libFDK/src/autocorr2nd.cpp

/* -----------------------------------------------------------------------------------------------------------
Software License for The Fraunhofer FDK AAC Codec Library for Android

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  All rights reserved.

 1.    INTRODUCTION
The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements
the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio.
This FDK AAC Codec software is intended to be used on a wide variety of Android devices.

AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual
audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by
independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part
of the MPEG specifications.

Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer)
may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners
individually for the purpose of encoding or decoding bit streams in products that are compliant with
the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license
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software may already be covered under those patent licenses when it is used for those licensed purposes only.

Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality,
are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional
applications information and documentation.

2.    COPYRIGHT LICENSE

Redistribution and use in source and binary forms, with or without modification, are permitted without
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This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright holders and contributors
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5.    CONTACT INFORMATION

Fraunhofer Institute for Integrated Circuits IIS
Attention: Audio and Multimedia Departments - FDK AAC LL
Am Wolfsmantel 33
91058 Erlangen, Germany

www.iis.fraunhofer.de/amm
amm-info@iis.fraunhofer.de
----------------------------------------------------------------------------------------------------------- */

/***************************  Fraunhofer IIS FDK Tools  ***********************

   Author(s):   M. Lohwasser
   Description: auto-correlation functions

******************************************************************************/

#include "autocorr2nd.h"



/*  If the accumulator does not provide enough overflow bits,
    products have to be shifted down in the autocorrelation below. */
#define SHIFT_FACTOR (5)
#define SHIFT >> (SHIFT_FACTOR)


#if defined(__CC_ARM) || defined(__arm__)
#include "arm/autocorr2nd.cpp"
#endif


/*!
 *
 * \brief Calculate second order autocorrelation using 2 accumulators
 *
 */
#if !defined(FUNCTION_autoCorr2nd_real)
INT
autoCorr2nd_real (ACORR_COEFS *ac,          /*!< Pointer to autocorrelation coeffs */
                  const FIXP_DBL *reBuffer, /*!< Pointer to to real part of input samples */
                  const int len             /*!< Number input samples */
                 )
{
  int   j, autoCorrScaling, mScale;

  FIXP_DBL accu1, accu2, accu3, accu4, accu5;

  const FIXP_DBL *pReBuf;

  const FIXP_DBL *realBuf = reBuffer;

  /*
    r11r,r22r
    r01r,r12r
    r02r
  */
  pReBuf = realBuf-2;
  accu5 = ( (fMultDiv2(pReBuf[0], pReBuf[2]) +
             fMultDiv2(pReBuf[1], pReBuf[3])) SHIFT);
  pReBuf++;

  //len must be even
  accu1 = fPow2Div2(pReBuf[0]) SHIFT;
  accu3 = fMultDiv2(pReBuf[0], pReBuf[1]) SHIFT;
  pReBuf++;

  for ( j = (len - 2)>>1; j != 0; j--,pReBuf+=2 ) {

    accu1 += ( (fPow2Div2(pReBuf[0]) +
                fPow2Div2(pReBuf[1])) SHIFT);

    accu3 += ( (fMultDiv2(pReBuf[0], pReBuf[1]) +
                fMultDiv2(pReBuf[1], pReBuf[2])) SHIFT);

    accu5 += ( (fMultDiv2(pReBuf[0], pReBuf[2]) +
                fMultDiv2(pReBuf[1], pReBuf[3])) SHIFT);

  }

  accu2 = (fPow2Div2(realBuf[-2]) SHIFT);
  accu2 += accu1;

  accu1 += (fPow2Div2(realBuf[len - 2]) SHIFT);

  accu4  = (fMultDiv2(realBuf[-1],realBuf[-2]) SHIFT);
  accu4 += accu3;

  accu3 += (fMultDiv2(realBuf[len - 1],realBuf[len - 2]) SHIFT);

  mScale = CntLeadingZeros( (accu1 | accu2 | fAbs(accu3) | fAbs(accu4) | fAbs(accu5)) ) - 1;
  autoCorrScaling = mScale - 1 - SHIFT_FACTOR; /* -1 because of fMultDiv2*/

  /* Scale to common scale factor */
  ac->r11r = accu1 << mScale;
  ac->r22r = accu2 << mScale;
  ac->r01r = accu3 << mScale;
  ac->r12r = accu4 << mScale;
  ac->r02r = accu5 << mScale;

  ac->det = (fMultDiv2(ac->r11r,ac->r22r) - fMultDiv2(ac->r12r,ac->r12r)) ;
  mScale  = CountLeadingBits(fAbs(ac->det));

  ac->det     <<= mScale;
  ac->det_scale = mScale - 1;

  return autoCorrScaling;
}
#endif

#ifndef LOW_POWER_SBR_ONLY
#if !defined(FUNCTION_autoCorr2nd_cplx)
INT
autoCorr2nd_cplx (ACORR_COEFS *ac,           /*!< Pointer to autocorrelation coeffs */
                  const FIXP_DBL *reBuffer,  /*!< Pointer to real part of input samples */
                  const FIXP_DBL *imBuffer,  /*!< Pointer to imag part of input samples */
                  const int len              /*!< Number of input samples */
                 )
{

  int   j, autoCorrScaling, mScale, len_scale;

  FIXP_DBL accu0, accu1,accu2, accu3, accu4, accu5, accu6, accu7, accu8;

  const FIXP_DBL *pReBuf, *pImBuf;

  const FIXP_DBL *realBuf = reBuffer;
  const FIXP_DBL *imagBuf = imBuffer;

  (len>64) ? (len_scale = 6) : (len_scale = 5);
  /*
    r00r,
    r11r,r22r
    r01r,r12r
    r01i,r12i
    r02r,r02i
  */
  accu1 = accu3 = accu5 = accu7 = accu8 = FL2FXCONST_DBL(0.0f);

  pReBuf  = realBuf-2, pImBuf  = imagBuf-2;
  accu7 += ( (fMultDiv2(pReBuf[2], pReBuf[0]) + fMultDiv2(pImBuf[2], pImBuf[0])) >> len_scale);
  accu8 += ( (fMultDiv2(pImBuf[2], pReBuf[0]) - fMultDiv2(pReBuf[2], pImBuf[0])) >> len_scale);

  pReBuf = realBuf-1, pImBuf = imagBuf-1;
  for ( j = (len - 1); j != 0; j--,pReBuf++,pImBuf++ ){
    accu1 += ( (fPow2Div2(pReBuf[0]           ) + fPow2Div2(pImBuf[0]           )) >> len_scale);
    accu3 += ( (fMultDiv2(pReBuf[0], pReBuf[1]) + fMultDiv2(pImBuf[0], pImBuf[1])) >> len_scale);
    accu5 += ( (fMultDiv2(pImBuf[1], pReBuf[0]) - fMultDiv2(pReBuf[1], pImBuf[0])) >> len_scale);
    accu7 += ( (fMultDiv2(pReBuf[2], pReBuf[0]) + fMultDiv2(pImBuf[2], pImBuf[0])) >> len_scale);
    accu8 += ( (fMultDiv2(pImBuf[2], pReBuf[0]) - fMultDiv2(pReBuf[2], pImBuf[0])) >> len_scale);
  }

  accu2 = ( (fPow2Div2(realBuf[-2]) + fPow2Div2(imagBuf[-2])) >> len_scale);
  accu2 += accu1;

  accu1 += ( (fPow2Div2(realBuf[len-2]) +
              fPow2Div2(imagBuf[len-2])) >> len_scale);
  accu0 = ( (fPow2Div2(realBuf[len-1]) +
             fPow2Div2(imagBuf[len-1])) >> len_scale) -
          ( (fPow2Div2(realBuf[-1]) +
             fPow2Div2(imagBuf[-1])) >> len_scale);
  accu0 += accu1;

  accu4 = ( (fMultDiv2(realBuf[-1], realBuf[-2]) +
             fMultDiv2(imagBuf[-1], imagBuf[-2])) >> len_scale);
  accu4 += accu3;

  accu3 += ( (fMultDiv2(realBuf[len-1], realBuf[len-2]) +
              fMultDiv2(imagBuf[len-1], imagBuf[len-2])) >> len_scale);

  accu6 = ( (fMultDiv2(imagBuf[-1], realBuf[-2]) -
             fMultDiv2(realBuf[-1], imagBuf[-2])) >> len_scale);
  accu6 += accu5;

  accu5 += ( (fMultDiv2(imagBuf[len - 1], realBuf[len - 2]) -
              fMultDiv2(realBuf[len - 1], imagBuf[len - 2])) >> len_scale);

  mScale = CntLeadingZeros( (accu0 | accu1 | accu2 | fAbs(accu3) | fAbs(accu4) | fAbs(accu5) |
                             fAbs(accu6) | fAbs(accu7) | fAbs(accu8)) ) - 1;
  autoCorrScaling = mScale - 1 - len_scale; /* -1 because of fMultDiv2*/

  /* Scale to common scale factor */
  ac->r00r = (FIXP_DBL)accu0 << mScale;
  ac->r11r = (FIXP_DBL)accu1 << mScale;
  ac->r22r = (FIXP_DBL)accu2 << mScale;
  ac->r01r = (FIXP_DBL)accu3 << mScale;
  ac->r12r = (FIXP_DBL)accu4 << mScale;
  ac->r01i = (FIXP_DBL)accu5 << mScale;
  ac->r12i = (FIXP_DBL)accu6 << mScale;
  ac->r02r = (FIXP_DBL)accu7 << mScale;
  ac->r02i = (FIXP_DBL)accu8 << mScale;

  ac->det = ( fMultDiv2(ac->r11r,ac->r22r) >> 1 ) -
            ( (fMultDiv2(ac->r12r,ac->r12r) + fMultDiv2(ac->r12i,ac->r12i)) >> 1 );
  mScale = CountLeadingBits(fAbs(ac->det));

  ac->det <<= mScale;
  ac->det_scale = mScale - 2;

  return autoCorrScaling;
}
#endif /* FUNCTION_autoCorr2nd_cplx */
#endif /* LOW_POWER_SBR_ONLY */