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 decoder library ******************************
96
97 Author(s): Josef Hoepfl
98
99 Description: perceptual noise substitution tool
100
101 *******************************************************************************/
102
103 #include "aacdec_pns.h"
104
105 #include "aac_ram.h"
106 #include "aac_rom.h"
107 #include "channelinfo.h"
108 #include "block.h"
109 #include "FDK_bitstream.h"
110
111 #include "genericStds.h"
112
113 #define NOISE_OFFSET 90 /* cf. ISO 14496-3 p. 175 */
114
115 /*!
116 \brief Reset InterChannel and PNS data
117
118 The function resets the InterChannel and PNS data
119 */
CPns_ResetData(CPnsData * pPnsData,CPnsInterChannelData * pPnsInterChannelData)120 void CPns_ResetData(CPnsData *pPnsData,
121 CPnsInterChannelData *pPnsInterChannelData) {
122 FDK_ASSERT(pPnsData != NULL);
123 FDK_ASSERT(pPnsInterChannelData != NULL);
124 /* Assign pointer always, since pPnsData is not persistent data */
125 pPnsData->pPnsInterChannelData = pPnsInterChannelData;
126 pPnsData->PnsActive = 0;
127 pPnsData->CurrentEnergy = 0;
128
129 FDKmemclear(pPnsData->pnsUsed, (8 * 16) * sizeof(UCHAR));
130 FDKmemclear(pPnsInterChannelData->correlated, (8 * 16) * sizeof(UCHAR));
131 }
132
133 /*!
134 \brief Update PNS noise generator state.
135
136 The function sets the seed for PNS noise generation.
137 It can be used to link two or more channels in terms of PNS.
138 */
CPns_UpdateNoiseState(CPnsData * pPnsData,INT * currentSeed,INT * randomSeed)139 void CPns_UpdateNoiseState(CPnsData *pPnsData, INT *currentSeed,
140 INT *randomSeed) {
141 /* use pointer because seed has to be
142 same, left and right channel ! */
143 pPnsData->currentSeed = currentSeed;
144 pPnsData->randomSeed = randomSeed;
145 }
146
147 /*!
148 \brief Indicates if PNS is used
149
150 The function returns a value indicating whether PNS is used or not
151 acordding to the noise energy
152
153 \return PNS used
154 */
CPns_IsPnsUsed(const CPnsData * pPnsData,const int group,const int band)155 int CPns_IsPnsUsed(const CPnsData *pPnsData, const int group, const int band) {
156 unsigned pns_band = group * 16 + band;
157
158 return pPnsData->pnsUsed[pns_band] & (UCHAR)1;
159 }
160
161 /*!
162 \brief Set correlation
163
164 The function activates the noise correlation between the channel pair
165 */
CPns_SetCorrelation(CPnsData * pPnsData,const int group,const int band,const int outofphase)166 void CPns_SetCorrelation(CPnsData *pPnsData, const int group, const int band,
167 const int outofphase) {
168 CPnsInterChannelData *pInterChannelData = pPnsData->pPnsInterChannelData;
169 unsigned pns_band = group * 16 + band;
170
171 pInterChannelData->correlated[pns_band] = (outofphase) ? 3 : 1;
172 }
173
174 /*!
175 \brief Indicates if correlation is used
176
177 The function indicates if the noise correlation between the channel pair
178 is activated
179
180 \return PNS is correlated
181 */
CPns_IsCorrelated(const CPnsData * pPnsData,const int group,const int band)182 static int CPns_IsCorrelated(const CPnsData *pPnsData, const int group,
183 const int band) {
184 CPnsInterChannelData *pInterChannelData = pPnsData->pPnsInterChannelData;
185 unsigned pns_band = group * 16 + band;
186
187 return (pInterChannelData->correlated[pns_band] & 0x01) ? 1 : 0;
188 }
189
190 /*!
191 \brief Indicates if correlated out of phase mode is used.
192
193 The function indicates if the noise correlation between the channel pair
194 is activated in out-of-phase mode.
195
196 \return PNS is out-of-phase
197 */
CPns_IsOutOfPhase(const CPnsData * pPnsData,const int group,const int band)198 static int CPns_IsOutOfPhase(const CPnsData *pPnsData, const int group,
199 const int band) {
200 CPnsInterChannelData *pInterChannelData = pPnsData->pPnsInterChannelData;
201 unsigned pns_band = group * 16 + band;
202
203 return (pInterChannelData->correlated[pns_band] & 0x02) ? 1 : 0;
204 }
205
206 /*!
207 \brief Read PNS information
208
209 The function reads the PNS information from the bitstream
210 */
CPns_Read(CPnsData * pPnsData,HANDLE_FDK_BITSTREAM bs,const CodeBookDescription * hcb,SHORT * pScaleFactor,UCHAR global_gain,int band,int group)211 void CPns_Read(CPnsData *pPnsData, HANDLE_FDK_BITSTREAM bs,
212 const CodeBookDescription *hcb, SHORT *pScaleFactor,
213 UCHAR global_gain, int band, int group /* = 0 */) {
214 int delta;
215 UINT pns_band = group * 16 + band;
216
217 if (pPnsData->PnsActive) {
218 /* Next PNS band case */
219 delta = CBlock_DecodeHuffmanWord(bs, hcb) - 60;
220 } else {
221 /* First PNS band case */
222 int noiseStartValue = FDKreadBits(bs, 9);
223
224 delta = noiseStartValue - 256;
225 pPnsData->PnsActive = 1;
226 pPnsData->CurrentEnergy = global_gain - NOISE_OFFSET;
227 }
228
229 pPnsData->CurrentEnergy += delta;
230 pScaleFactor[pns_band] = pPnsData->CurrentEnergy;
231
232 pPnsData->pnsUsed[pns_band] = 1;
233 }
234
235 /**
236 * \brief Generate a vector of noise of given length. The noise values are
237 * scaled in order to yield a noise energy of 1.0
238 * \param spec pointer to were the noise values will be written to.
239 * \param size amount of noise values to be generated.
240 * \param pRandomState pointer to the state of the random generator being used.
241 * \return exponent of generated noise vector.
242 */
GenerateRandomVector(FIXP_DBL * RESTRICT spec,int size,int * pRandomState)243 static int GenerateRandomVector(FIXP_DBL *RESTRICT spec, int size,
244 int *pRandomState) {
245 int i, invNrg_e = 0, nrg_e = 0;
246 FIXP_DBL invNrg_m, nrg_m = FL2FXCONST_DBL(0.0f);
247 FIXP_DBL *RESTRICT ptr = spec;
248 int randomState = *pRandomState;
249
250 #define GEN_NOISE_NRG_SCALE 7
251
252 /* Generate noise and calculate energy. */
253 for (i = 0; i < size; i++) {
254 randomState =
255 (((INT64)1664525 * randomState) + (INT64)1013904223) & 0xFFFFFFFF;
256 nrg_m = fPow2AddDiv2(nrg_m, (FIXP_DBL)randomState >> GEN_NOISE_NRG_SCALE);
257 *ptr++ = (FIXP_DBL)randomState;
258 }
259 nrg_e = GEN_NOISE_NRG_SCALE * 2 + 1;
260
261 /* weight noise with = 1 / sqrt_nrg; */
262 invNrg_m = invSqrtNorm2(nrg_m << 1, &invNrg_e);
263 invNrg_e += -((nrg_e - 1) >> 1);
264
265 for (i = size; i--;) {
266 spec[i] = fMult(spec[i], invNrg_m);
267 }
268
269 /* Store random state */
270 *pRandomState = randomState;
271
272 return invNrg_e;
273 }
274
ScaleBand(FIXP_DBL * RESTRICT spec,int size,int scaleFactor,int specScale,int noise_e,int out_of_phase)275 static void ScaleBand(FIXP_DBL *RESTRICT spec, int size, int scaleFactor,
276 int specScale, int noise_e, int out_of_phase) {
277 int i, shift, sfExponent;
278 FIXP_DBL sfMatissa;
279
280 /* Get gain from scale factor value = 2^(scaleFactor * 0.25) */
281 sfMatissa = MantissaTable[scaleFactor & 0x03][0];
282 /* sfExponent = (scaleFactor >> 2) + ExponentTable[scaleFactor & 0x03][0]; */
283 /* Note: ExponentTable[scaleFactor & 0x03][0] is always 1. */
284 sfExponent = (scaleFactor >> 2) + 1;
285
286 if (out_of_phase != 0) {
287 sfMatissa = -sfMatissa;
288 }
289
290 /* +1 because of fMultDiv2 below. */
291 shift = sfExponent - specScale + 1 + noise_e;
292
293 /* Apply gain to noise values */
294 if (shift >= 0) {
295 shift = fixMin(shift, DFRACT_BITS - 1);
296 for (i = size; i-- != 0;) {
297 spec[i] = fMultDiv2(spec[i], sfMatissa) << shift;
298 }
299 } else {
300 shift = fixMin(-shift, DFRACT_BITS - 1);
301 for (i = size; i-- != 0;) {
302 spec[i] = fMultDiv2(spec[i], sfMatissa) >> shift;
303 }
304 }
305 }
306
307 /*!
308 \brief Apply PNS
309
310 The function applies PNS (i.e. it generates noise) on the bands
311 flagged as noisy bands
312
313 */
CPns_Apply(const CPnsData * pPnsData,const CIcsInfo * pIcsInfo,SPECTRAL_PTR pSpectrum,const SHORT * pSpecScale,const SHORT * pScaleFactor,const SamplingRateInfo * pSamplingRateInfo,const INT granuleLength,const int channel)314 void CPns_Apply(const CPnsData *pPnsData, const CIcsInfo *pIcsInfo,
315 SPECTRAL_PTR pSpectrum, const SHORT *pSpecScale,
316 const SHORT *pScaleFactor,
317 const SamplingRateInfo *pSamplingRateInfo,
318 const INT granuleLength, const int channel) {
319 if (pPnsData->PnsActive) {
320 const short *BandOffsets =
321 GetScaleFactorBandOffsets(pIcsInfo, pSamplingRateInfo);
322
323 int ScaleFactorBandsTransmitted = GetScaleFactorBandsTransmitted(pIcsInfo);
324
325 for (int window = 0, group = 0; group < GetWindowGroups(pIcsInfo);
326 group++) {
327 for (int groupwin = 0; groupwin < GetWindowGroupLength(pIcsInfo, group);
328 groupwin++, window++) {
329 FIXP_DBL *spectrum = SPEC(pSpectrum, window, granuleLength);
330
331 for (int band = 0; band < ScaleFactorBandsTransmitted; band++) {
332 if (CPns_IsPnsUsed(pPnsData, group, band)) {
333 UINT pns_band = window * 16 + band;
334
335 int bandWidth = BandOffsets[band + 1] - BandOffsets[band];
336 int noise_e;
337
338 FDK_ASSERT(bandWidth >= 0);
339
340 if (channel > 0 && CPns_IsCorrelated(pPnsData, group, band)) {
341 noise_e =
342 GenerateRandomVector(spectrum + BandOffsets[band], bandWidth,
343 &pPnsData->randomSeed[pns_band]);
344 } else {
345 pPnsData->randomSeed[pns_band] = *pPnsData->currentSeed;
346
347 noise_e = GenerateRandomVector(spectrum + BandOffsets[band],
348 bandWidth, pPnsData->currentSeed);
349 }
350
351 int outOfPhase = CPns_IsOutOfPhase(pPnsData, group, band);
352
353 ScaleBand(spectrum + BandOffsets[band], bandWidth,
354 pScaleFactor[group * 16 + band], pSpecScale[window],
355 noise_e, outOfPhase);
356 }
357 }
358 }
359 }
360 }
361 }
362