libAACenc/src/ms_stereo.cpp

   1
   2 /* -----------------------------------------------------------------------------------------------------------
   3 Software License for The Fraunhofer FDK AAC Codec Library for Android
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   5 © Copyright  1995 - 2013 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
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   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.
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  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
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  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: MS stereo processing
  88
  89 ******************************************************************************/
  90 #include "ms_stereo.h"
  91
  92 #include "psy_const.h"
  93
  94 /* static const float scaleMinThres = 1.0f; */ /* 0.75f for 3db boost */
  95
  96 void FDKaacEnc_MsStereoProcessing(PSY_DATA   *RESTRICT psyData[(2)],
  97                         PSY_OUT_CHANNEL* psyOutChannel[2],
  98                         const INT  *isBook,
  99                         INT        *msDigest,       /* output */
 100                         INT        *msMask,         /* output */
 101                         const INT   sfbCnt,
 102                         const INT   sfbPerGroup,
 103                         const INT   maxSfbPerGroup,
 104                         const INT  *sfbOffset)
 105 {
 106     FIXP_DBL        *sfbEnergyLeft = psyData[0]->sfbEnergy.Long;                       /* modified where msMask==1 */
 107     FIXP_DBL        *sfbEnergyRight = psyData[1]->sfbEnergy.Long;                      /* modified where msMask==1 */
 108     const FIXP_DBL  *sfbEnergyMid = psyData[0]->sfbEnergyMS.Long;
 109     const FIXP_DBL  *sfbEnergySide = psyData[1]->sfbEnergyMS.Long;
 110     FIXP_DBL        *sfbThresholdLeft = psyData[0]->sfbThreshold.Long;                 /* modified where msMask==1 */
 111     FIXP_DBL        *sfbThresholdRight = psyData[1]->sfbThreshold.Long;                /* modified where msMask==1 */
 112
 113     FIXP_DBL        *sfbSpreadEnLeft = psyData[0]->sfbSpreadEnergy.Long;
 114     FIXP_DBL        *sfbSpreadEnRight = psyData[1]->sfbSpreadEnergy.Long;
 115
 116     FIXP_DBL        *sfbEnergyLeftLdData = psyOutChannel[0]->sfbEnergyLdData;        /* modified where msMask==1 */
 117     FIXP_DBL        *sfbEnergyRightLdData = psyOutChannel[1]->sfbEnergyLdData;       /* modified where msMask==1 */
 118     FIXP_DBL        *sfbEnergyMidLdData = psyData[0]->sfbEnergyMSLdData;
 119     FIXP_DBL        *sfbEnergySideLdData = psyData[1]->sfbEnergyMSLdData;
 120     FIXP_DBL        *sfbThresholdLeftLdData = psyOutChannel[0]->sfbThresholdLdData;  /* modified where msMask==1 */
 121     FIXP_DBL        *sfbThresholdRightLdData = psyOutChannel[1]->sfbThresholdLdData; /* modified where msMask==1 */
 122
 123     FIXP_DBL        *mdctSpectrumLeft = psyData[0]->mdctSpectrum;                      /* modified where msMask==1 */
 124     FIXP_DBL        *mdctSpectrumRight = psyData[1]->mdctSpectrum;                     /* modified where msMask==1 */
 125
 126     INT             sfb,sfboffs, j;           /* loop counters         */
 127     FIXP_DBL        pnlrLdData, pnmsLdData;
 128     FIXP_DBL        minThresholdLdData;
 129     FIXP_DBL        minThreshold;
 130     INT             useMS;
 131
 132     INT             msMaskTrueSomewhere = 0;  /* to determine msDigest */
 133     INT             numMsMaskFalse = 0;       /* number of non-intensity bands where L/R coding is used */
 134
 135     for(sfb=0; sfb<sfbCnt; sfb+=sfbPerGroup) {
 136       for(sfboffs=0;sfboffs<maxSfbPerGroup;sfboffs++) {
 137
 138         if ( (isBook==NULL) ? 1 : (isBook[sfb+sfboffs] == 0) ) {
 139           FIXP_DBL tmp;
 140
 141 /*
 142           minThreshold=min(sfbThresholdLeft[sfb+sfboffs], sfbThresholdRight[sfb+sfboffs])*scaleMinThres;
 143           pnlr = (sfbThresholdLeft[sfb+sfboffs]/
 144                  max(sfbEnergyLeft[sfb+sfboffs],sfbThresholdLeft[sfb+sfboffs]))*
 145                  (sfbThresholdRight[sfb+sfboffs]/
 146                  max(sfbEnergyRight[sfb+sfboffs],sfbThresholdRight[sfb+sfboffs]));
 147           pnms = (minThreshold/max(sfbEnergyMid[sfb+sfboffs],minThreshold))*
 148                  (minThreshold/max(sfbEnergySide[sfb+sfboffs],minThreshold));
 149           useMS = (pnms > pnlr);
 150 */
 151
 152           /* we assume that scaleMinThres == 1.0f and we can drop it */
 153           minThresholdLdData = fixMin(sfbThresholdLeftLdData[sfb+sfboffs], sfbThresholdRightLdData[sfb+sfboffs]);
 154
 155           /* pnlrLdData = sfbThresholdLeftLdData[sfb+sfboffs] -
 156                         max(sfbEnergyLeftLdData[sfb+sfboffs], sfbThresholdLeftLdData[sfb+sfboffs]) +
 157                         sfbThresholdRightLdData[sfb+sfboffs] -
 158                         max(sfbEnergyRightLdData[sfb+sfboffs], sfbThresholdRightLdData[sfb+sfboffs]); */
 159           tmp = fixMax(sfbEnergyLeftLdData[sfb+sfboffs], sfbThresholdLeftLdData[sfb+sfboffs]);
 160           pnlrLdData = (sfbThresholdLeftLdData[sfb+sfboffs]>>1) - (tmp>>1);
 161           pnlrLdData = pnlrLdData + (sfbThresholdRightLdData[sfb+sfboffs]>>1);
 162           tmp = fixMax(sfbEnergyRightLdData[sfb+sfboffs], sfbThresholdRightLdData[sfb+sfboffs]);
 163           pnlrLdData = pnlrLdData - (tmp>>1);
 164
 165           /* pnmsLdData = minThresholdLdData - max(sfbEnergyMidLdData[sfb+sfboffs], minThresholdLdData) +
 166                         minThresholdLdData - max(sfbEnergySideLdData[sfb+sfboffs], minThresholdLdData); */
 167           tmp = fixMax(sfbEnergyMidLdData[sfb+sfboffs], minThresholdLdData);
 168           pnmsLdData = minThresholdLdData - (tmp>>1);
 169           tmp = fixMax(sfbEnergySideLdData[sfb+sfboffs], minThresholdLdData);
 170           pnmsLdData = pnmsLdData - (tmp>>1);
 171           useMS = (pnmsLdData > (pnlrLdData));
 172
 173
 174           if (useMS) {
 175             msMask[sfb+sfboffs] = 1;
 176             msMaskTrueSomewhere = 1;
 177             for(j=sfbOffset[sfb+sfboffs]; j<sfbOffset[sfb+sfboffs+1]; j++) {
 178               FIXP_DBL specL, specR;
 179               specL = mdctSpectrumLeft[j]>>1;
 180               specR = mdctSpectrumRight[j]>>1;
 181               mdctSpectrumLeft[j] = specL + specR;
 182               mdctSpectrumRight[j] = specL - specR;
 183             }
 184             minThreshold = fixMin(sfbThresholdLeft[sfb+sfboffs], sfbThresholdRight[sfb+sfboffs]);
 185             sfbThresholdLeft[sfb+sfboffs] = sfbThresholdRight[sfb+sfboffs] = minThreshold;
 186             sfbThresholdLeftLdData[sfb+sfboffs] = sfbThresholdRightLdData[sfb+sfboffs] = minThresholdLdData;
 187             sfbEnergyLeft[sfb+sfboffs] = sfbEnergyMid[sfb+sfboffs];
 188             sfbEnergyRight[sfb+sfboffs] = sfbEnergySide[sfb+sfboffs];
 189             sfbEnergyLeftLdData[sfb+sfboffs] = sfbEnergyMidLdData[sfb+sfboffs];
 190             sfbEnergyRightLdData[sfb+sfboffs] = sfbEnergySideLdData[sfb+sfboffs];
 191
 192             sfbSpreadEnLeft[sfb+sfboffs] = sfbSpreadEnRight[sfb+sfboffs] =
 193                      fixMin( sfbSpreadEnLeft[sfb+sfboffs],
 194                              sfbSpreadEnRight[sfb+sfboffs] ) >> 1;
 195
 196           }
 197           else {
 198             msMask[sfb+sfboffs] = 0;
 199             numMsMaskFalse++;
 200           } /* useMS */
 201         } /* isBook */
 202         else {
 203           /* keep mDigest from IS module */
 204           if (msMask[sfb+sfboffs]) {
 205             msMaskTrueSomewhere = 1;
 206           }
 207           /* prohibit MS_MASK_ALL in combination with IS */
 208           numMsMaskFalse = 9;
 209         } /* isBook */
 210       } /* sfboffs */
 211     } /* sfb */
 212
 213
 214     if(msMaskTrueSomewhere == 1) {
 215       if ((numMsMaskFalse == 0) || ((numMsMaskFalse < maxSfbPerGroup) && (numMsMaskFalse < 9))) {
 216         *msDigest = SI_MS_MASK_ALL;
 217         /* loop through M/S bands; if msMask==0, set it to 1 and apply M/S */
 218         for (sfb = 0; sfb < sfbCnt; sfb += sfbPerGroup) {
 219           for (sfboffs = 0; sfboffs < maxSfbPerGroup; sfboffs++) {
 220             if (( (isBook == NULL) ? 1 : (isBook[sfb+sfboffs] == 0) ) && (msMask[sfb+sfboffs] == 0)) {
 221               msMask[sfb+sfboffs] = 1;
 222               /* apply M/S coding */
 223               for(j=sfbOffset[sfb+sfboffs]; j<sfbOffset[sfb+sfboffs+1]; j++) {
 224                 FIXP_DBL specL, specR;
 225                 specL = mdctSpectrumLeft[j]>>1;
 226                 specR = mdctSpectrumRight[j]>>1;
 227                 mdctSpectrumLeft[j] = specL + specR;
 228                 mdctSpectrumRight[j] = specL - specR;
 229               }
 230               minThreshold = fixMin(sfbThresholdLeft[sfb+sfboffs], sfbThresholdRight[sfb+sfboffs]);
 231               sfbThresholdLeft[sfb+sfboffs] = sfbThresholdRight[sfb+sfboffs] = minThreshold;
 232               minThresholdLdData = fixMin(sfbThresholdLeftLdData[sfb+sfboffs], sfbThresholdRightLdData[sfb+sfboffs]);
 233               sfbThresholdLeftLdData[sfb+sfboffs] = sfbThresholdRightLdData[sfb+sfboffs] = minThresholdLdData;
 234               sfbEnergyLeft[sfb+sfboffs] = sfbEnergyMid[sfb+sfboffs];
 235               sfbEnergyRight[sfb+sfboffs] = sfbEnergySide[sfb+sfboffs];
 236               sfbEnergyLeftLdData[sfb+sfboffs] = sfbEnergyMidLdData[sfb+sfboffs];
 237               sfbEnergyRightLdData[sfb+sfboffs] = sfbEnergySideLdData[sfb+sfboffs];
 238
 239               sfbSpreadEnLeft[sfb+sfboffs] = sfbSpreadEnRight[sfb+sfboffs] =
 240                        fixMin( sfbSpreadEnLeft[sfb+sfboffs],
 241                                sfbSpreadEnRight[sfb+sfboffs] ) >> 1;
 242             }
 243           }
 244         }
 245       } else {
 246         *msDigest = SI_MS_MASK_SOME;
 247       }
 248     } else {
 249       *msDigest = SI_MS_MASK_NONE;
 250     }
 251 }