1
2 /* -----------------------------------------------------------------------------------------------------------
3 Software License for The Fraunhofer FDK AAC Codec Library for Android
4
5 � Copyright 1995 - 2013 Fraunhofer-Gesellschaft zur F�rderung 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@iis.fraunhofer.de
82 ----------------------------------------------------------------------------------------------------------- */
83
84 /*************************** Fraunhofer IIS FDK Tools **********************
85
86 Author(s): Josef Hoepfl, Manuel Jander
87 Description: MDCT routines
88
89 ******************************************************************************/
90
91 #include "mdct.h"
92
93
94 #include "FDK_tools_rom.h"
95 #include "dct.h"
96 #include "fixpoint_math.h"
97
98
mdct_init(H_MDCT hMdct,FIXP_DBL * overlap,INT overlapBufferSize)99 void mdct_init( H_MDCT hMdct,
100 FIXP_DBL *overlap,
101 INT overlapBufferSize )
102 {
103 hMdct->overlap.freq = overlap;
104 //FDKmemclear(overlap, overlapBufferSize*sizeof(FIXP_DBL));
105 hMdct->prev_fr = 0;
106 hMdct->prev_nr = 0;
107 hMdct->prev_tl = 0;
108 hMdct->ov_size = overlapBufferSize;
109 }
110
111
imdct_gain(FIXP_DBL * pGain_m,int * pGain_e,int tl)112 void imdct_gain(FIXP_DBL *pGain_m, int *pGain_e, int tl)
113 {
114 FIXP_DBL gain_m = *pGain_m;
115 int gain_e = *pGain_e;
116 int log2_tl;
117
118 log2_tl = DFRACT_BITS-1-fNormz((FIXP_DBL)tl);
119
120 gain_e += -MDCT_OUTPUT_GAIN - log2_tl - MDCT_OUT_HEADROOM + 1;
121
122 /* Detect non-radix 2 transform length and add amplitude compensation factor
123 which cannot be included into the exponent above */
124 switch ( (tl) >> (log2_tl - 2) ) {
125 case 0x7: /* 10 ms, 1/tl = 1.0/(FDKpow(2.0, -log2_tl) * 0.53333333333333333333) */
126 if (gain_m == (FIXP_DBL)0) {
127 gain_m = FL2FXCONST_DBL(0.53333333333333333333f);
128 } else {
129 gain_m = fMult(gain_m, FL2FXCONST_DBL(0.53333333333333333333f));
130 }
131 break;
132 case 0x6: /* 3/4 of radix 2, 1/tl = 1.0/(FDKpow(2.0, -log2_tl) * 2.0/3.0) */
133 if (gain_m == (FIXP_DBL)0) {
134 gain_m = FL2FXCONST_DBL(2.0/3.0f);
135 } else {
136 gain_m = fMult(gain_m, FL2FXCONST_DBL(2.0/3.0f));
137 }
138 break;
139 case 0x4:
140 /* radix 2, nothing to do. */
141 break;
142 default:
143 /* unsupported */
144 FDK_ASSERT(0);
145 break;
146 }
147
148 *pGain_m = gain_m;
149 *pGain_e = gain_e;
150 }
151
imdct_drain(H_MDCT hMdct,FIXP_DBL * output,INT nrSamplesRoom)152 INT imdct_drain(
153 H_MDCT hMdct,
154 FIXP_DBL *output,
155 INT nrSamplesRoom
156 )
157 {
158 int buffered_samples = 0;
159
160 if (nrSamplesRoom > 0) {
161 buffered_samples = hMdct->ov_offset;
162
163 FDK_ASSERT(buffered_samples <= nrSamplesRoom);
164
165 if (buffered_samples > 0) {
166 FDKmemcpy(output, hMdct->overlap.time, buffered_samples*sizeof(FIXP_DBL));
167 hMdct->ov_offset = 0;
168 }
169 }
170 return buffered_samples;
171 }
172
imdct_copy_ov_and_nr(H_MDCT hMdct,FIXP_DBL * pTimeData,INT nrSamples)173 INT imdct_copy_ov_and_nr(
174 H_MDCT hMdct,
175 FIXP_DBL * pTimeData,
176 INT nrSamples
177 )
178 {
179 FIXP_DBL *pOvl;
180 int nt, nf, i;
181
182 nt = fMin(hMdct->ov_offset, nrSamples);
183 nrSamples -= nt;
184 nf = fMin(hMdct->prev_nr, nrSamples);
185 nrSamples -= nf;
186 FDKmemcpy(pTimeData, hMdct->overlap.time, nt*sizeof(FIXP_DBL));
187 pTimeData += nt;
188
189 pOvl = hMdct->overlap.freq + hMdct->ov_size - 1;
190 for (i=0; i<nf; i++) {
191 FIXP_DBL x = - (*pOvl--);
192 *pTimeData = IMDCT_SCALE_DBL(x);
193 pTimeData ++;
194 }
195
196 return (nt+nf);
197 }
198
imdct_adapt_parameters(H_MDCT hMdct,int * pfl,int * pnl,int tl,const FIXP_WTP * wls,int noOutSamples)199 void imdct_adapt_parameters(H_MDCT hMdct, int *pfl, int *pnl, int tl, const FIXP_WTP *wls, int noOutSamples)
200 {
201 int fl = *pfl, nl = *pnl;
202 int window_diff, use_current = 0, use_previous = 0;
203 if (hMdct->prev_tl == 0) {
204 hMdct->prev_wrs = wls;
205 hMdct->prev_fr = fl;
206 hMdct->prev_nr = (noOutSamples-fl)>>1;
207 hMdct->prev_tl = noOutSamples;
208 hMdct->ov_offset = 0;
209 use_current = 1;
210 }
211
212 window_diff = (hMdct->prev_fr - fl)>>1;
213
214 /* check if the previous window slope can be adjusted to match the current window slope */
215 if (hMdct->prev_nr + window_diff > 0) {
216 use_current = 1;
217 }
218 /* check if the current window slope can be adjusted to match the previous window slope */
219 if (nl - window_diff > 0 ) {
220 use_previous = 1;
221 }
222
223 /* if both is possible choose the larger of both window slope lengths */
224 if (use_current && use_previous) {
225 if (fl < hMdct->prev_fr) {
226 use_current = 0;
227 } else {
228 use_previous = 0;
229 }
230 }
231 /*
232 * If the previous transform block is big enough, enlarge previous window overlap,
233 * if not, then shrink current window overlap.
234 */
235 if (use_current) {
236 hMdct->prev_nr += window_diff;
237 hMdct->prev_fr = fl;
238 hMdct->prev_wrs = wls;
239 } else {
240 nl -= window_diff;
241 fl = hMdct->prev_fr;
242 }
243
244 *pfl = fl;
245 *pnl = nl;
246 }
247
imdct_block(H_MDCT hMdct,FIXP_DBL * output,FIXP_DBL * spectrum,const SHORT scalefactor[],const INT nSpec,const INT noOutSamples,const INT tl,const FIXP_WTP * wls,INT fl,const FIXP_WTP * wrs,const INT fr,FIXP_DBL gain)248 INT imdct_block(
249 H_MDCT hMdct,
250 FIXP_DBL *output,
251 FIXP_DBL *spectrum,
252 const SHORT scalefactor[],
253 const INT nSpec,
254 const INT noOutSamples,
255 const INT tl,
256 const FIXP_WTP *wls,
257 INT fl,
258 const FIXP_WTP *wrs,
259 const INT fr,
260 FIXP_DBL gain
261 )
262 {
263 FIXP_DBL *pOvl;
264 FIXP_DBL *pOut0 = output, *pOut1;
265 INT nl, nr;
266 int w, i, nrSamples = 0, specShiftScale, transform_gain_e = 0;
267
268 /* Derive NR and NL */
269 nr = (tl - fr)>>1;
270 nl = (tl - fl)>>1;
271
272 /* Include 2/N IMDCT gain into gain factor and exponent. */
273 imdct_gain(&gain, &transform_gain_e, tl);
274
275 /* Detect FRprevious / FL mismatches and override parameters accordingly */
276 if (hMdct->prev_fr != fl) {
277 imdct_adapt_parameters(hMdct, &fl, &nl, tl, wls, noOutSamples);
278 }
279
280 pOvl = hMdct->overlap.freq + hMdct->ov_size - 1;
281
282 if ( noOutSamples > nrSamples ) {
283 /* Purge buffered output. */
284 for (i=0; i<hMdct->ov_offset; i++) {
285 *pOut0 = hMdct->overlap.time[i];
286 pOut0 ++;
287 }
288 nrSamples = hMdct->ov_offset;
289 hMdct->ov_offset = 0;
290 }
291
292 for (w=0; w<nSpec; w++)
293 {
294 FIXP_DBL *pSpec, *pCurr;
295 const FIXP_WTP *pWindow;
296
297 specShiftScale = transform_gain_e;
298
299 /* Setup window pointers */
300 pWindow = hMdct->prev_wrs;
301
302 /* Current spectrum */
303 pSpec = spectrum+w*tl;
304
305 /* DCT IV of current spectrum. */
306 dct_IV(pSpec, tl, &specShiftScale);
307
308 /* Optional scaling of time domain - no yet windowed - of current spectrum */
309 /* and de-scale current spectrum signal (time domain, no yet windowed) */
310 if (gain != (FIXP_DBL)0) {
311 scaleValuesWithFactor(pSpec, gain, tl, scalefactor[w] + specShiftScale);
312 } else {
313 scaleValues(pSpec, tl, scalefactor[w] + specShiftScale);
314 }
315
316 if ( noOutSamples <= nrSamples ) {
317 /* Divert output first half to overlap buffer if we already got enough output samples. */
318 pOut0 = hMdct->overlap.time + hMdct->ov_offset;
319 hMdct->ov_offset += hMdct->prev_nr + fl/2;
320 } else {
321 /* Account output samples */
322 nrSamples += hMdct->prev_nr + fl/2;
323 }
324
325 /* NR output samples 0 .. NR. -overlap[TL/2..TL/2-NR] */
326 for (i=0; i<hMdct->prev_nr; i++) {
327 FIXP_DBL x = - (*pOvl--);
328 *pOut0 = IMDCT_SCALE_DBL(x);
329 pOut0 ++;
330 }
331
332 if ( noOutSamples <= nrSamples ) {
333 /* Divert output second half to overlap buffer if we already got enough output samples. */
334 pOut1 = hMdct->overlap.time + hMdct->ov_offset + fl/2 - 1;
335 hMdct->ov_offset += fl/2 + nl;
336 } else {
337 pOut1 = pOut0 + (fl - 1);
338 nrSamples += fl/2 + nl;
339 }
340
341 /* output samples before window crossing point NR .. TL/2. -overlap[TL/2-NR..TL/2-NR-FL/2] + current[NR..TL/2] */
342 /* output samples after window crossing point TL/2 .. TL/2+FL/2. -overlap[0..FL/2] - current[TL/2..FL/2] */
343 pCurr = pSpec + tl - fl/2;
344 for (i=0; i<fl/2; i++) {
345 FIXP_DBL x0, x1;
346
347 cplxMult(&x1, &x0, *pCurr++, - *pOvl--, pWindow[i]);
348 *pOut0 = IMDCT_SCALE_DBL(x0);
349 *pOut1 = IMDCT_SCALE_DBL(-x1);
350 pOut0 ++;
351 pOut1 --;
352 }
353 pOut0 += (fl/2);
354
355 /* NL output samples TL/2+FL/2..TL. - current[FL/2..0] */
356 pOut1 += (fl/2) + 1;
357 pCurr = pSpec + tl - fl/2 - 1;
358 for (i=0; i<nl; i++) {
359 FIXP_DBL x = - (*pCurr--);
360 *pOut1 = IMDCT_SCALE_DBL(x);
361 pOut1 ++;
362 }
363
364 /* Set overlap source pointer for next window pOvl = pSpec + tl/2 - 1; */
365 pOvl = pSpec + tl/2 - 1;
366
367 /* Previous window values. */
368 hMdct->prev_nr = nr;
369 hMdct->prev_fr = fr;
370 hMdct->prev_tl = tl;
371 hMdct->prev_wrs = wrs;
372 }
373
374 /* Save overlap */
375
376 pOvl = hMdct->overlap.freq + hMdct->ov_size - tl/2;
377 FDK_ASSERT(pOvl >= hMdct->overlap.time + hMdct->ov_offset);
378 FDK_ASSERT(tl/2 <= hMdct->ov_size);
379 for (i=0; i<tl/2; i++) {
380 pOvl[i] = spectrum[i+(nSpec-1)*tl];
381 }
382
383 return nrSamples;
384 }
385
386