 break; 253 254 case START: 255 256 pvmp3_mdct_18(out, history, start_win); 257 258 break; 259 260 case STOP: 261 262 pvmp3_mdct_18(out, history, stop_win); 263 264 break; 265 266 case SHORT: 267 { 268 int32 *tmp_prev_ovr = &Scratch_mem[FILTERBANK_BANDS]; 269 int32 i; 270 271 for (i = 0; i < 6; i++) 272 { 273 Scratch_mem[i ] = out[(i*3)]; 274 Scratch_mem[6 +i] = out[(i*3) + 1]; 275 Scratch_mem[12 +i] = out[(i*3) + 2]; 276 } 277 278 pvmp3_mdct_6(&Scratch_mem[ 0], &tmp_prev_ovr[ 0]); 279 pvmp3_mdct_6(&Scratch_mem[ 6], &tmp_prev_ovr[ 6]); 280 pvmp3_mdct_6(&Scratch_mem[12], &tmp_prev_ovr[12]); 281 282 for (i = 0; i < 6; i++) 283 { 284 int32 temp = history[i]; 285 /* next iteration overlap */ 286 history[i] = fxp_mul32_Q32(tmp_prev_ovr[ 6+i] << 1, short_win[6+i]); 287 history[i] += fxp_mul32_Q32(Scratch_mem[12+i] << 1, short_win[ i]); 288 out[i] = temp; 289 } 290 291 for (i = 0; i < 6; i++) 292 { 293 out[i+6] = fxp_mul32_Q32(Scratch_mem[i] << 1, short_win[i]); 294 out[i+6] += history[i+6]; 295 /* next iteration overlap */ 296 history[i+6] = fxp_mul32_Q32(tmp_prev_ovr[12+i] << 1, short_win[6+i]); 297 298 } 299 for (i = 0; i < 6; i++) 300 { 301 out[i+12] = fxp_mul32_Q32(tmp_prev_ovr[ i] << 1, short_win[6+i]); 302 out[i+12] += fxp_mul32_Q32(Scratch_mem[6+i] << 1, short_win[ i]); 303 out[i+12] += history[i+12]; 304 history[12+i] = 0; 305 } 306 } 307 308 break; 309 } 310 311 /* 312 * Compensation for frequency inversion of polyphase filterbank 313 * every odd time sample of every odd odd subband is mulitplied by -1 before 314 * processing by the polyphase filter 315 */ 316 317 if (band & 1) 318 { 319 for (int32 slot = 1; slot < FILTERBANK_BANDS; slot += 6) 320 { 321 int32 temp1 = out[slot ]; 322 int32 temp2 = out[slot+2]; 323 int32 temp3 = out[slot+4]; 324 out[slot ] = -temp1; 325 out[slot+2] = -temp2; 326 out[slot+4] = -temp3; 327 } 328 } 329 } 330 331 332 for (band = bands2process; band < SUBBANDS_NUMBER; band++) 333 { 334 int32 * out = in + (band * FILTERBANK_BANDS); 335 int32 * history = overlap + (band * FILTERBANK_BANDS); 336 int32 slot; 337 338 if (band & 1) 339 { 340 for (slot = 0; slot < FILTERBANK_BANDS; slot += 6) 341 { 342 int32 temp1 = history[slot ]; 343 int32 temp2 = history[slot+1]; 344 int32 temp3 = history[slot+2]; 345 out[slot ] = temp1; 346 out[slot+1] = -temp2; 347 out[slot+2] = temp3; 348 349 temp1 = history[slot+3]; 350 temp2 = history[slot+4]; 351 temp3 = history[slot+5]; 352 out[slot+3] = -temp1; 353 out[slot+4] = temp2; 354 out[slot+5] = -temp3; 355 } 356 } 357 else 358 { 359 for (slot = 0; slot < FILTERBANK_BANDS; slot += 3) 360 { 361 int32 temp1 = history[slot ]; 362 int32 temp2 = history[slot+1]; 363 int32 temp3 = history[slot+2]; 364 out[slot ] = temp1; 365 out[slot+1] = temp2; 366 out[slot+2] = temp3; 367 } 368 } 369 370 pv_memset(history, 0, FILTERBANK_BANDS*sizeof(*overlap)); 371 } 372 } 373 374 375 376 377
