1 2/* ----------------------------------------------------------------------------------------------------------- 3Software 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 9The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements 10the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio. 11This FDK AAC Codec software is intended to be used on a wide variety of Android devices. 12 13AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual 14audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by 15independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part 16of the MPEG specifications. 17 18Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer) 19may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners 20individually for the purpose of encoding or decoding bit streams in products that are compliant with 21the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license 22these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec 23software may already be covered under those patent licenses when it is used for those licensed purposes only. 24 25Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality, 26are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional 27applications information and documentation. 28 292. COPYRIGHT LICENSE 30 31Redistribution and use in source and binary forms, with or without modification, are permitted without 32payment of copyright license fees provided that you satisfy the following conditions: 33 34You must retain the complete text of this software license in redistributions of the FDK AAC Codec or 35your modifications thereto in source code form. 36 37You must retain the complete text of this software license in the documentation and/or other materials 38provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form. 39You must make available free of charge copies of the complete source code of the FDK AAC Codec and your 40modifications thereto to recipients of copies in binary form. 41 42The name of Fraunhofer may not be used to endorse or promote products derived from this library without 43prior written permission. 44 45You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec 46software or your modifications thereto. 47 48Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software 49and 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." 52 533. NO PATENT LICENSE 54 55NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer, 56ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with 57respect to this software. 58 59You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized 60by appropriate patent licenses. 61 624. DISCLAIMER 63 64This 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 66of merchantability and fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 67CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages, 68including but not limited to procurement of substitute goods or services; loss of use, data, or profits, 69or business interruption, however caused and on any theory of liability, whether in contract, strict 70liability, or tort (including negligence), arising in any way out of the use of this software, even if 71advised of the possibility of such damage. 72 735. CONTACT INFORMATION 74 75Fraunhofer Institute for Integrated Circuits IIS 76Attention: Audio and Multimedia Departments - FDK AAC LL 77Am Wolfsmantel 33 7891058 Erlangen, Germany 79 80www.iis.fraunhofer.de/amm 81amm-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 99void 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 112void 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 152INT 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 173INT 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 199void 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 248INT 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