1 2 /* ----------------------------------------------------------------------------------------------------------- 3 Software License for The Fraunhofer FDK AAC Codec Library for Android 4 5 Copyright 1995 - 2012 Fraunhofer-Gesellschaft zur Frderung der angewandten Forschung e.V. 6 All rights reserved. 7 8 1. INTRODUCTION 9 The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements 10 the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio. 11 This FDK AAC Codec software is intended to be used on a wide variety of Android devices. 12 13 AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual 14 audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by 15 independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part 16 of the MPEG specifications. 17 18 Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer) 19 may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners 20 individually for the purpose of encoding or decoding bit streams in products that are compliant with 21 the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license 22 these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec 23 software may already be covered under those patent licenses when it is used for those licensed purposes only. 24 25 Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality, 26 are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional 27 applications information and documentation. 28 29 2. COPYRIGHT LICENSE 30 31 Redistribution and use in source and binary forms, with or without modification, are permitted without 32 payment of copyright license fees provided that you satisfy the following conditions: 33 34 You must retain the complete text of this software license in redistributions of the FDK AAC Codec or 35 your modifications thereto in source code form. 36 37 You must retain the complete text of this software license in the documentation and/or other materials 38 provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form. 39 You must make available free of charge copies of the complete source code of the FDK AAC Codec and your 40 modifications thereto to recipients of copies in binary form. 41 42 The name of Fraunhofer may not be used to endorse or promote products derived from this library without 43 prior written permission. 44 45 You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec 46 software or your modifications thereto. 47 48 Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software 49 and the date of any change. For modified versions of the FDK AAC Codec, the term 50 "Fraunhofer FDK AAC Codec Library for Android" must be replaced by the term 51 "Third-Party Modified Version of the Fraunhofer FDK AAC Codec Library for Android." 52 53 3. NO PATENT LICENSE 54 55 NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer, 56 ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with 57 respect to this software. 58 59 You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized 60 by appropriate patent licenses. 61 62 4. DISCLAIMER 63 64 This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright holders and contributors 65 "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, including but not limited to the implied warranties 66 of merchantability and fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 67 CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages, 68 including but not limited to procurement of substitute goods or services; loss of use, data, or profits, 69 or business interruption, however caused and on any theory of liability, whether in contract, strict 70 liability, or tort (including negligence), arising in any way out of the use of this software, even if 71 advised of the possibility of such damage. 72 73 5. CONTACT INFORMATION 74 75 Fraunhofer Institute for Integrated Circuits IIS 76 Attention: Audio and Multimedia Departments - FDK AAC LL 77 Am Wolfsmantel 33 78 91058 Erlangen, Germany 79 80 www.iis.fraunhofer.de/amm 81 amm-info (at) iis.fraunhofer.de 82 ----------------------------------------------------------------------------------------------------------- */ 83 84 /***************************** MPEG-4 AAC Encoder ************************** 85 86 Author(s): M. Werner 87 Description: Block switching 88 89 ******************************************************************************/ 90 91 /****************** Includes *****************************/ 92 93 #include "block_switch.h" 94 #include "genericStds.h" 95 96 97 #define LOWOV_WINDOW _LOWOV_WINDOW 98 99 /**************** internal function prototypes ***********/ 100 101 static FIXP_DBL FDKaacEnc_GetWindowEnergy(const FIXP_DBL in[], const INT blSwWndIdx); 102 103 static void FDKaacEnc_CalcWindowEnergy( BLOCK_SWITCHING_CONTROL *RESTRICT blockSwitchingControl, 104 INT windowLen); 105 106 107 /****************** Constants *****************************/ 108 /* LONG START SHORT STOP LOWOV */ 109 static const INT blockType2windowShape[2][5] = { {SINE_WINDOW, KBD_WINDOW, WRONG_WINDOW, SINE_WINDOW, KBD_WINDOW}, /* LD */ 110 {KBD_WINDOW, SINE_WINDOW, SINE_WINDOW, KBD_WINDOW, WRONG_WINDOW} }; /* LC */ 111 112 /* IIR high pass coeffs */ 113 114 #ifndef SINETABLE_16BIT 115 116 static const FIXP_DBL hiPassCoeff[BLOCK_SWITCHING_IIR_LEN]= 117 { 118 FL2FXCONST_DBL(-0.5095),FL2FXCONST_DBL(0.7548) 119 }; 120 121 static const FIXP_DBL accWindowNrgFac = FL2FXCONST_DBL(0.3f); /* factor for accumulating filtered window energies */ 122 static const FIXP_DBL oneMinusAccWindowNrgFac = FL2FXCONST_DBL(0.7f); 123 /* static const float attackRatio = 10.0; */ /* lower ratio limit for attacks */ 124 static const FIXP_DBL invAttackRatio = FL2FXCONST_DBL(0.1f); /* inverted lower ratio limit for attacks */ 125 126 /* The next constants are scaled, because they are used for comparison with scaled values*/ 127 /* minimum energy for attacks */ 128 static const FIXP_DBL minAttackNrg = (FL2FXCONST_DBL(1e+6f*NORM_PCM_ENERGY)>>BLOCK_SWITCH_ENERGY_SHIFT); /* minimum energy for attacks */ 129 130 #else 131 132 static const FIXP_SGL hiPassCoeff[BLOCK_SWITCHING_IIR_LEN]= 133 { 134 FL2FXCONST_SGL(-0.5095),FL2FXCONST_SGL(0.7548) 135 }; 136 137 static const FIXP_DBL accWindowNrgFac = FL2FXCONST_DBL(0.3f); /* factor for accumulating filtered window energies */ 138 static const FIXP_SGL oneMinusAccWindowNrgFac = FL2FXCONST_SGL(0.7f); 139 /* static const float attackRatio = 10.0; */ /* lower ratio limit for attacks */ 140 static const FIXP_SGL invAttackRatio = FL2FXCONST_SGL(0.1f); /* inverted lower ratio limit for attacks */ 141 /* minimum energy for attacks */ 142 static const FIXP_DBL minAttackNrg = (FL2FXCONST_DBL(1e+6f*NORM_PCM_ENERGY)>>BLOCK_SWITCH_ENERGY_SHIFT); /* minimum energy for attacks */ 143 144 #endif 145 146 /**************** internal function prototypes ***********/ 147 148 static INT FDKaacEnc_GetWindowIndex(INT blockSwWindowIndex); 149 150 static FIXP_DBL FDKaacEnc_GetWindowEnergy(const FIXP_DBL in[], const INT shortWndIdx); 151 152 static void FDKaacEnc_CalcWindowEnergy( BLOCK_SWITCHING_CONTROL *RESTRICT blockSwitchingControl, 153 INT windowLen); 154 155 156 157 /****************** Routines ****************************/ 158 void FDKaacEnc_InitBlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, INT isLowDelay) 159 { 160 /* note: the pointer to timeSignal can be zeroed here, because it is initialized for every call 161 to FDKaacEnc_BlockSwitching anew */ 162 FDKmemclear (blockSwitchingControl, sizeof(BLOCK_SWITCHING_CONTROL)); 163 164 if (isLowDelay) 165 { 166 blockSwitchingControl->nBlockSwitchWindows = 4; 167 blockSwitchingControl->allowShortFrames = 0; 168 blockSwitchingControl->allowLookAhead = 0; 169 } 170 else 171 { 172 blockSwitchingControl->nBlockSwitchWindows = 8; 173 blockSwitchingControl->allowShortFrames = 1; 174 blockSwitchingControl->allowLookAhead = 1; 175 } 176 177 blockSwitchingControl->noOfGroups = MAX_NO_OF_GROUPS; 178 179 /* Initialize startvalue for blocktype */ 180 blockSwitchingControl->lastWindowSequence = LONG_WINDOW; 181 blockSwitchingControl->windowShape = blockType2windowShape[blockSwitchingControl->allowShortFrames][blockSwitchingControl->lastWindowSequence]; 182 183 } 184 185 static const INT suggestedGroupingTable[TRANS_FAC][MAX_NO_OF_GROUPS] = 186 { 187 /* Attack in Window 0 */ {1, 3, 3, 1}, 188 /* Attack in Window 1 */ {1, 1, 3, 3}, 189 /* Attack in Window 2 */ {2, 1, 3, 2}, 190 /* Attack in Window 3 */ {3, 1, 3, 1}, 191 /* Attack in Window 4 */ {3, 1, 1, 3}, 192 /* Attack in Window 5 */ {3, 2, 1, 2}, 193 /* Attack in Window 6 */ {3, 3, 1, 1}, 194 /* Attack in Window 7 */ {3, 3, 1, 1} 195 }; 196 197 /* change block type depending on current blocktype and whether there's an attack */ 198 /* assume no look-ahead */ 199 static const INT chgWndSq[2][N_BLOCKTYPES] = 200 { 201 /* LONG WINDOW START_WINDOW SHORT_WINDOW STOP_WINDOW, LOWOV_WINDOW, WRONG_WINDOW */ 202 /*no attack*/ {LONG_WINDOW, STOP_WINDOW, WRONG_WINDOW, LONG_WINDOW, STOP_WINDOW , WRONG_WINDOW }, 203 /*attack */ {START_WINDOW, LOWOV_WINDOW, WRONG_WINDOW, START_WINDOW, LOWOV_WINDOW, WRONG_WINDOW } 204 }; 205 206 /* change block type depending on current blocktype and whether there's an attack */ 207 /* assume look-ahead */ 208 static const INT chgWndSqLkAhd[2][2][N_BLOCKTYPES] = 209 { 210 /*attack LONG WINDOW START_WINDOW SHORT_WINDOW STOP_WINDOW LOWOV_WINDOW, WRONG_WINDOW */ /* last attack */ 211 /*no attack*/ { {LONG_WINDOW, SHORT_WINDOW, STOP_WINDOW, LONG_WINDOW, WRONG_WINDOW, WRONG_WINDOW}, /* no attack */ 212 /*attack */ {START_WINDOW, SHORT_WINDOW, SHORT_WINDOW, START_WINDOW, WRONG_WINDOW, WRONG_WINDOW} }, /* no attack */ 213 /*no attack*/ { {LONG_WINDOW, SHORT_WINDOW, SHORT_WINDOW, LONG_WINDOW, WRONG_WINDOW, WRONG_WINDOW}, /* attack */ 214 /*attack */ {START_WINDOW, SHORT_WINDOW, SHORT_WINDOW, START_WINDOW, WRONG_WINDOW, WRONG_WINDOW} } /* attack */ 215 }; 216 217 int FDKaacEnc_BlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, const INT granuleLength, const int isLFE) 218 { 219 UINT i; 220 FIXP_DBL enM1, enMax; 221 222 UINT nBlockSwitchWindows = blockSwitchingControl->nBlockSwitchWindows; 223 224 /* for LFE : only LONG window allowed */ 225 if (isLFE) { 226 227 /* case LFE: */ 228 /* only long blocks, always use sine windows (MPEG2 AAC, MPEG4 AAC) */ 229 blockSwitchingControl->lastWindowSequence = LONG_WINDOW; 230 blockSwitchingControl->windowShape = SINE_WINDOW; 231 blockSwitchingControl->noOfGroups = 1; 232 blockSwitchingControl->groupLen[0] = 1; 233 234 return(0); 235 }; 236 237 /* Save current attack index as last attack index */ 238 blockSwitchingControl->lastattack = blockSwitchingControl->attack; 239 blockSwitchingControl->lastAttackIndex = blockSwitchingControl->attackIndex; 240 241 /* Save current window energy as last window energy */ 242 FDKmemcpy(blockSwitchingControl->windowNrg[0], blockSwitchingControl->windowNrg[1], sizeof(blockSwitchingControl->windowNrg[0])); 243 FDKmemcpy(blockSwitchingControl->windowNrgF[0], blockSwitchingControl->windowNrgF[1], sizeof(blockSwitchingControl->windowNrgF[0])); 244 245 if (blockSwitchingControl->allowShortFrames) 246 { 247 /* Calculate suggested grouping info for the last frame */ 248 249 /* Reset grouping info */ 250 FDKmemclear (blockSwitchingControl->groupLen, sizeof(blockSwitchingControl->groupLen)); 251 252 /* Set grouping info */ 253 blockSwitchingControl->noOfGroups = MAX_NO_OF_GROUPS; 254 255 FDKmemcpy(blockSwitchingControl->groupLen, suggestedGroupingTable[blockSwitchingControl->lastAttackIndex], sizeof(blockSwitchingControl->groupLen)); 256 257 if (blockSwitchingControl->attack == TRUE) 258 blockSwitchingControl->maxWindowNrg = FDKaacEnc_GetWindowEnergy(blockSwitchingControl->windowNrg[0], blockSwitchingControl->lastAttackIndex); 259 else 260 blockSwitchingControl->maxWindowNrg = FL2FXCONST_DBL(0.0); 261 262 } 263 264 265 /* Calculate unfiltered and filtered energies in subwindows and combine to segments */ 266 FDKaacEnc_CalcWindowEnergy(blockSwitchingControl, granuleLength>>(nBlockSwitchWindows==4? 2:3 )); 267 268 /* now calculate if there is an attack */ 269 270 /* reset attack */ 271 blockSwitchingControl->attack = FALSE; 272 273 /* look for attack */ 274 enMax = FL2FXCONST_DBL(0.0f); 275 enM1 = blockSwitchingControl->windowNrgF[0][nBlockSwitchWindows-1]; 276 277 for (i=0; i<nBlockSwitchWindows; i++) { 278 FIXP_DBL tmp = fMultDiv2(oneMinusAccWindowNrgFac, blockSwitchingControl->accWindowNrg); 279 blockSwitchingControl->accWindowNrg = fMultAdd(tmp, accWindowNrgFac, enM1) ; 280 281 if (fMult(blockSwitchingControl->windowNrgF[1][i],invAttackRatio) > blockSwitchingControl->accWindowNrg ) { 282 blockSwitchingControl->attack = TRUE; 283 blockSwitchingControl->attackIndex = i; 284 } 285 enM1 = blockSwitchingControl->windowNrgF[1][i]; 286 enMax = fixMax(enMax, enM1); 287 } 288 289 290 if (enMax < minAttackNrg) blockSwitchingControl->attack = FALSE; 291 292 /* Check if attack spreads over frame border */ 293 if((blockSwitchingControl->attack == FALSE) && (blockSwitchingControl->lastattack == TRUE)) { 294 /* if attack is in last window repeat SHORT_WINDOW */ 295 if ( ((blockSwitchingControl->windowNrgF[0][nBlockSwitchWindows-1]>>4) > fMult((FIXP_DBL)(10<<(DFRACT_BITS-1-4)), blockSwitchingControl->windowNrgF[1][1])) 296 && (blockSwitchingControl->lastAttackIndex == (INT)nBlockSwitchWindows-1) 297 ) 298 { 299 blockSwitchingControl->attack = TRUE; 300 blockSwitchingControl->attackIndex = 0; 301 } 302 } 303 304 305 if(blockSwitchingControl->allowLookAhead) 306 { 307 308 309 blockSwitchingControl->lastWindowSequence = 310 chgWndSqLkAhd[blockSwitchingControl->lastattack][blockSwitchingControl->attack][blockSwitchingControl->lastWindowSequence]; 311 } 312 else 313 { 314 /* Low Delay */ 315 blockSwitchingControl->lastWindowSequence = 316 chgWndSq[blockSwitchingControl->attack][blockSwitchingControl->lastWindowSequence]; 317 } 318 319 320 /* update window shape */ 321 blockSwitchingControl->windowShape = blockType2windowShape[blockSwitchingControl->allowShortFrames][blockSwitchingControl->lastWindowSequence]; 322 323 return(0); 324 } 325 326 327 328 static FIXP_DBL FDKaacEnc_GetWindowEnergy(const FIXP_DBL in[], const INT blSwWndIdx) 329 { 330 /* For coherency, change FDKaacEnc_GetWindowEnergy() to calcluate the energy for a block switching analysis windows, 331 not for a short block. The same is done FDKaacEnc_CalcWindowEnergy(). The result of FDKaacEnc_GetWindowEnergy() 332 is used for a comparision of the max energy of left/right channel. */ 333 334 return in[blSwWndIdx]; 335 336 } 337 338 339 static void FDKaacEnc_CalcWindowEnergy(BLOCK_SWITCHING_CONTROL *RESTRICT blockSwitchingControl, INT windowLen) 340 { 341 INT i; 342 UINT w; 343 344 FIXP_SGL hiPassCoeff0 = hiPassCoeff[0]; 345 FIXP_SGL hiPassCoeff1 = hiPassCoeff[1]; 346 347 INT_PCM *timeSignal = blockSwitchingControl->timeSignal; 348 349 /* sum up scalarproduct of timesignal as windowed Energies */ 350 for (w=0; w < blockSwitchingControl->nBlockSwitchWindows; w++) { 351 352 FIXP_DBL temp_windowNrg = FL2FXCONST_DBL(0.0f); 353 FIXP_DBL temp_windowNrgF = FL2FXCONST_DBL(0.0f); 354 FIXP_DBL temp_iirState0 = blockSwitchingControl->iirStates[0]; 355 FIXP_DBL temp_iirState1 = blockSwitchingControl->iirStates[1]; 356 357 /* windowNrg = sum(timesample^2) */ 358 for(i=0;i<windowLen;i++) 359 { 360 361 FIXP_DBL tempUnfiltered, tempFiltred, t1, t2; 362 /* tempUnfiltered is scaled with 1 to prevent overflows during calculation of tempFiltred */ 363 #if SAMPLE_BITS == DFRACT_BITS 364 tempUnfiltered = (FIXP_DBL) *timeSignal++ >> 1; 365 #else 366 tempUnfiltered = (FIXP_DBL) *timeSignal++ << (DFRACT_BITS-SAMPLE_BITS-1); 367 #endif 368 t1 = fMultDiv2(hiPassCoeff1, tempUnfiltered-temp_iirState0); 369 t2 = fMultDiv2(hiPassCoeff0, temp_iirState1); 370 tempFiltred = (t1 - t2) << 1; 371 372 temp_iirState0 = tempUnfiltered; 373 temp_iirState1 = tempFiltred; 374 375 /* subtract 2 from overallscaling (BLOCK_SWITCH_ENERGY_SHIFT) 376 * because tempUnfiltered was already scaled with 1 (is 2 after squaring) 377 * subtract 1 from overallscaling (BLOCK_SWITCH_ENERGY_SHIFT) 378 * because of fMultDiv2 is doing a scaling by one */ 379 temp_windowNrg += fPow2Div2(tempUnfiltered) >> (BLOCK_SWITCH_ENERGY_SHIFT - 1 - 2); 380 temp_windowNrgF += fPow2Div2(tempFiltred) >> (BLOCK_SWITCH_ENERGY_SHIFT - 1 - 2); 381 } 382 blockSwitchingControl->windowNrg[1][w] = temp_windowNrg; 383 blockSwitchingControl->windowNrgF[1][w] = temp_windowNrgF; 384 blockSwitchingControl->iirStates[0] = temp_iirState0; 385 blockSwitchingControl->iirStates[1] = temp_iirState1; 386 } 387 } 388 389 390 static const UCHAR synchronizedBlockTypeTable[5][5] = 391 { 392 /* LONG_WINDOW START_WINDOW SHORT_WINDOW STOP_WINDOW LOWOV_WINDOW*/ 393 /* LONG_WINDOW */ {LONG_WINDOW, START_WINDOW, SHORT_WINDOW, STOP_WINDOW, LOWOV_WINDOW}, 394 /* START_WINDOW */ {START_WINDOW, START_WINDOW, SHORT_WINDOW, SHORT_WINDOW, LOWOV_WINDOW}, 395 /* SHORT_WINDOW */ {SHORT_WINDOW, SHORT_WINDOW, SHORT_WINDOW, SHORT_WINDOW, WRONG_WINDOW}, 396 /* STOP_WINDOW */ {STOP_WINDOW, SHORT_WINDOW, SHORT_WINDOW, STOP_WINDOW, LOWOV_WINDOW}, 397 /* LOWOV_WINDOW */ {LOWOV_WINDOW, LOWOV_WINDOW, WRONG_WINDOW, LOWOV_WINDOW, LOWOV_WINDOW}, 398 }; 399 400 int FDKaacEnc_SyncBlockSwitching ( 401 BLOCK_SWITCHING_CONTROL *blockSwitchingControlLeft, 402 BLOCK_SWITCHING_CONTROL *blockSwitchingControlRight, 403 const INT nChannels, 404 const INT commonWindow ) 405 { 406 UCHAR patchType = LONG_WINDOW; 407 408 if( nChannels == 2 && commonWindow == TRUE) 409 { 410 /* could be better with a channel loop (need a handle to psy_data) */ 411 /* get suggested Block Types and synchronize */ 412 patchType = synchronizedBlockTypeTable[patchType][blockSwitchingControlLeft->lastWindowSequence]; 413 patchType = synchronizedBlockTypeTable[patchType][blockSwitchingControlRight->lastWindowSequence]; 414 415 /* sanity check (no change from low overlap window to short winow and vice versa) */ 416 if (patchType == WRONG_WINDOW) 417 return -1; /* mixed up AAC-LC and AAC-LD */ 418 419 /* Set synchronized Blocktype */ 420 blockSwitchingControlLeft->lastWindowSequence = patchType; 421 blockSwitchingControlRight->lastWindowSequence = patchType; 422 423 /* update window shape */ 424 blockSwitchingControlLeft->windowShape = blockType2windowShape[blockSwitchingControlLeft->allowShortFrames][blockSwitchingControlLeft->lastWindowSequence]; 425 blockSwitchingControlRight->windowShape = blockType2windowShape[blockSwitchingControlLeft->allowShortFrames][blockSwitchingControlRight->lastWindowSequence]; 426 } 427 428 if (blockSwitchingControlLeft->allowShortFrames) 429 { 430 int i; 431 432 if( nChannels == 2 ) 433 { 434 if (commonWindow == TRUE) 435 { 436 /* Synchronize grouping info */ 437 int windowSequenceLeftOld = blockSwitchingControlLeft->lastWindowSequence; 438 int windowSequenceRightOld = blockSwitchingControlRight->lastWindowSequence; 439 440 /* Long Blocks */ 441 if(patchType != SHORT_WINDOW) { 442 /* Set grouping info */ 443 blockSwitchingControlLeft->noOfGroups = 1; 444 blockSwitchingControlRight->noOfGroups = 1; 445 blockSwitchingControlLeft->groupLen[0] = 1; 446 blockSwitchingControlRight->groupLen[0] = 1; 447 448 for (i = 1; i < MAX_NO_OF_GROUPS; i++) 449 { 450 blockSwitchingControlLeft->groupLen[i] = 0; 451 blockSwitchingControlRight->groupLen[i] = 0; 452 } 453 } 454 455 /* Short Blocks */ 456 else { 457 /* in case all two channels were detected as short-blocks before syncing, use the grouping of channel with higher maxWindowNrg */ 458 if( (windowSequenceLeftOld == SHORT_WINDOW) && 459 (windowSequenceRightOld == SHORT_WINDOW) ) 460 { 461 if(blockSwitchingControlLeft->maxWindowNrg > blockSwitchingControlRight->maxWindowNrg) { 462 /* Left Channel wins */ 463 blockSwitchingControlRight->noOfGroups = blockSwitchingControlLeft->noOfGroups; 464 for (i = 0; i < MAX_NO_OF_GROUPS; i++){ 465 blockSwitchingControlRight->groupLen[i] = blockSwitchingControlLeft->groupLen[i]; 466 } 467 } 468 else { 469 /* Right Channel wins */ 470 blockSwitchingControlLeft->noOfGroups = blockSwitchingControlRight->noOfGroups; 471 for (i = 0; i < MAX_NO_OF_GROUPS; i++){ 472 blockSwitchingControlLeft->groupLen[i] = blockSwitchingControlRight->groupLen[i]; 473 } 474 } 475 } 476 else if ( (windowSequenceLeftOld == SHORT_WINDOW) && 477 (windowSequenceRightOld != SHORT_WINDOW) ) 478 { 479 /* else use grouping of short-block channel */ 480 blockSwitchingControlRight->noOfGroups = blockSwitchingControlLeft->noOfGroups; 481 for (i = 0; i < MAX_NO_OF_GROUPS; i++){ 482 blockSwitchingControlRight->groupLen[i] = blockSwitchingControlLeft->groupLen[i]; 483 } 484 } 485 else if ( (windowSequenceRightOld == SHORT_WINDOW) && 486 (windowSequenceLeftOld != SHORT_WINDOW) ) 487 { 488 blockSwitchingControlLeft->noOfGroups = blockSwitchingControlRight->noOfGroups; 489 for (i = 0; i < MAX_NO_OF_GROUPS; i++){ 490 blockSwitchingControlLeft->groupLen[i] = blockSwitchingControlRight->groupLen[i]; 491 } 492 } else { 493 /* syncing a start and stop window ... */ 494 blockSwitchingControlLeft->noOfGroups = blockSwitchingControlRight->noOfGroups = 2; 495 blockSwitchingControlLeft->groupLen[0] = blockSwitchingControlRight->groupLen[0] = 4; 496 blockSwitchingControlLeft->groupLen[1] = blockSwitchingControlRight->groupLen[1] = 4; 497 } 498 } /* Short Blocks */ 499 } 500 else { 501 /* stereo, no common window */ 502 if (blockSwitchingControlLeft->lastWindowSequence!=SHORT_WINDOW){ 503 blockSwitchingControlLeft->noOfGroups = 1; 504 blockSwitchingControlLeft->groupLen[0] = 1; 505 for (i = 1; i < MAX_NO_OF_GROUPS; i++) 506 { 507 blockSwitchingControlLeft->groupLen[i] = 0; 508 } 509 } 510 if (blockSwitchingControlRight->lastWindowSequence!=SHORT_WINDOW){ 511 blockSwitchingControlRight->noOfGroups = 1; 512 blockSwitchingControlRight->groupLen[0] = 1; 513 for (i = 1; i < MAX_NO_OF_GROUPS; i++) 514 { 515 blockSwitchingControlRight->groupLen[i] = 0; 516 } 517 } 518 } /* common window */ 519 } else { 520 /* Mono */ 521 if (blockSwitchingControlLeft->lastWindowSequence!=SHORT_WINDOW){ 522 blockSwitchingControlLeft->noOfGroups = 1; 523 blockSwitchingControlLeft->groupLen[0] = 1; 524 525 for (i = 1; i < MAX_NO_OF_GROUPS; i++) 526 { 527 blockSwitchingControlLeft->groupLen[i] = 0; 528 } 529 } 530 } 531 } /* allowShortFrames */ 532 533 534 /* Translate LOWOV_WINDOW block type to a meaningful window shape. */ 535 if ( ! blockSwitchingControlLeft->allowShortFrames ) { 536 if ( blockSwitchingControlLeft->lastWindowSequence != LONG_WINDOW 537 && blockSwitchingControlLeft->lastWindowSequence != STOP_WINDOW ) 538 { 539 blockSwitchingControlLeft->lastWindowSequence = LONG_WINDOW; 540 blockSwitchingControlLeft->windowShape = LOL_WINDOW; 541 } 542 } 543 if (nChannels == 2) { 544 if ( ! blockSwitchingControlRight->allowShortFrames ) { 545 if ( blockSwitchingControlRight->lastWindowSequence != LONG_WINDOW 546 && blockSwitchingControlRight->lastWindowSequence != STOP_WINDOW ) 547 { 548 blockSwitchingControlRight->lastWindowSequence = LONG_WINDOW; 549 blockSwitchingControlRight->windowShape = LOL_WINDOW; 550 } 551 } 552 } 553 554 return 0; 555 } 556 557 558
