libAACenc/src/quantize.cpp

   1
   2 /* -----------------------------------------------------------------------------------------------------------
   3 Software License for The Fraunhofer FDK AAC Codec Library for Android
   4
   5 © Copyright  1995 - 2013 Fraunhofer-Gesellschaft zur Förderung 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 /******************************** MPEG Audio Encoder **************************
  85
  86    Initial author:       M.Werner
  87    contents/description: Quantization
  88
  89 ******************************************************************************/
  90
  91 #include "quantize.h"
  92
  93 #include "aacEnc_rom.h"
  94
  95 /*****************************************************************************
  96
  97     functionname: FDKaacEnc_quantizeLines
  98     description: quantizes spectrum lines
  99     returns:
 100     input: global gain, number of lines to process, spectral data
 101     output: quantized spectrum
 102
 103 *****************************************************************************/
 104 static void FDKaacEnc_quantizeLines(INT      gain,
 105                           INT      noOfLines,
 106                           FIXP_DBL *mdctSpectrum,
 107                           SHORT      *quaSpectrum)
 108 {
 109   int   line;
 110   FIXP_DBL k = FL2FXCONST_DBL(-0.0946f + 0.5f)>>16;
 111   FIXP_QTD quantizer = FDKaacEnc_quantTableQ[(-gain)&3];
 112   INT      quantizershift = ((-gain)>>2)+1;
 113
 114
 115   for (line = 0; line < noOfLines; line++)
 116   {
 117     FIXP_DBL accu = fMultDiv2(mdctSpectrum[line],quantizer);
 118
 119     if (accu < FL2FXCONST_DBL(0.0f))
 120     {
 121       accu=-accu;
 122       /* normalize */
 123       INT   accuShift = CntLeadingZeros(accu) - 1;  /* CountLeadingBits() is not necessary here since test value is always > 0 */
 124       accu <<= accuShift;
 125       INT tabIndex = (INT)(accu>>(DFRACT_BITS-2-MANT_DIGITS))&(~MANT_SIZE);
 126       INT totalShift = quantizershift-accuShift+1;
 127       accu = fMultDiv2(FDKaacEnc_mTab_3_4[tabIndex],FDKaacEnc_quantTableE[totalShift&3]);
 128       totalShift = (16-4)-(3*(totalShift>>2));
 129       FDK_ASSERT(totalShift >=0); /* MAX_QUANT_VIOLATION */
 130       accu >>= fixMin(totalShift,DFRACT_BITS-1);
 131       quaSpectrum[line] = (SHORT)(-((LONG)(k + accu) >> (DFRACT_BITS-1-16)));
 132     }
 133     else if(accu > FL2FXCONST_DBL(0.0f))
 134     {
 135       /* normalize */
 136       INT   accuShift = CntLeadingZeros(accu) - 1;  /* CountLeadingBits() is not necessary here since test value is always > 0 */
 137       accu <<= accuShift;
 138       INT tabIndex = (INT)(accu>>(DFRACT_BITS-2-MANT_DIGITS))&(~MANT_SIZE);
 139       INT totalShift = quantizershift-accuShift+1;
 140       accu = fMultDiv2(FDKaacEnc_mTab_3_4[tabIndex],FDKaacEnc_quantTableE[totalShift&3]);
 141       totalShift = (16-4)-(3*(totalShift>>2));
 142       FDK_ASSERT(totalShift >=0); /* MAX_QUANT_VIOLATION */
 143       accu >>= fixMin(totalShift,DFRACT_BITS-1);
 144       quaSpectrum[line] = (SHORT)((LONG)(k + accu) >> (DFRACT_BITS-1-16));
 145     }
 146     else
 147       quaSpectrum[line]=0;
 148   }
 149 }
 150
 151
 152 /*****************************************************************************
 153
 154     functionname:iFDKaacEnc_quantizeLines
 155     description: iquantizes spectrum lines
 156                  mdctSpectrum = iquaSpectrum^4/3 *2^(0.25*gain)
 157     input: global gain, number of lines to process,quantized spectrum
 158     output: spectral data
 159
 160 *****************************************************************************/
 161 static void FDKaacEnc_invQuantizeLines(INT  gain,
 162                              INT  noOfLines,
 163                              SHORT *quantSpectrum,
 164                              FIXP_DBL *mdctSpectrum)
 165
 166 {
 167   INT iquantizermod;
 168   INT iquantizershift;
 169   INT line;
 170
 171   iquantizermod = gain&3;
 172   iquantizershift = gain>>2;
 173
 174   for (line = 0; line < noOfLines; line++) {
 175
 176     if(quantSpectrum[line] < 0) {
 177       FIXP_DBL accu;
 178       INT ex,specExp,tabIndex;
 179       FIXP_DBL s,t;
 180
 181       accu = (FIXP_DBL) -quantSpectrum[line];
 182
 183       ex = CountLeadingBits(accu);
 184       accu <<= ex;
 185       specExp = (DFRACT_BITS-1) - ex;
 186
 187       FDK_ASSERT(specExp < 14);       /* this fails if abs(value) > 8191 */
 188
 189       tabIndex = (INT)(accu>>(DFRACT_BITS-2-MANT_DIGITS))&(~MANT_SIZE);
 190
 191       /* calculate "mantissa" ^4/3 */
 192       s = FDKaacEnc_mTab_4_3Elc[tabIndex];
 193
 194       /* get approperiate exponent multiplier for specExp^3/4 combined with scfMod */
 195       t = FDKaacEnc_specExpMantTableCombElc[iquantizermod][specExp];
 196
 197       /* multiply "mantissa" ^4/3 with exponent multiplier */
 198       accu = fMult(s,t);
 199
 200       /* get approperiate exponent shifter */
 201       specExp = FDKaacEnc_specExpTableComb[iquantizermod][specExp]-1; /* -1 to avoid overflows in accu */
 202
 203       if ((-iquantizershift-specExp) < 0)
 204         accu <<= -(-iquantizershift-specExp);
 205       else
 206         accu >>= -iquantizershift-specExp;
 207
 208       mdctSpectrum[line] = -accu;
 209     }
 210     else if (quantSpectrum[line] > 0) {
 211       FIXP_DBL accu;
 212       INT ex,specExp,tabIndex;
 213       FIXP_DBL s,t;
 214
 215       accu = (FIXP_DBL)(INT)quantSpectrum[line];
 216
 217       ex = CountLeadingBits(accu);
 218       accu <<= ex;
 219       specExp = (DFRACT_BITS-1) - ex;
 220
 221       FDK_ASSERT(specExp < 14);       /* this fails if abs(value) > 8191 */
 222
 223       tabIndex = (INT)(accu>>(DFRACT_BITS-2-MANT_DIGITS))&(~MANT_SIZE);
 224
 225       /* calculate "mantissa" ^4/3 */
 226       s = FDKaacEnc_mTab_4_3Elc[tabIndex];
 227
 228       /* get approperiate exponent multiplier for specExp^3/4 combined with scfMod */
 229       t = FDKaacEnc_specExpMantTableCombElc[iquantizermod][specExp];
 230
 231       /* multiply "mantissa" ^4/3 with exponent multiplier */
 232       accu = fMult(s,t);
 233
 234       /* get approperiate exponent shifter */
 235       specExp = FDKaacEnc_specExpTableComb[iquantizermod][specExp]-1; /* -1 to avoid overflows in accu */
 236
 237       if (( -iquantizershift-specExp) < 0)
 238         accu <<= -(-iquantizershift-specExp);
 239       else
 240         accu >>= -iquantizershift-specExp;
 241
 242       mdctSpectrum[line] = accu;
 243     }
 244     else {
 245       mdctSpectrum[line] = FL2FXCONST_DBL(0.0f);
 246     }
 247   }
 248 }
 249
 250 /*****************************************************************************
 251
 252     functionname: FDKaacEnc_QuantizeSpectrum
 253     description: quantizes the entire spectrum
 254     returns:
 255     input: number of scalefactor bands to be quantized, ...
 256     output: quantized spectrum
 257
 258 *****************************************************************************/
 259 void FDKaacEnc_QuantizeSpectrum(INT sfbCnt,
 260                       INT maxSfbPerGroup,
 261                       INT sfbPerGroup,
 262                       INT *sfbOffset,
 263                       FIXP_DBL *mdctSpectrum,
 264                       INT globalGain,
 265                       INT *scalefactors,
 266                       SHORT *quantizedSpectrum)
 267 {
 268   INT sfbOffs,sfb;
 269
 270   /* in FDKaacEnc_quantizeLines quaSpectrum is calculated with:
 271         spec^(3/4) * 2^(-3/16*QSS) * 2^(3/4*scale) + k
 272      simplify scaling calculation and reduce QSS before:
 273         spec^(3/4) * 2^(-3/16*(QSS - 4*scale)) */
 274
 275   for(sfbOffs=0;sfbOffs<sfbCnt;sfbOffs+=sfbPerGroup)
 276   for (sfb = 0; sfb < maxSfbPerGroup; sfb++)
 277   {
 278     INT scalefactor = scalefactors[sfbOffs+sfb] ;
 279
 280     FDKaacEnc_quantizeLines(globalGain - scalefactor, /* QSS */
 281                   sfbOffset[sfbOffs+sfb+1] - sfbOffset[sfbOffs+sfb],
 282                   mdctSpectrum + sfbOffset[sfbOffs+sfb],
 283                   quantizedSpectrum + sfbOffset[sfbOffs+sfb]);
 284   }
 285 }
 286
 287 /*****************************************************************************
 288
 289     functionname: FDKaacEnc_calcSfbDist
 290     description: calculates distortion of quantized values
 291     returns: distortion
 292     input: gain, number of lines to process, spectral data
 293     output:
 294
 295 *****************************************************************************/
 296 FIXP_DBL FDKaacEnc_calcSfbDist(FIXP_DBL *mdctSpectrum,
 297                      SHORT *quantSpectrum,
 298                      INT noOfLines,
 299                      INT gain
 300                      )
 301 {
 302   INT i,scale;
 303   FIXP_DBL xfsf;
 304   FIXP_DBL diff;
 305   FIXP_DBL invQuantSpec;
 306
 307   xfsf = FL2FXCONST_DBL(0.0f);
 308
 309   for (i=0; i<noOfLines; i++) {
 310     /* quantization */
 311     FDKaacEnc_quantizeLines(gain,
 312                   1,
 313                  &mdctSpectrum[i],
 314                  &quantSpectrum[i]);
 315
 316     if (fAbs(quantSpectrum[i])>MAX_QUANT) {
 317       return FL2FXCONST_DBL(0.0f);
 318     }
 319     /* inverse quantization */
 320     FDKaacEnc_invQuantizeLines(gain,1,&quantSpectrum[i],&invQuantSpec);
 321
 322     /* dist */
 323     diff = fixp_abs(fixp_abs(invQuantSpec) - fixp_abs(mdctSpectrum[i]>>1));
 324
 325     scale = CountLeadingBits(diff);
 326     diff = scaleValue(diff, scale);
 327     diff = fPow2(diff);
 328     scale = fixMin(2*(scale-1), DFRACT_BITS-1);
 329
 330     diff = scaleValue(diff, -scale);
 331
 332     xfsf = xfsf + diff;
 333   }
 334
 335   xfsf = CalcLdData(xfsf);
 336
 337   return xfsf;
 338 }
 339
 340 /*****************************************************************************
 341
 342     functionname: FDKaacEnc_calcSfbQuantEnergyAndDist
 343     description: calculates energy and distortion of quantized values
 344     returns:
 345     input: gain, number of lines to process, quantized spectral data,
 346            spectral data
 347     output: energy, distortion
 348
 349 *****************************************************************************/
 350 void FDKaacEnc_calcSfbQuantEnergyAndDist(FIXP_DBL *mdctSpectrum,
 351                                SHORT *quantSpectrum,
 352                                INT noOfLines,
 353                                INT gain,
 354                                FIXP_DBL *en,
 355                                FIXP_DBL *dist)
 356 {
 357   INT i,scale;
 358   FIXP_DBL invQuantSpec;
 359   FIXP_DBL diff;
 360
 361   FIXP_DBL energy = FL2FXCONST_DBL(0.0f);
 362   FIXP_DBL distortion = FL2FXCONST_DBL(0.0f);
 363
 364   for (i=0; i<noOfLines; i++) {
 365
 366     if (fAbs(quantSpectrum[i])>MAX_QUANT) {
 367       *en   = FL2FXCONST_DBL(0.0f);
 368       *dist = FL2FXCONST_DBL(0.0f);
 369       return;
 370     }
 371
 372     /* inverse quantization */
 373     FDKaacEnc_invQuantizeLines(gain,1,&quantSpectrum[i],&invQuantSpec);
 374
 375     /* energy */
 376     energy += fPow2(invQuantSpec);
 377
 378     /* dist */
 379     diff = fixp_abs(fixp_abs(invQuantSpec) - fixp_abs(mdctSpectrum[i]>>1));
 380
 381     scale = CountLeadingBits(diff);
 382     diff = scaleValue(diff, scale);
 383     diff = fPow2(diff);
 384
 385     scale = fixMin(2*(scale-1), DFRACT_BITS-1);
 386
 387     diff = scaleValue(diff, -scale);
 388
 389     distortion += diff;
 390   }
 391
 392   *en   = CalcLdData(energy)+FL2FXCONST_DBL(0.03125f);
 393   *dist = CalcLdData(distortion);
 394 }
 395