1 /* -----------------------------------------------------------------------------
2 Software License for The Fraunhofer FDK AAC Codec Library for Android
3
4 © Copyright 1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten
5 Forschung e.V. All rights reserved.
6
7 1. INTRODUCTION
8 The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software
9 that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding
10 scheme for digital audio. This FDK AAC Codec software is intended to be used on
11 a wide variety of Android devices.
12
13 AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient
14 general perceptual audio codecs. AAC-ELD is considered the best-performing
15 full-bandwidth communications codec by independent studies and is widely
16 deployed. AAC has been standardized by ISO and IEC as part of the MPEG
17 specifications.
18
19 Patent licenses for necessary patent claims for the FDK AAC Codec (including
20 those of Fraunhofer) may be obtained through Via Licensing
21 (www.vialicensing.com) or through the respective patent owners individually for
22 the purpose of encoding or decoding bit streams in products that are compliant
23 with the ISO/IEC MPEG audio standards. Please note that most manufacturers of
24 Android devices already license these patent claims through Via Licensing or
25 directly from the patent owners, and therefore FDK AAC Codec software may
26 already be covered under those patent licenses when it is used for those
27 licensed purposes only.
28
29 Commercially-licensed AAC software libraries, including floating-point versions
30 with enhanced sound quality, are also available from Fraunhofer. Users are
31 encouraged to check the Fraunhofer website for additional applications
32 information and documentation.
33
34 2. COPYRIGHT LICENSE
35
36 Redistribution and use in source and binary forms, with or without modification,
37 are permitted without payment of copyright license fees provided that you
38 satisfy the following conditions:
39
40 You must retain the complete text of this software license in redistributions of
41 the FDK AAC Codec or your modifications thereto in source code form.
42
43 You must retain the complete text of this software license in the documentation
44 and/or other materials provided with redistributions of the FDK AAC Codec or
45 your modifications thereto in binary form. You must make available free of
46 charge copies of the complete source code of the FDK AAC Codec and your
47 modifications thereto to recipients of copies in binary form.
48
49 The name of Fraunhofer may not be used to endorse or promote products derived
50 from this library without prior written permission.
51
52 You may not charge copyright license fees for anyone to use, copy or distribute
53 the FDK AAC Codec software or your modifications thereto.
54
55 Your modified versions of the FDK AAC Codec must carry prominent notices stating
56 that you changed the software and the date of any change. For modified versions
57 of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android"
58 must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK
59 AAC Codec Library for Android."
60
61 3. NO PATENT LICENSE
62
63 NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without
64 limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE.
65 Fraunhofer provides no warranty of patent non-infringement with respect to this
66 software.
67
68 You may use this FDK AAC Codec software or modifications thereto only for
69 purposes that are authorized by appropriate patent licenses.
70
71 4. DISCLAIMER
72
73 This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright
74 holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
75 including but not limited to the implied warranties of merchantability and
76 fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
77 CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary,
78 or consequential damages, including but not limited to procurement of substitute
79 goods or services; loss of use, data, or profits, or business interruption,
80 however caused and on any theory of liability, whether in contract, strict
81 liability, or tort (including negligence), arising in any way out of the use of
82 this software, even if advised of the possibility of such damage.
83
84 5. CONTACT INFORMATION
85
86 Fraunhofer Institute for Integrated Circuits IIS
87 Attention: Audio and Multimedia Departments - FDK AAC LL
88 Am Wolfsmantel 33
89 91058 Erlangen, Germany
90
91 www.iis.fraunhofer.de/amm
92 amm-info@iis.fraunhofer.de
93 ----------------------------------------------------------------------------- */
94
95 /**************************** AAC encoder library ******************************
96
97 Author(s): M. Werner, Tobias Chalupka
98
99 Description: Block switching
100
101 *******************************************************************************/
102
103 /****************** Includes *****************************/
104
105 #include "block_switch.h"
106 #include "genericStds.h"
107
108 #define LOWOV_WINDOW _LOWOV_WINDOW
109
110 /**************** internal function prototypes ***********/
111
112 static FIXP_DBL FDKaacEnc_GetWindowEnergy(const FIXP_DBL in[],
113 const INT blSwWndIdx);
114
115 static void FDKaacEnc_CalcWindowEnergy(
116 BLOCK_SWITCHING_CONTROL *RESTRICT blockSwitchingControl, INT windowLen,
117 const INT_PCM *pTimeSignal);
118
119 /****************** Constants *****************************/
120 /* LONG START
121 * SHORT STOP LOWOV */
122 static const INT blockType2windowShape[2][5] = {
123 {SINE_WINDOW, KBD_WINDOW, WRONG_WINDOW, SINE_WINDOW, KBD_WINDOW}, /* LD */
124 {KBD_WINDOW, SINE_WINDOW, SINE_WINDOW, KBD_WINDOW, WRONG_WINDOW}}; /* LC */
125
126 /* IIR high pass coeffs */
127
128 #ifndef SINETABLE_16BIT
129
130 static const FIXP_DBL hiPassCoeff[BLOCK_SWITCHING_IIR_LEN] = {
131 FL2FXCONST_DBL(-0.5095), FL2FXCONST_DBL(0.7548)};
132
133 static const FIXP_DBL accWindowNrgFac =
134 FL2FXCONST_DBL(0.3f); /* factor for accumulating filtered window energies */
135 static const FIXP_DBL oneMinusAccWindowNrgFac = FL2FXCONST_DBL(0.7f);
136 /* static const float attackRatio = 10.0; */ /* lower ratio limit for attacks */
137 static const FIXP_DBL invAttackRatio =
138 FL2FXCONST_DBL(0.1f); /* inverted lower ratio limit for attacks */
139
140 /* The next constants are scaled, because they are used for comparison with
141 * scaled values*/
142 /* minimum energy for attacks */
143 static const FIXP_DBL minAttackNrg =
144 (FL2FXCONST_DBL(1e+6f * NORM_PCM_ENERGY) >>
145 BLOCK_SWITCH_ENERGY_SHIFT); /* minimum energy for attacks */
146
147 #else
148
149 static const FIXP_SGL hiPassCoeff[BLOCK_SWITCHING_IIR_LEN] = {
150 FL2FXCONST_SGL(-0.5095), FL2FXCONST_SGL(0.7548)};
151
152 static const FIXP_DBL accWindowNrgFac =
153 FL2FXCONST_DBL(0.3f); /* factor for accumulating filtered window energies */
154 static const FIXP_SGL oneMinusAccWindowNrgFac = FL2FXCONST_SGL(0.7f);
155 /* static const float attackRatio = 10.0; */ /* lower ratio limit for attacks */
156 static const FIXP_SGL invAttackRatio =
157 FL2FXCONST_SGL(0.1f); /* inverted lower ratio limit for attacks */
158 /* minimum energy for attacks */
159 static const FIXP_DBL minAttackNrg =
160 (FL2FXCONST_DBL(1e+6f * NORM_PCM_ENERGY) >>
161 BLOCK_SWITCH_ENERGY_SHIFT); /* minimum energy for attacks */
162
163 #endif
164
165 /**************** internal function prototypes ***********/
166
167 /****************** Routines ****************************/
FDKaacEnc_InitBlockSwitching(BLOCK_SWITCHING_CONTROL * blockSwitchingControl,INT isLowDelay)168 void FDKaacEnc_InitBlockSwitching(
169 BLOCK_SWITCHING_CONTROL *blockSwitchingControl, INT isLowDelay) {
170 FDKmemclear(blockSwitchingControl, sizeof(BLOCK_SWITCHING_CONTROL));
171
172 if (isLowDelay) {
173 blockSwitchingControl->nBlockSwitchWindows = 4;
174 blockSwitchingControl->allowShortFrames = 0;
175 blockSwitchingControl->allowLookAhead = 0;
176 } else {
177 blockSwitchingControl->nBlockSwitchWindows = 8;
178 blockSwitchingControl->allowShortFrames = 1;
179 blockSwitchingControl->allowLookAhead = 1;
180 }
181
182 blockSwitchingControl->noOfGroups = MAX_NO_OF_GROUPS;
183
184 /* Initialize startvalue for blocktype */
185 blockSwitchingControl->lastWindowSequence = LONG_WINDOW;
186 blockSwitchingControl->windowShape =
187 blockType2windowShape[blockSwitchingControl->allowShortFrames]
188 [blockSwitchingControl->lastWindowSequence];
189 }
190
191 static const INT suggestedGroupingTable[TRANS_FAC][MAX_NO_OF_GROUPS] = {
192 /* Attack in Window 0 */ {1, 3, 3, 1},
193 /* Attack in Window 1 */ {1, 1, 3, 3},
194 /* Attack in Window 2 */ {2, 1, 3, 2},
195 /* Attack in Window 3 */ {3, 1, 3, 1},
196 /* Attack in Window 4 */ {3, 1, 1, 3},
197 /* Attack in Window 5 */ {3, 2, 1, 2},
198 /* Attack in Window 6 */ {3, 3, 1, 1},
199 /* Attack in Window 7 */ {3, 3, 1, 1}};
200
201 /* change block type depending on current blocktype and whether there's an
202 * attack */
203 /* assume no look-ahead */
204 static const INT chgWndSq[2][N_BLOCKTYPES] = {
205 /* LONG WINDOW START_WINDOW SHORT_WINDOW STOP_WINDOW,
206 LOWOV_WINDOW, WRONG_WINDOW */
207 /*no attack*/ {LONG_WINDOW, STOP_WINDOW, WRONG_WINDOW, LONG_WINDOW,
208 STOP_WINDOW, WRONG_WINDOW},
209 /*attack */ {START_WINDOW, LOWOV_WINDOW, WRONG_WINDOW, START_WINDOW,
210 LOWOV_WINDOW, WRONG_WINDOW}};
211
212 /* change block type depending on current blocktype and whether there's an
213 * attack */
214 /* assume look-ahead */
215 static const INT chgWndSqLkAhd[2][2][N_BLOCKTYPES] = {
216 /*attack LONG WINDOW START_WINDOW SHORT_WINDOW STOP_WINDOW LOWOV_WINDOW, WRONG_WINDOW */ /* last attack */
217 /*no attack*/ {
218 {LONG_WINDOW, SHORT_WINDOW, STOP_WINDOW, LONG_WINDOW, WRONG_WINDOW,
219 WRONG_WINDOW}, /* no attack */
220 /*attack */ {START_WINDOW, SHORT_WINDOW, SHORT_WINDOW, START_WINDOW,
221 WRONG_WINDOW, WRONG_WINDOW}}, /* no attack */
222 /*no attack*/ {{LONG_WINDOW, SHORT_WINDOW, SHORT_WINDOW, LONG_WINDOW,
223 WRONG_WINDOW, WRONG_WINDOW}, /* attack */
224 /*attack */ {START_WINDOW, SHORT_WINDOW, SHORT_WINDOW,
225 START_WINDOW, WRONG_WINDOW,
226 WRONG_WINDOW}} /* attack */
227 };
228
FDKaacEnc_BlockSwitching(BLOCK_SWITCHING_CONTROL * blockSwitchingControl,const INT granuleLength,const int isLFE,const INT_PCM * pTimeSignal)229 int FDKaacEnc_BlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControl,
230 const INT granuleLength, const int isLFE,
231 const INT_PCM *pTimeSignal) {
232 UINT i;
233 FIXP_DBL enM1, enMax;
234
235 UINT nBlockSwitchWindows = blockSwitchingControl->nBlockSwitchWindows;
236
237 /* for LFE : only LONG window allowed */
238 if (isLFE) {
239 /* case LFE: */
240 /* only long blocks, always use sine windows (MPEG2 AAC, MPEG4 AAC) */
241 blockSwitchingControl->lastWindowSequence = LONG_WINDOW;
242 blockSwitchingControl->windowShape = SINE_WINDOW;
243 blockSwitchingControl->noOfGroups = 1;
244 blockSwitchingControl->groupLen[0] = 1;
245
246 return (0);
247 };
248
249 /* Save current attack index as last attack index */
250 blockSwitchingControl->lastattack = blockSwitchingControl->attack;
251 blockSwitchingControl->lastAttackIndex = blockSwitchingControl->attackIndex;
252
253 /* Save current window energy as last window energy */
254 FDKmemcpy(blockSwitchingControl->windowNrg[0],
255 blockSwitchingControl->windowNrg[1],
256 sizeof(blockSwitchingControl->windowNrg[0]));
257 FDKmemcpy(blockSwitchingControl->windowNrgF[0],
258 blockSwitchingControl->windowNrgF[1],
259 sizeof(blockSwitchingControl->windowNrgF[0]));
260
261 if (blockSwitchingControl->allowShortFrames) {
262 /* Calculate suggested grouping info for the last frame */
263
264 /* Reset grouping info */
265 FDKmemclear(blockSwitchingControl->groupLen,
266 sizeof(blockSwitchingControl->groupLen));
267
268 /* Set grouping info */
269 blockSwitchingControl->noOfGroups = MAX_NO_OF_GROUPS;
270
271 FDKmemcpy(blockSwitchingControl->groupLen,
272 suggestedGroupingTable[blockSwitchingControl->lastAttackIndex],
273 sizeof(blockSwitchingControl->groupLen));
274
275 if (blockSwitchingControl->attack == TRUE)
276 blockSwitchingControl->maxWindowNrg =
277 FDKaacEnc_GetWindowEnergy(blockSwitchingControl->windowNrg[0],
278 blockSwitchingControl->lastAttackIndex);
279 else
280 blockSwitchingControl->maxWindowNrg = FL2FXCONST_DBL(0.0);
281 }
282
283 /* Calculate unfiltered and filtered energies in subwindows and combine to
284 * segments */
285 FDKaacEnc_CalcWindowEnergy(
286 blockSwitchingControl,
287 granuleLength >> (nBlockSwitchWindows == 4 ? 2 : 3), pTimeSignal);
288
289 /* now calculate if there is an attack */
290
291 /* reset attack */
292 blockSwitchingControl->attack = FALSE;
293
294 /* look for attack */
295 enMax = FL2FXCONST_DBL(0.0f);
296 enM1 = blockSwitchingControl->windowNrgF[0][nBlockSwitchWindows - 1];
297
298 for (i = 0; i < nBlockSwitchWindows; i++) {
299 FIXP_DBL tmp =
300 fMultDiv2(oneMinusAccWindowNrgFac, blockSwitchingControl->accWindowNrg);
301 blockSwitchingControl->accWindowNrg = fMultAdd(tmp, accWindowNrgFac, enM1);
302
303 if (fMult(blockSwitchingControl->windowNrgF[1][i], invAttackRatio) >
304 blockSwitchingControl->accWindowNrg) {
305 blockSwitchingControl->attack = TRUE;
306 blockSwitchingControl->attackIndex = i;
307 }
308 enM1 = blockSwitchingControl->windowNrgF[1][i];
309 enMax = fixMax(enMax, enM1);
310 }
311
312 if (enMax < minAttackNrg) blockSwitchingControl->attack = FALSE;
313
314 /* Check if attack spreads over frame border */
315 if ((blockSwitchingControl->attack == FALSE) &&
316 (blockSwitchingControl->lastattack == TRUE)) {
317 /* if attack is in last window repeat SHORT_WINDOW */
318 if (((blockSwitchingControl->windowNrgF[0][nBlockSwitchWindows - 1] >> 4) >
319 fMult((FIXP_DBL)(10 << (DFRACT_BITS - 1 - 4)),
320 blockSwitchingControl->windowNrgF[1][1])) &&
321 (blockSwitchingControl->lastAttackIndex ==
322 (INT)nBlockSwitchWindows - 1)) {
323 blockSwitchingControl->attack = TRUE;
324 blockSwitchingControl->attackIndex = 0;
325 }
326 }
327
328 if (blockSwitchingControl->allowLookAhead) {
329 blockSwitchingControl->lastWindowSequence =
330 chgWndSqLkAhd[blockSwitchingControl->lastattack]
331 [blockSwitchingControl->attack]
332 [blockSwitchingControl->lastWindowSequence];
333 } else {
334 /* Low Delay */
335 blockSwitchingControl->lastWindowSequence =
336 chgWndSq[blockSwitchingControl->attack]
337 [blockSwitchingControl->lastWindowSequence];
338 }
339
340 /* update window shape */
341 blockSwitchingControl->windowShape =
342 blockType2windowShape[blockSwitchingControl->allowShortFrames]
343 [blockSwitchingControl->lastWindowSequence];
344
345 return (0);
346 }
347
FDKaacEnc_GetWindowEnergy(const FIXP_DBL in[],const INT blSwWndIdx)348 static FIXP_DBL FDKaacEnc_GetWindowEnergy(const FIXP_DBL in[],
349 const INT blSwWndIdx) {
350 /* For coherency, change FDKaacEnc_GetWindowEnergy() to calcluate the energy
351 for a block switching analysis windows, not for a short block. The same is
352 done FDKaacEnc_CalcWindowEnergy(). The result of
353 FDKaacEnc_GetWindowEnergy() is used for a comparision of the max energy of
354 left/right channel. */
355
356 return in[blSwWndIdx];
357 }
358
FDKaacEnc_CalcWindowEnergy(BLOCK_SWITCHING_CONTROL * RESTRICT blockSwitchingControl,INT windowLen,const INT_PCM * pTimeSignal)359 static void FDKaacEnc_CalcWindowEnergy(
360 BLOCK_SWITCHING_CONTROL *RESTRICT blockSwitchingControl, INT windowLen,
361 const INT_PCM *pTimeSignal) {
362 INT i;
363 UINT w;
364
365 #ifndef SINETABLE_16BIT
366 const FIXP_DBL hiPassCoeff0 = hiPassCoeff[0];
367 const FIXP_DBL hiPassCoeff1 = hiPassCoeff[1];
368 #else
369 const FIXP_SGL hiPassCoeff0 = hiPassCoeff[0];
370 const FIXP_SGL hiPassCoeff1 = hiPassCoeff[1];
371 #endif
372
373 FIXP_DBL temp_iirState0 = blockSwitchingControl->iirStates[0];
374 FIXP_DBL temp_iirState1 = blockSwitchingControl->iirStates[1];
375
376 /* sum up scalarproduct of timesignal as windowed Energies */
377 for (w = 0; w < blockSwitchingControl->nBlockSwitchWindows; w++) {
378 ULONG temp_windowNrg = 0x0;
379 ULONG temp_windowNrgF = 0x0;
380
381 /* windowNrg = sum(timesample^2) */
382 for (i = 0; i < windowLen; i++) {
383 FIXP_DBL tempUnfiltered, t1, t2;
384 /* tempUnfiltered is scaled with 1 to prevent overflows during calculation
385 * of tempFiltred */
386 #if SAMPLE_BITS == DFRACT_BITS
387 tempUnfiltered = (FIXP_DBL)*pTimeSignal++ >> 1;
388 #else
389 tempUnfiltered = (FIXP_DBL)*pTimeSignal++
390 << (DFRACT_BITS - SAMPLE_BITS - 1);
391 #endif
392 t1 = fMultDiv2(hiPassCoeff1, tempUnfiltered - temp_iirState0);
393 t2 = fMultDiv2(hiPassCoeff0, temp_iirState1);
394 temp_iirState0 = tempUnfiltered;
395 temp_iirState1 = (t1 - t2) << 1;
396
397 temp_windowNrg += (LONG)fPow2Div2(temp_iirState0) >>
398 (BLOCK_SWITCH_ENERGY_SHIFT - 1 - 2);
399 temp_windowNrgF += (LONG)fPow2Div2(temp_iirState1) >>
400 (BLOCK_SWITCH_ENERGY_SHIFT - 1 - 2);
401 }
402 blockSwitchingControl->windowNrg[1][w] =
403 (LONG)fMin(temp_windowNrg, (UINT)MAXVAL_DBL);
404 blockSwitchingControl->windowNrgF[1][w] =
405 (LONG)fMin(temp_windowNrgF, (UINT)MAXVAL_DBL);
406 }
407 blockSwitchingControl->iirStates[0] = temp_iirState0;
408 blockSwitchingControl->iirStates[1] = temp_iirState1;
409 }
410
411 static const UCHAR synchronizedBlockTypeTable[5][5] = {
412 /* LONG_WINDOW START_WINDOW SHORT_WINDOW STOP_WINDOW
413 LOWOV_WINDOW*/
414 /* LONG_WINDOW */ {LONG_WINDOW, START_WINDOW, SHORT_WINDOW, STOP_WINDOW,
415 LOWOV_WINDOW},
416 /* START_WINDOW */
417 {START_WINDOW, START_WINDOW, SHORT_WINDOW, SHORT_WINDOW, LOWOV_WINDOW},
418 /* SHORT_WINDOW */
419 {SHORT_WINDOW, SHORT_WINDOW, SHORT_WINDOW, SHORT_WINDOW, WRONG_WINDOW},
420 /* STOP_WINDOW */
421 {STOP_WINDOW, SHORT_WINDOW, SHORT_WINDOW, STOP_WINDOW, LOWOV_WINDOW},
422 /* LOWOV_WINDOW */
423 {LOWOV_WINDOW, LOWOV_WINDOW, WRONG_WINDOW, LOWOV_WINDOW, LOWOV_WINDOW},
424 };
425
FDKaacEnc_SyncBlockSwitching(BLOCK_SWITCHING_CONTROL * blockSwitchingControlLeft,BLOCK_SWITCHING_CONTROL * blockSwitchingControlRight,const INT nChannels,const INT commonWindow)426 int FDKaacEnc_SyncBlockSwitching(
427 BLOCK_SWITCHING_CONTROL *blockSwitchingControlLeft,
428 BLOCK_SWITCHING_CONTROL *blockSwitchingControlRight, const INT nChannels,
429 const INT commonWindow) {
430 UCHAR patchType = LONG_WINDOW;
431
432 if (nChannels == 2 && commonWindow == TRUE) {
433 /* could be better with a channel loop (need a handle to psy_data) */
434 /* get suggested Block Types and synchronize */
435 patchType = synchronizedBlockTypeTable[patchType][blockSwitchingControlLeft
436 ->lastWindowSequence];
437 patchType = synchronizedBlockTypeTable[patchType][blockSwitchingControlRight
438 ->lastWindowSequence];
439
440 /* sanity check (no change from low overlap window to short winow and vice
441 * versa) */
442 if (patchType == WRONG_WINDOW) return -1; /* mixed up AAC-LC and AAC-LD */
443
444 /* Set synchronized Blocktype */
445 blockSwitchingControlLeft->lastWindowSequence = patchType;
446 blockSwitchingControlRight->lastWindowSequence = patchType;
447
448 /* update window shape */
449 blockSwitchingControlLeft->windowShape =
450 blockType2windowShape[blockSwitchingControlLeft->allowShortFrames]
451 [blockSwitchingControlLeft->lastWindowSequence];
452 blockSwitchingControlRight->windowShape =
453 blockType2windowShape[blockSwitchingControlLeft->allowShortFrames]
454 [blockSwitchingControlRight->lastWindowSequence];
455 }
456
457 if (blockSwitchingControlLeft->allowShortFrames) {
458 int i;
459
460 if (nChannels == 2) {
461 if (commonWindow == TRUE) {
462 /* Synchronize grouping info */
463 int windowSequenceLeftOld =
464 blockSwitchingControlLeft->lastWindowSequence;
465 int windowSequenceRightOld =
466 blockSwitchingControlRight->lastWindowSequence;
467
468 /* Long Blocks */
469 if (patchType != SHORT_WINDOW) {
470 /* Set grouping info */
471 blockSwitchingControlLeft->noOfGroups = 1;
472 blockSwitchingControlRight->noOfGroups = 1;
473 blockSwitchingControlLeft->groupLen[0] = 1;
474 blockSwitchingControlRight->groupLen[0] = 1;
475
476 for (i = 1; i < MAX_NO_OF_GROUPS; i++) {
477 blockSwitchingControlLeft->groupLen[i] = 0;
478 blockSwitchingControlRight->groupLen[i] = 0;
479 }
480 }
481
482 /* Short Blocks */
483 else {
484 /* in case all two channels were detected as short-blocks before
485 * syncing, use the grouping of channel with higher maxWindowNrg */
486 if ((windowSequenceLeftOld == SHORT_WINDOW) &&
487 (windowSequenceRightOld == SHORT_WINDOW)) {
488 if (blockSwitchingControlLeft->maxWindowNrg >
489 blockSwitchingControlRight->maxWindowNrg) {
490 /* Left Channel wins */
491 blockSwitchingControlRight->noOfGroups =
492 blockSwitchingControlLeft->noOfGroups;
493 for (i = 0; i < MAX_NO_OF_GROUPS; i++) {
494 blockSwitchingControlRight->groupLen[i] =
495 blockSwitchingControlLeft->groupLen[i];
496 }
497 } else {
498 /* Right Channel wins */
499 blockSwitchingControlLeft->noOfGroups =
500 blockSwitchingControlRight->noOfGroups;
501 for (i = 0; i < MAX_NO_OF_GROUPS; i++) {
502 blockSwitchingControlLeft->groupLen[i] =
503 blockSwitchingControlRight->groupLen[i];
504 }
505 }
506 } else if ((windowSequenceLeftOld == SHORT_WINDOW) &&
507 (windowSequenceRightOld != SHORT_WINDOW)) {
508 /* else use grouping of short-block channel */
509 blockSwitchingControlRight->noOfGroups =
510 blockSwitchingControlLeft->noOfGroups;
511 for (i = 0; i < MAX_NO_OF_GROUPS; i++) {
512 blockSwitchingControlRight->groupLen[i] =
513 blockSwitchingControlLeft->groupLen[i];
514 }
515 } else if ((windowSequenceRightOld == SHORT_WINDOW) &&
516 (windowSequenceLeftOld != SHORT_WINDOW)) {
517 blockSwitchingControlLeft->noOfGroups =
518 blockSwitchingControlRight->noOfGroups;
519 for (i = 0; i < MAX_NO_OF_GROUPS; i++) {
520 blockSwitchingControlLeft->groupLen[i] =
521 blockSwitchingControlRight->groupLen[i];
522 }
523 } else {
524 /* syncing a start and stop window ... */
525 blockSwitchingControlLeft->noOfGroups =
526 blockSwitchingControlRight->noOfGroups = 2;
527 blockSwitchingControlLeft->groupLen[0] =
528 blockSwitchingControlRight->groupLen[0] = 4;
529 blockSwitchingControlLeft->groupLen[1] =
530 blockSwitchingControlRight->groupLen[1] = 4;
531 }
532 } /* Short Blocks */
533 } else {
534 /* stereo, no common window */
535 if (blockSwitchingControlLeft->lastWindowSequence != SHORT_WINDOW) {
536 blockSwitchingControlLeft->noOfGroups = 1;
537 blockSwitchingControlLeft->groupLen[0] = 1;
538 for (i = 1; i < MAX_NO_OF_GROUPS; i++) {
539 blockSwitchingControlLeft->groupLen[i] = 0;
540 }
541 }
542 if (blockSwitchingControlRight->lastWindowSequence != SHORT_WINDOW) {
543 blockSwitchingControlRight->noOfGroups = 1;
544 blockSwitchingControlRight->groupLen[0] = 1;
545 for (i = 1; i < MAX_NO_OF_GROUPS; i++) {
546 blockSwitchingControlRight->groupLen[i] = 0;
547 }
548 }
549 } /* common window */
550 } else {
551 /* Mono */
552 if (blockSwitchingControlLeft->lastWindowSequence != SHORT_WINDOW) {
553 blockSwitchingControlLeft->noOfGroups = 1;
554 blockSwitchingControlLeft->groupLen[0] = 1;
555
556 for (i = 1; i < MAX_NO_OF_GROUPS; i++) {
557 blockSwitchingControlLeft->groupLen[i] = 0;
558 }
559 }
560 }
561 } /* allowShortFrames */
562
563 /* Translate LOWOV_WINDOW block type to a meaningful window shape. */
564 if (!blockSwitchingControlLeft->allowShortFrames) {
565 if (blockSwitchingControlLeft->lastWindowSequence != LONG_WINDOW &&
566 blockSwitchingControlLeft->lastWindowSequence != STOP_WINDOW) {
567 blockSwitchingControlLeft->lastWindowSequence = LONG_WINDOW;
568 blockSwitchingControlLeft->windowShape = LOL_WINDOW;
569 }
570 }
571 if (nChannels == 2) {
572 if (!blockSwitchingControlRight->allowShortFrames) {
573 if (blockSwitchingControlRight->lastWindowSequence != LONG_WINDOW &&
574 blockSwitchingControlRight->lastWindowSequence != STOP_WINDOW) {
575 blockSwitchingControlRight->lastWindowSequence = LONG_WINDOW;
576 blockSwitchingControlRight->windowShape = LOL_WINDOW;
577 }
578 }
579 }
580
581 return 0;
582 }
583