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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 /**************************** SBR decoder library ******************************
96 
97    Author(s):   Christian Griebel
98 
99    Description: Dynamic range control (DRC) decoder tool for SBR
100 
101 *******************************************************************************/
102 
103 #include "sbrdec_drc.h"
104 
105 /* DRC - Offset table for QMF interpolation. Shifted by one index position.
106    The table defines the (short) window borders rounded to the nearest QMF
107    timeslot. It has the size 16 because it is accessed with the
108    drcInterpolationScheme that is read from the bitstream with 4 bit. */
109 static const UCHAR winBorderToColMappingTab[2][16] = {
110     /*-1, 0, 1, 2,  3,  4,  5,  6,  7,  8 */
111     {0, 0, 4, 8, 12, 16, 20, 24, 28, 32, 32, 32, 32, 32, 32,
112      32}, /* 1024 framing */
113     {0, 0, 4, 8, 11, 15, 19, 23, 26, 30, 30, 30, 30, 30, 30,
114      30} /*  960 framing */
115 };
116 
117 /*!
118   \brief Initialize DRC QMF factors
119 
120   \hDrcData Handle to DRC channel data.
121 
122   \return none
123 */
sbrDecoder_drcInitChannel(HANDLE_SBR_DRC_CHANNEL hDrcData)124 void sbrDecoder_drcInitChannel(HANDLE_SBR_DRC_CHANNEL hDrcData) {
125   int band;
126 
127   if (hDrcData == NULL) {
128     return;
129   }
130 
131   for (band = 0; band < (64); band++) {
132     hDrcData->prevFact_mag[band] = FL2FXCONST_DBL(0.5f);
133   }
134 
135   for (band = 0; band < SBRDEC_MAX_DRC_BANDS; band++) {
136     hDrcData->currFact_mag[band] = FL2FXCONST_DBL(0.5f);
137     hDrcData->nextFact_mag[band] = FL2FXCONST_DBL(0.5f);
138   }
139 
140   hDrcData->prevFact_exp = 1;
141   hDrcData->currFact_exp = 1;
142   hDrcData->nextFact_exp = 1;
143 
144   hDrcData->numBandsCurr = 1;
145   hDrcData->numBandsNext = 1;
146 
147   hDrcData->winSequenceCurr = 0;
148   hDrcData->winSequenceNext = 0;
149 
150   hDrcData->drcInterpolationSchemeCurr = 0;
151   hDrcData->drcInterpolationSchemeNext = 0;
152 
153   hDrcData->enable = 0;
154 }
155 
156 /*!
157   \brief Swap DRC QMF scaling factors after they have been applied.
158 
159   \hDrcData Handle to DRC channel data.
160 
161   \return none
162 */
sbrDecoder_drcUpdateChannel(HANDLE_SBR_DRC_CHANNEL hDrcData)163 void sbrDecoder_drcUpdateChannel(HANDLE_SBR_DRC_CHANNEL hDrcData) {
164   if (hDrcData == NULL) {
165     return;
166   }
167   if (hDrcData->enable != 1) {
168     return;
169   }
170 
171   /* swap previous data */
172   FDKmemcpy(hDrcData->currFact_mag, hDrcData->nextFact_mag,
173             SBRDEC_MAX_DRC_BANDS * sizeof(FIXP_DBL));
174 
175   hDrcData->currFact_exp = hDrcData->nextFact_exp;
176 
177   hDrcData->numBandsCurr = hDrcData->numBandsNext;
178 
179   FDKmemcpy(hDrcData->bandTopCurr, hDrcData->bandTopNext,
180             SBRDEC_MAX_DRC_BANDS * sizeof(USHORT));
181 
182   hDrcData->drcInterpolationSchemeCurr = hDrcData->drcInterpolationSchemeNext;
183 
184   hDrcData->winSequenceCurr = hDrcData->winSequenceNext;
185 }
186 
187 /*!
188   \brief Apply DRC factors slot based.
189 
190   \hDrcData Handle to DRC channel data.
191   \qmfRealSlot Pointer to real valued QMF data of one time slot.
192   \qmfImagSlot Pointer to the imaginary QMF data of one time slot.
193   \col Number of the time slot.
194   \numQmfSubSamples Total number of time slots for one frame.
195   \scaleFactor Pointer to the out scale factor of the time slot.
196 
197   \return None.
198 */
sbrDecoder_drcApplySlot(HANDLE_SBR_DRC_CHANNEL hDrcData,FIXP_DBL * qmfRealSlot,FIXP_DBL * qmfImagSlot,int col,int numQmfSubSamples,int maxShift)199 void sbrDecoder_drcApplySlot(HANDLE_SBR_DRC_CHANNEL hDrcData,
200                              FIXP_DBL *qmfRealSlot, FIXP_DBL *qmfImagSlot,
201                              int col, int numQmfSubSamples, int maxShift) {
202   const UCHAR *winBorderToColMap;
203 
204   int band, bottomMdct, topMdct, bin, useLP;
205   int indx = numQmfSubSamples - (numQmfSubSamples >> 1) - 10; /* l_border */
206   int frameLenFlag = (numQmfSubSamples == 30) ? 1 : 0;
207   int frameSize = (frameLenFlag == 1) ? 960 : 1024;
208 
209   const FIXP_DBL *fact_mag = NULL;
210   INT fact_exp = 0;
211   UINT numBands = 0;
212   USHORT *bandTop = NULL;
213   int shortDrc = 0;
214 
215   FIXP_DBL alphaValue = FL2FXCONST_DBL(0.0f);
216 
217   if (hDrcData == NULL) {
218     return;
219   }
220   if (hDrcData->enable != 1) {
221     return;
222   }
223 
224   winBorderToColMap = winBorderToColMappingTab[frameLenFlag];
225 
226   useLP = (qmfImagSlot == NULL) ? 1 : 0;
227 
228   col += indx;
229   bottomMdct = 0;
230 
231   /* get respective data and calc interpolation factor */
232   if (col < (numQmfSubSamples >> 1)) {    /* first half of current frame */
233     if (hDrcData->winSequenceCurr != 2) { /* long window */
234       int j = col + (numQmfSubSamples >> 1);
235 
236       if (hDrcData->drcInterpolationSchemeCurr == 0) {
237         INT k = (frameLenFlag) ? 0x4444445 : 0x4000000;
238 
239         alphaValue = (FIXP_DBL)(j * k);
240       } else {
241         if (j >= (int)winBorderToColMap[hDrcData->drcInterpolationSchemeCurr]) {
242           alphaValue = (FIXP_DBL)MAXVAL_DBL;
243         }
244       }
245     } else { /* short windows */
246       shortDrc = 1;
247     }
248 
249     fact_mag = hDrcData->currFact_mag;
250     fact_exp = hDrcData->currFact_exp;
251     numBands = hDrcData->numBandsCurr;
252     bandTop = hDrcData->bandTopCurr;
253   } else if (col < numQmfSubSamples) {    /* second half of current frame */
254     if (hDrcData->winSequenceNext != 2) { /* next: long window */
255       int j = col - (numQmfSubSamples >> 1);
256 
257       if (hDrcData->drcInterpolationSchemeNext == 0) {
258         INT k = (frameLenFlag) ? 0x4444445 : 0x4000000;
259 
260         alphaValue = (FIXP_DBL)(j * k);
261       } else {
262         if (j >= (int)winBorderToColMap[hDrcData->drcInterpolationSchemeNext]) {
263           alphaValue = (FIXP_DBL)MAXVAL_DBL;
264         }
265       }
266 
267       fact_mag = hDrcData->nextFact_mag;
268       fact_exp = hDrcData->nextFact_exp;
269       numBands = hDrcData->numBandsNext;
270       bandTop = hDrcData->bandTopNext;
271     } else {                                /* next: short windows */
272       if (hDrcData->winSequenceCurr != 2) { /* current: long window */
273         alphaValue = (FIXP_DBL)0;
274 
275         fact_mag = hDrcData->nextFact_mag;
276         fact_exp = hDrcData->nextFact_exp;
277         numBands = hDrcData->numBandsNext;
278         bandTop = hDrcData->bandTopNext;
279       } else { /* current: short windows */
280         shortDrc = 1;
281 
282         fact_mag = hDrcData->currFact_mag;
283         fact_exp = hDrcData->currFact_exp;
284         numBands = hDrcData->numBandsCurr;
285         bandTop = hDrcData->bandTopCurr;
286       }
287     }
288   } else {                                /* first half of next frame */
289     if (hDrcData->winSequenceNext != 2) { /* long window */
290       int j = col - (numQmfSubSamples >> 1);
291 
292       if (hDrcData->drcInterpolationSchemeNext == 0) {
293         INT k = (frameLenFlag) ? 0x4444445 : 0x4000000;
294 
295         alphaValue = (FIXP_DBL)(j * k);
296       } else {
297         if (j >= (int)winBorderToColMap[hDrcData->drcInterpolationSchemeNext]) {
298           alphaValue = (FIXP_DBL)MAXVAL_DBL;
299         }
300       }
301     } else { /* short windows */
302       shortDrc = 1;
303     }
304 
305     fact_mag = hDrcData->nextFact_mag;
306     fact_exp = hDrcData->nextFact_exp;
307     numBands = hDrcData->numBandsNext;
308     bandTop = hDrcData->bandTopNext;
309 
310     col -= numQmfSubSamples;
311   }
312 
313   /* process bands */
314   for (band = 0; band < (int)numBands; band++) {
315     int bottomQmf, topQmf;
316 
317     FIXP_DBL drcFact_mag = (FIXP_DBL)MAXVAL_DBL;
318 
319     topMdct = (bandTop[band] + 1) << 2;
320 
321     if (!shortDrc) { /* long window */
322       if (frameLenFlag) {
323         /* 960 framing */
324         bottomQmf = fMultIfloor((FIXP_DBL)0x4444445, bottomMdct);
325         topQmf = fMultIfloor((FIXP_DBL)0x4444445, topMdct);
326 
327         topMdct = 30 * topQmf;
328       } else {
329         /* 1024 framing */
330         topMdct &= ~0x1f;
331 
332         bottomQmf = bottomMdct >> 5;
333         topQmf = topMdct >> 5;
334       }
335 
336       if (band == ((int)numBands - 1)) {
337         topQmf = (64);
338       }
339 
340       for (bin = bottomQmf; bin < topQmf; bin++) {
341         FIXP_DBL drcFact1_mag = hDrcData->prevFact_mag[bin];
342         FIXP_DBL drcFact2_mag = fact_mag[band];
343 
344         /* normalize scale factors */
345         if (hDrcData->prevFact_exp < maxShift) {
346           drcFact1_mag >>= maxShift - hDrcData->prevFact_exp;
347         }
348         if (fact_exp < maxShift) {
349           drcFact2_mag >>= maxShift - fact_exp;
350         }
351 
352         /* interpolate */
353         if (alphaValue == (FIXP_DBL)0) {
354           drcFact_mag = drcFact1_mag;
355         } else if (alphaValue == (FIXP_DBL)MAXVAL_DBL) {
356           drcFact_mag = drcFact2_mag;
357         } else {
358           drcFact_mag =
359               fMult(alphaValue, drcFact2_mag) +
360               fMult(((FIXP_DBL)MAXVAL_DBL - alphaValue), drcFact1_mag);
361         }
362 
363         /* apply scaling */
364         qmfRealSlot[bin] = fMult(qmfRealSlot[bin], drcFact_mag);
365         if (!useLP) {
366           qmfImagSlot[bin] = fMult(qmfImagSlot[bin], drcFact_mag);
367         }
368 
369         /* save previous factors */
370         if (col == (numQmfSubSamples >> 1) - 1) {
371           hDrcData->prevFact_mag[bin] = fact_mag[band];
372         }
373       }
374     } else { /* short windows */
375       unsigned startWinIdx, stopWinIdx;
376       int startCol, stopCol;
377       FIXP_DBL invFrameSizeDiv8 =
378           (frameLenFlag) ? (FIXP_DBL)0x1111112 : (FIXP_DBL)0x1000000;
379 
380       /* limit top at the frame borders */
381       if (topMdct < 0) {
382         topMdct = 0;
383       }
384       if (topMdct >= frameSize) {
385         topMdct = frameSize - 1;
386       }
387 
388       if (frameLenFlag) {
389         /*  960 framing */
390         topMdct = fMultIfloor((FIXP_DBL)0x78000000,
391                               fMultIfloor((FIXP_DBL)0x22222223, topMdct) << 2);
392 
393         startWinIdx = fMultIfloor(invFrameSizeDiv8, bottomMdct) +
394                       1; /* winBorderToColMap table has offset of 1 */
395         stopWinIdx = fMultIceil(invFrameSizeDiv8 - (FIXP_DBL)1, topMdct) + 1;
396       } else {
397         /* 1024 framing */
398         topMdct &= ~0x03;
399 
400         startWinIdx = fMultIfloor(invFrameSizeDiv8, bottomMdct) + 1;
401         stopWinIdx = fMultIceil(invFrameSizeDiv8, topMdct) + 1;
402       }
403 
404       /* startCol is truncated to the nearest corresponding start subsample in
405          the QMF of the short window bottom is present in:*/
406       startCol = (int)winBorderToColMap[startWinIdx];
407 
408       /* stopCol is rounded upwards to the nearest corresponding stop subsample
409          in the QMF of the short window top is present in. */
410       stopCol = (int)winBorderToColMap[stopWinIdx];
411 
412       bottomQmf = fMultIfloor(invFrameSizeDiv8,
413                               ((bottomMdct % (numQmfSubSamples << 2)) << 5));
414       topQmf = fMultIfloor(invFrameSizeDiv8,
415                            ((topMdct % (numQmfSubSamples << 2)) << 5));
416 
417       /* extend last band */
418       if (band == ((int)numBands - 1)) {
419         topQmf = (64);
420         stopCol = numQmfSubSamples;
421         stopWinIdx = 10;
422       }
423 
424       if (topQmf == 0) {
425         if (frameLenFlag) {
426           FIXP_DBL rem = fMult(invFrameSizeDiv8,
427                                (FIXP_DBL)(topMdct << (DFRACT_BITS - 12)));
428           if ((LONG)rem & (LONG)0x1F) {
429             stopWinIdx -= 1;
430             stopCol = (int)winBorderToColMap[stopWinIdx];
431           }
432         }
433         topQmf = (64);
434       }
435 
436       /* save previous factors */
437       if (stopCol == numQmfSubSamples) {
438         int tmpBottom = bottomQmf;
439 
440         if ((int)winBorderToColMap[8] > startCol) {
441           tmpBottom = 0; /* band starts in previous short window */
442         }
443 
444         for (bin = tmpBottom; bin < topQmf; bin++) {
445           hDrcData->prevFact_mag[bin] = fact_mag[band];
446         }
447       }
448 
449       /* apply */
450       if ((col >= startCol) && (col < stopCol)) {
451         if (col >= (int)winBorderToColMap[startWinIdx + 1]) {
452           bottomQmf = 0; /* band starts in previous short window */
453         }
454         if (col < (int)winBorderToColMap[stopWinIdx - 1]) {
455           topQmf = (64); /* band ends in next short window */
456         }
457 
458         drcFact_mag = fact_mag[band];
459 
460         /* normalize scale factor */
461         if (fact_exp < maxShift) {
462           drcFact_mag >>= maxShift - fact_exp;
463         }
464 
465         /* apply scaling */
466         for (bin = bottomQmf; bin < topQmf; bin++) {
467           qmfRealSlot[bin] = fMult(qmfRealSlot[bin], drcFact_mag);
468           if (!useLP) {
469             qmfImagSlot[bin] = fMult(qmfImagSlot[bin], drcFact_mag);
470           }
471         }
472       }
473     }
474 
475     bottomMdct = topMdct;
476   } /* end of bands loop */
477 
478   if (col == (numQmfSubSamples >> 1) - 1) {
479     hDrcData->prevFact_exp = fact_exp;
480   }
481 }
482 
483 /*!
484   \brief Apply DRC factors frame based.
485 
486   \hDrcData Handle to DRC channel data.
487   \qmfRealSlot Pointer to real valued QMF data of the whole frame.
488   \qmfImagSlot Pointer to the imaginary QMF data of the whole frame.
489   \numQmfSubSamples Total number of time slots for one frame.
490   \scaleFactor Pointer to the out scale factor of the frame.
491 
492   \return None.
493 */
sbrDecoder_drcApply(HANDLE_SBR_DRC_CHANNEL hDrcData,FIXP_DBL ** QmfBufferReal,FIXP_DBL ** QmfBufferImag,int numQmfSubSamples,int * scaleFactor)494 void sbrDecoder_drcApply(HANDLE_SBR_DRC_CHANNEL hDrcData,
495                          FIXP_DBL **QmfBufferReal, FIXP_DBL **QmfBufferImag,
496                          int numQmfSubSamples, int *scaleFactor) {
497   int col;
498   int maxShift = 0;
499 
500   if (hDrcData == NULL) {
501     return;
502   }
503   if (hDrcData->enable == 0) {
504     return; /* Avoid changing the scaleFactor even though the processing is
505                disabled. */
506   }
507 
508   /* get max scale factor */
509   if (hDrcData->prevFact_exp > maxShift) {
510     maxShift = hDrcData->prevFact_exp;
511   }
512   if (hDrcData->currFact_exp > maxShift) {
513     maxShift = hDrcData->currFact_exp;
514   }
515   if (hDrcData->nextFact_exp > maxShift) {
516     maxShift = hDrcData->nextFact_exp;
517   }
518 
519   for (col = 0; col < numQmfSubSamples; col++) {
520     FIXP_DBL *qmfSlotReal = QmfBufferReal[col];
521     FIXP_DBL *qmfSlotImag = (QmfBufferImag == NULL) ? NULL : QmfBufferImag[col];
522 
523     sbrDecoder_drcApplySlot(hDrcData, qmfSlotReal, qmfSlotImag, col,
524                             numQmfSubSamples, maxShift);
525   }
526 
527   *scaleFactor += maxShift;
528 }
529