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

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)
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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.

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Redistribution and use in source and binary forms, with or without modification, are permitted without
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You must retain the complete text of this software license in redistributions of the FDK AAC Codec or
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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
----------------------------------------------------------------------------------------------------------- */

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

Description: FDKaacLdEnc_MdctTransform480:
                The module FDKaacLdEnc_MdctTransform will perform the MDCT.
                The MDCT supports the sine window and
                the zero padded window. The algorithm of the MDCT
                can be divided in  Windowing, PreModulation, Fft and
                PostModulation.

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

#include "transform.h"

#include "dct.h"
#include "psy_const.h"
#include "aacEnc_rom.h"
#include "FDK_tools_rom.h"

INT FDKaacEnc_Transform_Real (const INT_PCM * pTimeData,
                              FIXP_DBL *RESTRICT mdctData,
                              const INT blockType,
                              const INT windowShape,
                              INT *prevWindowShape,
                              const INT frameLength,
                              INT *mdctData_e,
                              INT filterType
                             ,FIXP_DBL * RESTRICT overlapAddBuffer
                             )
{
  const INT_PCM * RESTRICT timeData;

INT i;
  /* tl: transform length
     fl: left window slope length
     nl: left window slope offset
     fr: right window slope length
     nr: right window slope offset
     See FDK_tools/doc/intern/mdct.tex for more detail. */
  int tl, fl, nl, fr, nr;

const FIXP_WTP * RESTRICT pLeftWindowPart;
  const FIXP_WTP * RESTRICT pRightWindowPart;

/*
   * MDCT scale:
   * + 1: fMultDiv2() in windowing.
   * + 1: Because of factor 1/2 in Princen-Bradley compliant windowed TDAC.
   */
  *mdctData_e = 1+1;

tl = frameLength;
  timeData = pTimeData;

switch( blockType ) {
    case LONG_WINDOW:
      {
        int offset = (windowShape == LOL_WINDOW) ? ((frameLength * 3)>>2) : 0;
        fl = frameLength - offset;
        fr = frameLength - offset;
      }
      break;
    case STOP_WINDOW:
      fl = frameLength >> 3;
      fr = frameLength;
      break;
    case START_WINDOW: /* or StopStartSequence */
      fl = frameLength;
      fr = frameLength >> 3;
      break;
    case SHORT_WINDOW:
      fl = fr = frameLength >> 3;
      tl >>= 3;
      timeData = pTimeData + 3*fl + (fl/2);
      break;
    default:
      FDK_ASSERT(0);
      return -1;
      break;
  }

/* Taken from FDK_tools/src/mdct.cpp Derive NR and NL */
  nr = (tl - fr)>>1;
  nl = (tl - fl)>>1;

pLeftWindowPart = FDKgetWindowSlope(fl, *prevWindowShape);
  pRightWindowPart = FDKgetWindowSlope(fr, windowShape);

/* windowing */
  if (filterType != FB_ELD)
  {
    /* Left window slope offset */
    for (i=0; i<nl ; i++)
    {
#if SAMPLE_BITS == DFRACT_BITS   /* SPC_BITS and DFRACT_BITS should be equal. */
      mdctData[(tl/2)+i] = - (FIXP_DBL) timeData[tl-i-1] >> ( 1 );
#else
      mdctData[(tl/2)+i] = - (FIXP_DBL) timeData[tl-i-1] << (DFRACT_BITS - SAMPLE_BITS - 1);
#endif
    }
    /* Left window slope */
    for (i=0; i<fl/2; i++)
    {
      FIXP_DBL tmp0;
      tmp0 = fMultDiv2((FIXP_PCM)timeData[i+nl], pLeftWindowPart[i].v.im);
      mdctData[(tl/2)+i+nl] = fMultSubDiv2(tmp0, (FIXP_PCM)timeData[tl-nl-i-1], pLeftWindowPart[i].v.re);
    }

/* Right window slope offset */
    for(i=0; i<nr; i++)
    {
#if SAMPLE_BITS == DFRACT_BITS    /* This should be SPC_BITS instead of DFRACT_BITS. */
      mdctData[(tl/2)-1-i] = - (FIXP_DBL) timeData[tl+i] >> (1);
#else
      mdctData[(tl/2)-1-i] = - (FIXP_DBL) timeData[tl+i] << (DFRACT_BITS - SAMPLE_BITS - 1);
#endif
    }
    /* Right window slope */
    for (i=0; i<fr/2; i++)
    {
      FIXP_DBL tmp1;
      tmp1 = fMultDiv2((FIXP_PCM)timeData[tl+nr+i], pRightWindowPart[i].v.re);
      mdctData[(tl/2)-nr-i-1] = -fMultAddDiv2(tmp1, (FIXP_PCM)timeData[(tl*2)-nr-i-1], pRightWindowPart[i].v.im);
    }
  }

if (filterType == FB_ELD)
  {
    const FIXP_WTB *pWindowELD=NULL;
    int i, N = frameLength, L = frameLength;

if (frameLength == 512) {
      pWindowELD = ELDAnalysis512;
    } else {
      pWindowELD = ELDAnalysis480;
    }

for(i=0;i<N/4;i++)
    {
      FIXP_DBL z0, outval;

z0 = (fMult((FIXP_PCM)timeData[L+N*3/4-1-i], pWindowELD[N/2-1-i])<< (WTS0-1)) + (fMult((FIXP_PCM)timeData[L+N*3/4+i], pWindowELD[N/2+i])<< (WTS0-1));

outval  = (fMultDiv2((FIXP_PCM)timeData[L+N*3/4-1-i], pWindowELD[N+N/2-1-i]) >> (-WTS1));
      outval += (fMultDiv2((FIXP_PCM)timeData[L+N*3/4+i], pWindowELD[N+N/2+i]) >> (-WTS1) );
      outval += (fMultDiv2(overlapAddBuffer[N/2+i], pWindowELD[2*N+i])>> (-WTS2-1));

overlapAddBuffer[N/2+i] = overlapAddBuffer[i];

overlapAddBuffer[i] = z0;
      mdctData[i] = overlapAddBuffer[N/2+i] + (fMultDiv2(overlapAddBuffer[N+N/2-1-i], pWindowELD[2*N+N/2+i]) >> (-WTS2-1));

mdctData[N-1-i] = outval;
      overlapAddBuffer[N+N/2-1-i] = outval;
    }

for(i=N/4;i<N/2;i++)
    {
      FIXP_DBL z0, outval;

z0 = fMult((FIXP_PCM)timeData[L+N*3/4-1-i], pWindowELD[N/2-1-i]) << (WTS0-1);

outval  = (fMultDiv2((FIXP_PCM)timeData[L+N*3/4-1-i], pWindowELD[N+N/2-1-i]) >> (-WTS1)) ;
      outval += (fMultDiv2(overlapAddBuffer[N/2+i], pWindowELD[2*N+i]) >> (-WTS2-1));

overlapAddBuffer[N/2+i] = overlapAddBuffer[i] + (fMult((FIXP_PCM)timeData[L-N/4+i], pWindowELD[N/2+i])<< (WTS0-1) );

overlapAddBuffer[i] = z0;
      mdctData[i] = overlapAddBuffer[N/2+i] + (fMultDiv2(overlapAddBuffer[N+N/2-1-i], pWindowELD[2*N+N/2+i]) >> (-WTS2-1));

mdctData[N-1-i] = outval;
      overlapAddBuffer[N+N/2-1-i] = outval;
    }
  }

dct_IV(mdctData, tl, mdctData_e);

*prevWindowShape = windowShape;

return 0;
}

C++程序 | 265行 | 10.08 KB

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