libAACenc/src/tonality.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.
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  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
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  16 of the MPEG specifications.
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  73 5.    CONTACT INFORMATION
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  75 Fraunhofer Institute for Integrated Circuits IIS
  76 Attention: Audio and Multimedia Departments - FDK AAC LL
  77 Am Wolfsmantel 33
  78 91058 Erlangen, Germany
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  80 www.iis.fraunhofer.de/amm
  81 amm-info@iis.fraunhofer.de
  82 ----------------------------------------------------------------------------------------------------------- */
  83
  84 /******************************** MPEG Audio Encoder **************************
  85
  86    author:   M. Werner
  87    contents/description: Convert chaos measure to the tonality index
  88
  89 ******************************************************************************/
  90
  91 #include "tonality.h"
  92 #include "chaosmeasure.h"
  93
  94 static const FIXP_DBL normlog = (FIXP_DBL)0xd977d949; /*FL2FXCONST_DBL(-0.4342944819f * FDKlog(2.0)/FDKlog(2.7182818)); */
  95
  96 static void FDKaacEnc_CalcSfbTonality(FIXP_DBL      *RESTRICT spectrum,
  97                                                         INT           *RESTRICT sfbMaxScaleSpec,
  98                             FIXP_DBL      *RESTRICT chaosMeasure,
  99                             FIXP_SGL      *RESTRICT sfbTonality,
 100                             INT           sfbCnt,
 101                             const INT     *RESTRICT sfbOffset,
 102                             FIXP_DBL      *RESTRICT sfbEnergyLD64 );
 103
 104
 105 void FDKaacEnc_CalculateFullTonality(FIXP_DBL      *RESTRICT spectrum,
 106                                                              INT           *RESTRICT sfbMaxScaleSpec,
 107                                      FIXP_DBL      *RESTRICT sfbEnergyLD64,
 108                                      FIXP_SGL      *RESTRICT sfbTonality,
 109                                      INT            sfbCnt,
 110                                      const INT     *sfbOffset,
 111                                      INT            usePns)
 112 {
 113   INT j;
 114 #if defined(ARCH_PREFER_MULT_32x16)
 115   FIXP_SGL alpha_0 = FL2FXCONST_SGL(0.25f);       /* used in smooth ChaosMeasure */
 116   FIXP_SGL alpha_1 = FL2FXCONST_SGL(1.0f-0.25f);  /* used in smooth ChaosMeasure */
 117 #else
 118   FIXP_DBL alpha_0 = FL2FXCONST_DBL(0.25f);       /* used in smooth ChaosMeasure */
 119   FIXP_DBL alpha_1 = FL2FXCONST_DBL(1.0f-0.25f);  /* used in smooth ChaosMeasure */
 120 #endif
 121   INT numberOfLines = sfbOffset[sfbCnt];
 122
 123   if (!usePns)
 124     return;
 125
 126   C_ALLOC_SCRATCH_START(chaosMeasurePerLine, FIXP_DBL, (1024));
 127   /* calculate chaos measure */
 128   FDKaacEnc_CalculateChaosMeasure(spectrum,
 129                         numberOfLines,
 130                         chaosMeasurePerLine);
 131
 132   /* smooth ChaosMeasure */
 133   for (j=1;j<numberOfLines;j++) {
 134     FIXP_DBL tmp = fMultDiv2(alpha_1, chaosMeasurePerLine[j]);
 135     chaosMeasurePerLine[j] = fMultAdd(tmp, alpha_0, chaosMeasurePerLine[j-1]);
 136   }
 137
 138   FDKaacEnc_CalcSfbTonality(spectrum,
 139                   sfbMaxScaleSpec,
 140                   chaosMeasurePerLine,
 141                   sfbTonality,
 142                   sfbCnt,
 143                   sfbOffset,
 144                   sfbEnergyLD64);
 145
 146   C_ALLOC_SCRATCH_END(chaosMeasurePerLine, FIXP_DBL, (1024));
 147 }
 148
 149
 150 /*****************************************************************************
 151
 152     functionname: CalculateTonalityIndex
 153     description:  computes tonality values out of unpredictability values
 154                   limits range and computes log()
 155     returns:
 156     input:        ptr to energies, ptr to chaos measure values,
 157                   number of sfb
 158     output:       sfb wise tonality values
 159
 160 *****************************************************************************/
 161 static void FDKaacEnc_CalcSfbTonality(FIXP_DBL      *RESTRICT spectrum,
 162                             INT           *RESTRICT sfbMaxScaleSpec,
 163                             FIXP_DBL      *RESTRICT chaosMeasure,
 164                             FIXP_SGL      *RESTRICT sfbTonality,
 165                             INT           sfbCnt,
 166                             const INT     *RESTRICT sfbOffset,
 167                             FIXP_DBL      *RESTRICT sfbEnergyLD64 )
 168 {
 169     INT i, j;
 170
 171     for (i=0; i<sfbCnt; i++) {
 172       FIXP_DBL chaosMeasureSfbLD64;
 173       INT shiftBits = fixMax(0,sfbMaxScaleSpec[i] - 4);  /* max sfbWidth = 96 ; 2^7=128 => 7/2 = 4 (spc*spc) */
 174
 175       FIXP_DBL chaosMeasureSfb = FL2FXCONST_DBL(0.0);
 176
 177       /* calc chaosMeasurePerSfb */
 178       for (j=(sfbOffset[i+1]-sfbOffset[i])-1; j>=0; j--) {
 179         FIXP_DBL tmp = (*spectrum++)<<shiftBits;
 180         FIXP_DBL lineNrg = fMultDiv2(tmp, tmp);
 181         chaosMeasureSfb = fMultAddDiv2(chaosMeasureSfb, lineNrg, *chaosMeasure++);
 182       }
 183
 184       /* calc tonalityPerSfb */
 185       if (chaosMeasureSfb != FL2FXCONST_DBL(0.0))
 186       {
 187         /* add ld(convtone)/64 and 2/64 bec.fMultDiv2 */
 188         chaosMeasureSfbLD64 = CalcLdData((chaosMeasureSfb)) - sfbEnergyLD64[i];
 189         chaosMeasureSfbLD64 += FL2FXCONST_DBL(3.0f/64) - ((FIXP_DBL)(shiftBits)<<(DFRACT_BITS-6));
 190
 191         if (chaosMeasureSfbLD64 > FL2FXCONST_DBL(-0.0519051) )     /* > ld(0.05)+ld(2) */
 192         {
 193           if (chaosMeasureSfbLD64 <= FL2FXCONST_DBL(0.0) )
 194                     sfbTonality[i] = FX_DBL2FX_SGL(fMultDiv2( chaosMeasureSfbLD64 , normlog ) << 7);
 195           else
 196             sfbTonality[i] = FL2FXCONST_SGL(0.0);
 197         }
 198         else
 199           sfbTonality[i] = (FIXP_SGL)MAXVAL_SGL;
 200       }
 201       else
 202         sfbTonality[i] = (FIXP_SGL)MAXVAL_SGL;
 203     }
 204 }