libFDK/src/autocorr2nd.cpp

   1
   2 /* -----------------------------------------------------------------------------------------------------------
   3 Software License for The Fraunhofer FDK AAC Codec Library for Android
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  10 the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio.
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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 /***************************  Fraunhofer IIS FDK Tools  ***********************
  85
  86    Author(s):   M. Lohwasser
  87    Description: auto-correlation functions
  88
  89 ******************************************************************************/
  90
  91 #include "autocorr2nd.h"
  92
  93
  94
  95 /*  If the accumulator does not provide enough overflow bits,
  96     products have to be shifted down in the autocorrelation below. */
  97 #define SHIFT_FACTOR (5)
  98 #define SHIFT >> (SHIFT_FACTOR)
  99
 100
 101 #if defined(__CC_ARM) || defined(__arm__)
 102 #include "arm/autocorr2nd.cpp"
 103 #endif
 104
 105
 106 /*!
 107  *
 108  * \brief Calculate second order autocorrelation using 2 accumulators
 109  *
 110  */
 111 #if !defined(FUNCTION_autoCorr2nd_real)
 112 INT
 113 autoCorr2nd_real (ACORR_COEFS *ac,          /*!< Pointer to autocorrelation coeffs */
 114                   const FIXP_DBL *reBuffer, /*!< Pointer to to real part of input samples */
 115                   const int len             /*!< Number input samples */
 116                  )
 117 {
 118   int   j, autoCorrScaling, mScale;
 119
 120   FIXP_DBL accu1, accu2, accu3, accu4, accu5;
 121
 122   const FIXP_DBL *pReBuf;
 123
 124   const FIXP_DBL *realBuf = reBuffer;
 125
 126   /*
 127     r11r,r22r
 128     r01r,r12r
 129     r02r
 130   */
 131   pReBuf = realBuf-2;
 132   accu5 = ( (fMultDiv2(pReBuf[0], pReBuf[2]) +
 133              fMultDiv2(pReBuf[1], pReBuf[3])) SHIFT);
 134   pReBuf++;
 135
 136   //len must be even
 137   accu1 = fPow2Div2(pReBuf[0]) SHIFT;
 138   accu3 = fMultDiv2(pReBuf[0], pReBuf[1]) SHIFT;
 139   pReBuf++;
 140
 141   for ( j = (len - 2)>>1; j != 0; j--,pReBuf+=2 ) {
 142
 143     accu1 += ( (fPow2Div2(pReBuf[0]) +
 144                 fPow2Div2(pReBuf[1])) SHIFT);
 145
 146     accu3 += ( (fMultDiv2(pReBuf[0], pReBuf[1]) +
 147                 fMultDiv2(pReBuf[1], pReBuf[2])) SHIFT);
 148
 149     accu5 += ( (fMultDiv2(pReBuf[0], pReBuf[2]) +
 150                 fMultDiv2(pReBuf[1], pReBuf[3])) SHIFT);
 151
 152   }
 153
 154   accu2 = (fPow2Div2(realBuf[-2]) SHIFT);
 155   accu2 += accu1;
 156
 157   accu1 += (fPow2Div2(realBuf[len - 2]) SHIFT);
 158
 159   accu4  = (fMultDiv2(realBuf[-1],realBuf[-2]) SHIFT);
 160   accu4 += accu3;
 161
 162   accu3 += (fMultDiv2(realBuf[len - 1],realBuf[len - 2]) SHIFT);
 163
 164   mScale = CntLeadingZeros( (accu1 | accu2 | fAbs(accu3) | fAbs(accu4) | fAbs(accu5)) ) - 1;
 165   autoCorrScaling = mScale - 1 - SHIFT_FACTOR; /* -1 because of fMultDiv2*/
 166
 167   /* Scale to common scale factor */
 168   ac->r11r = accu1 << mScale;
 169   ac->r22r = accu2 << mScale;
 170   ac->r01r = accu3 << mScale;
 171   ac->r12r = accu4 << mScale;
 172   ac->r02r = accu5 << mScale;
 173
 174   ac->det = (fMultDiv2(ac->r11r,ac->r22r) - fMultDiv2(ac->r12r,ac->r12r)) ;
 175   mScale  = CountLeadingBits(fAbs(ac->det));
 176
 177   ac->det     <<= mScale;
 178   ac->det_scale = mScale - 1;
 179
 180   return autoCorrScaling;
 181 }
 182 #endif
 183
 184 #ifndef LOW_POWER_SBR_ONLY
 185 #if !defined(FUNCTION_autoCorr2nd_cplx)
 186 INT
 187 autoCorr2nd_cplx (ACORR_COEFS *ac,           /*!< Pointer to autocorrelation coeffs */
 188                   const FIXP_DBL *reBuffer,  /*!< Pointer to real part of input samples */
 189                   const FIXP_DBL *imBuffer,  /*!< Pointer to imag part of input samples */
 190                   const int len              /*!< Number of input samples */
 191                  )
 192 {
 193
 194   int   j, autoCorrScaling, mScale, len_scale;
 195
 196   FIXP_DBL accu0, accu1,accu2, accu3, accu4, accu5, accu6, accu7, accu8;
 197
 198   const FIXP_DBL *pReBuf, *pImBuf;
 199
 200   const FIXP_DBL *realBuf = reBuffer;
 201   const FIXP_DBL *imagBuf = imBuffer;
 202
 203   (len>64) ? (len_scale = 6) : (len_scale = 5);
 204   /*
 205     r00r,
 206     r11r,r22r
 207     r01r,r12r
 208     r01i,r12i
 209     r02r,r02i
 210   */
 211   accu1 = accu3 = accu5 = accu7 = accu8 = FL2FXCONST_DBL(0.0f);
 212
 213   pReBuf  = realBuf-2, pImBuf  = imagBuf-2;
 214   accu7 += ( (fMultDiv2(pReBuf[2], pReBuf[0]) + fMultDiv2(pImBuf[2], pImBuf[0])) >> len_scale);
 215   accu8 += ( (fMultDiv2(pImBuf[2], pReBuf[0]) - fMultDiv2(pReBuf[2], pImBuf[0])) >> len_scale);
 216
 217   pReBuf = realBuf-1, pImBuf = imagBuf-1;
 218   for ( j = (len - 1); j != 0; j--,pReBuf++,pImBuf++ ){
 219     accu1 += ( (fPow2Div2(pReBuf[0]           ) + fPow2Div2(pImBuf[0]           )) >> len_scale);
 220     accu3 += ( (fMultDiv2(pReBuf[0], pReBuf[1]) + fMultDiv2(pImBuf[0], pImBuf[1])) >> len_scale);
 221     accu5 += ( (fMultDiv2(pImBuf[1], pReBuf[0]) - fMultDiv2(pReBuf[1], pImBuf[0])) >> len_scale);
 222     accu7 += ( (fMultDiv2(pReBuf[2], pReBuf[0]) + fMultDiv2(pImBuf[2], pImBuf[0])) >> len_scale);
 223     accu8 += ( (fMultDiv2(pImBuf[2], pReBuf[0]) - fMultDiv2(pReBuf[2], pImBuf[0])) >> len_scale);
 224   }
 225
 226   accu2 = ( (fPow2Div2(realBuf[-2]) + fPow2Div2(imagBuf[-2])) >> len_scale);
 227   accu2 += accu1;
 228
 229   accu1 += ( (fPow2Div2(realBuf[len-2]) +
 230               fPow2Div2(imagBuf[len-2])) >> len_scale);
 231   accu0 = ( (fPow2Div2(realBuf[len-1]) +
 232              fPow2Div2(imagBuf[len-1])) >> len_scale) -
 233           ( (fPow2Div2(realBuf[-1]) +
 234              fPow2Div2(imagBuf[-1])) >> len_scale);
 235   accu0 += accu1;
 236
 237   accu4 = ( (fMultDiv2(realBuf[-1], realBuf[-2]) +
 238              fMultDiv2(imagBuf[-1], imagBuf[-2])) >> len_scale);
 239   accu4 += accu3;
 240
 241   accu3 += ( (fMultDiv2(realBuf[len-1], realBuf[len-2]) +
 242               fMultDiv2(imagBuf[len-1], imagBuf[len-2])) >> len_scale);
 243
 244   accu6 = ( (fMultDiv2(imagBuf[-1], realBuf[-2]) -
 245              fMultDiv2(realBuf[-1], imagBuf[-2])) >> len_scale);
 246   accu6 += accu5;
 247
 248   accu5 += ( (fMultDiv2(imagBuf[len - 1], realBuf[len - 2]) -
 249               fMultDiv2(realBuf[len - 1], imagBuf[len - 2])) >> len_scale);
 250
 251   mScale = CntLeadingZeros( (accu0 | accu1 | accu2 | fAbs(accu3) | fAbs(accu4) | fAbs(accu5) |
 252                              fAbs(accu6) | fAbs(accu7) | fAbs(accu8)) ) - 1;
 253   autoCorrScaling = mScale - 1 - len_scale; /* -1 because of fMultDiv2*/
 254
 255   /* Scale to common scale factor */
 256   ac->r00r = (FIXP_DBL)accu0 << mScale;
 257   ac->r11r = (FIXP_DBL)accu1 << mScale;
 258   ac->r22r = (FIXP_DBL)accu2 << mScale;
 259   ac->r01r = (FIXP_DBL)accu3 << mScale;
 260   ac->r12r = (FIXP_DBL)accu4 << mScale;
 261   ac->r01i = (FIXP_DBL)accu5 << mScale;
 262   ac->r12i = (FIXP_DBL)accu6 << mScale;
 263   ac->r02r = (FIXP_DBL)accu7 << mScale;
 264   ac->r02i = (FIXP_DBL)accu8 << mScale;
 265
 266   ac->det = ( fMultDiv2(ac->r11r,ac->r22r) >> 1 ) -
 267             ( (fMultDiv2(ac->r12r,ac->r12r) + fMultDiv2(ac->r12i,ac->r12i)) >> 1 );
 268   mScale = CountLeadingBits(fAbs(ac->det));
 269
 270   ac->det <<= mScale;
 271   ac->det_scale = mScale - 2;
 272
 273   return autoCorrScaling;
 274 }
 275 #endif /* FUNCTION_autoCorr2nd_cplx */
 276 #endif /* LOW_POWER_SBR_ONLY */
 277
 278