Fraunhofer AAC codec.

License boilerplate update to follow.

Change-Id: I2810460c11a58b6d148d84673cc031f3685e79b5

1 files changed, 595 insertions, 0 deletions

diff --git a/libSBRdec/src/psdec_hybrid.cpp b/libSBRdec/src/psdec_hybrid.cpp
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+++ b/libSBRdec/src/psdec_hybrid.cpp
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+/****************************************************************************
+
+                     (C) Copyright Fraunhofer IIS (2005)
+                               All Rights Reserved
+
+    Please be advised that this software and/or program delivery is
+    Confidential Information of Fraunhofer and subject to and covered by the
+
+    Fraunhofer IIS Software Evaluation Agreement
+    between Google Inc. and  Fraunhofer
+    effective and in full force since March 1, 2012.
+
+    You may use this software and/or program only under the terms and
+    conditions described in the above mentioned Fraunhofer IIS Software
+    Evaluation Agreement. Any other and/or further use requires a separate agreement.
+
+
+   This software and/or program is protected by copyright law and international
+   treaties. Any reproduction or distribution of this software and/or program,
+   or any portion of it, may result in severe civil and criminal penalties, and
+   will be prosecuted to the maximum extent possible under law.
+
+  $Id$
+
+*******************************************************************************/
+
+#include "psdec_hybrid.h"
+
+
+#include "fft.h"
+#include "sbr_ram.h"
+
+#include "FDK_tools_rom.h"
+#include "sbr_rom.h"
+
+/*******************************************************************************
+ Functionname:  InitHybridFilterBank
+ *******************************************************************************
+
+ Description:   Init one instance of HANDLE_HYBRID stuct
+
+ Arguments:
+
+ Return:        none
+
+*******************************************************************************/
+
+
+SBR_ERROR
+InitHybridFilterBank ( HANDLE_HYBRID hs,          /*!< Handle to HYBRID struct. */
+                       SCHAR frameSize,           /*!< Framesize (in Qmf súbband samples). */
+                       SCHAR noBands,             /*!< Number of Qmf bands for hybrid filtering. */
+                       const UCHAR *pResolution ) /*!< Resolution in Qmf bands (length noBands). */
+{
+  SCHAR i;
+  UCHAR maxNoChannels = 0;
+
+  for (i = 0; i < noBands; i++) {
+    hs->pResolution[i] = pResolution[i];
+    if(pResolution[i] > maxNoChannels)
+      maxNoChannels = pResolution[i];
+  }
+
+  hs->nQmfBands     = noBands;
+  hs->frameSize     = frameSize;
+  hs->qmfBufferMove = HYBRID_FILTER_LENGTH - 1;
+
+  hs->sf_mQmfBuffer = 0;
+
+  return SBRDEC_OK;
+}
+
+/*******************************************************************************
+ Functionname:  dualChannelFiltering
+ *******************************************************************************
+
+ Description:   fast 2-channel real-valued filtering with 6-tap delay.
+
+ Arguments:
+
+ Return:        none
+
+*******************************************************************************/
+
+/*!
+2 channel filter
+<pre>
+   Filter Coefs:
+   0.0,
+   0.01899487526049,
+   0.0,
+   -0.07293139167538,
+   0.0,
+   0.30596630545168,
+   0.5,
+   0.30596630545168,
+   0.0,
+   -0.07293139167538,
+   0.0,
+   0.01899487526049,
+   0.0
+
+
+   Filter design:
+   h[q,n] = g[n] * cos(2pi/2 * q * (n-6) );  n = 0..12,  q = 0,1;
+
+   ->  h[0,n] = g[n] * 1;
+   ->  h[1,n] = g[n] * pow(-1,n);
+</pre>
+*/
+
+static void slotBasedDualChannelFiltering( const FIXP_DBL *pQmfReal,
+                                           const FIXP_DBL *pQmfImag,
+
+                                           FIXP_DBL       *mHybridReal,
+                                           FIXP_DBL       *mHybridImag)
+{
+
+  FIXP_DBL  t1, t3, t5, t6;
+
+  /* symmetric filter coefficients */
+
+  /*  you don't have to shift the result after fMult because of p2_13_20 <= 0.5 */
+  t1 = fMultDiv2(p2_13_20[1] , ( (pQmfReal[1] >> 1) + (pQmfReal[11] >> 1)));
+  t3 = fMultDiv2(p2_13_20[3] , ( (pQmfReal[3] >> 1) + (pQmfReal[ 9] >> 1)));
+  t5 = fMultDiv2(p2_13_20[5] , ( (pQmfReal[5] >> 1) + (pQmfReal[ 7] >> 1)));
+  t6 = fMultDiv2(p2_13_20[6] ,   (pQmfReal[6] >> 1) );
+
+  mHybridReal[0] = (t1 + t3 + t5 + t6) << 2;
+  mHybridReal[1] = (- t1 - t3 - t5 + t6) << 2;
+
+  t1 = fMultDiv2(p2_13_20[1] , ( (pQmfImag[1] >> 1) + (pQmfImag[11] >> 1)));
+  t3 = fMultDiv2(p2_13_20[3] , ( (pQmfImag[3] >> 1) + (pQmfImag[ 9] >> 1)));
+  t5 = fMultDiv2(p2_13_20[5] , ( (pQmfImag[5] >> 1) + (pQmfImag[ 7] >> 1)));
+  t6 = fMultDiv2(p2_13_20[6] ,    pQmfImag[6] >> 1 );
+
+  mHybridImag[0] = (t1 + t3 + t5 + t6) << 2;
+  mHybridImag[1] = (- t1 - t3 - t5 + t6) << 2;
+}
+
+
+/*******************************************************************************
+ Functionname:  eightChannelFiltering
+ *******************************************************************************
+
+ Description:   fast 8-channel complex-valued filtering with 6-tap delay.
+
+ Arguments:
+
+ Return:        none
+
+*******************************************************************************/
+/*!
+   8 channel filter
+
+   Implementation using a FFT of length 8
+<pre>
+   prototype filter coefficients:
+   0.00746082949812   0.02270420949825   0.04546865930473   0.07266113929591   0.09885108575264   0.11793710567217
+   0.125
+   0.11793710567217   0.09885108575264   0.07266113929591   0.04546865930473   0.02270420949825   0.00746082949812
+
+   Filter design:
+   N = 13; Q = 8;
+   h[q,n]       = g[n] * exp(j * 2 * pi / Q * (q + .5) * (n - 6));  n = 0..(N-1),  q = 0..(Q-1);
+
+   Time Signal:   x[t];
+   Filter Bank Output
+   y[q,t] = conv(x[t],h[q,t]) = conv(h[q,t],x[t]) = sum(x[k] * h[q, t - k] ) = sum(h[q, k] * x[t - k] ); k = 0..(N-1);
+
+   y[q,t] =   x[t - 12]*h[q, 12]  +  x[t - 11]*h[q, 11]  +  x[t - 10]*h[q, 10]  +  x[t -  9]*h[q,  9]
+           +  x[t -  8]*h[q,  8]  +  x[t -  7]*h[q,  7]
+           +  x[t -  6]*h[q,  6]
+           +  x[t -  5]*h[q,  5]  +  x[t -  4]*h[q,  4]
+           +  x[t -  3]*h[q,  3]  +  x[t -  2]*h[q,  2]  +  x[t -  1]*h[q,  1]  +  x[t -  0]*h[q,  0];
+
+   h'[q, n] = h[q,(N-1)-n] = g[n] * exp(j * 2 * pi / Q * (q + .5) * (6 - n));  n = 0..(N-1),  q = 0..(Q-1);
+
+   y[q,t] =   x[t - 12]*h'[q,  0]  +  x[t - 11]*h'[q,  1]  +  x[t - 10]*h'[q,  2]  +  x[t -  9]*h'[q,  3]
+           +  x[t -  8]*h'[q,  4]  +  x[t -  7]*h'[q,  5]
+           +  x[t -  6]*h'[q,  6]
+           +  x[t -  5]*h'[q,  7]  +  x[t -  4]*h'[q,  8]
+           +  x[t -  3]*h'[q,  9]  +  x[t -  2]*h'[q, 10]  +  x[t -  1]*h'[q, 11]  +  x[t -  0]*h'[q, 12];
+
+   Try to split off FFT Modulation Term:
+   FFT(x[t], q) = sum(x[t+k]*exp(-j*2*pi/N *q * k))
+                                           c                                           m
+   Step 1:  h'[q,n] = g[n] * ( exp(j * 2 * pi / 8 * .5 * (6 - n)) ) * ( exp (j * 2 * pi / 8 * q * (6 - n)) );
+
+    h'[q,n] = g[n] *c[n] * m[q,n]; (see above)
+    c[n]    = exp( j * 2 * pi / 8 * .5 * (6 - n) );
+    m[q,n]  = exp( j * 2 * pi / 8 *  q * (6 - n) );
+
+    y[q,t] = x[t -  0]*g[0]*c[0]*m[q,0]  +  x[t -  1]*g[1]*c[ 1]*m[q, 1]  + ...
+             ...                         +  x[t - 12]*g[2]*c[12]*m[q,12];
+
+                                                                              |
+    n                   m                            *exp(-j*2*pi)            |   n'                   fft
+-------------------------------------------------------------------------------------------------------------------------
+    0       exp( j * 2 * pi / 8 * q * 6) ->  exp(-j * 2 * pi / 8 * q * 2)     |   2         exp(-j * 2 * pi / 8 * q * 0)
+    1       exp( j * 2 * pi / 8 * q * 5) ->  exp(-j * 2 * pi / 8 * q * 3)     |   3         exp(-j * 2 * pi / 8 * q * 1)
+    2       exp( j * 2 * pi / 8 * q * 4) ->  exp(-j * 2 * pi / 8 * q * 4)     |   4         exp(-j * 2 * pi / 8 * q * 2)
+    3       exp( j * 2 * pi / 8 * q * 3) ->  exp(-j * 2 * pi / 8 * q * 5)     |   5         exp(-j * 2 * pi / 8 * q * 3)
+    4       exp( j * 2 * pi / 8 * q * 2) ->  exp(-j * 2 * pi / 8 * q * 6)     |   6         exp(-j * 2 * pi / 8 * q * 4)
+    5       exp( j * 2 * pi / 8 * q * 1) ->  exp(-j * 2 * pi / 8 * q * 7)     |   7         exp(-j * 2 * pi / 8 * q * 5)
+    6       exp( j * 2 * pi / 8 * q * 0)                                      |   0         exp(-j * 2 * pi / 8 * q * 6)
+    7       exp(-j * 2 * pi / 8 * q * 1)                                      |   1         exp(-j * 2 * pi / 8 * q * 7)
+    8       exp(-j * 2 * pi / 8 * q * 2)                                      |   2
+    9       exp(-j * 2 * pi / 8 * q * 3)                                      |   3
+    10      exp(-j * 2 * pi / 8 * q * 4)                                      |   4
+    11      exp(-j * 2 * pi / 8 * q * 5)                                      |   5
+    12      exp(-j * 2 * pi / 8 * q * 6)                                      |   6
+
+
+    now use fft modulation coefficients
+    m[6]  =       = fft[0]
+    m[7]  =       = fft[1]
+    m[8]  = m[ 0] = fft[2]
+    m[9]  = m[ 1] = fft[3]
+    m[10] = m[ 2] = fft[4]
+    m[11] = m[ 3] = fft[5]
+    m[12] = m[ 4] = fft[6]
+            m[ 5] = fft[7]
+
+    y[q,t] = (                       x[t- 6]*g[ 6]*c[ 6] ) * fft[q,0]  +
+             (                       x[t- 7]*g[ 7]*c[ 7] ) * fft[q,1]  +
+             ( x[t- 0]*g[ 0]*c[ 0] + x[t- 8]*g[ 8]*c[ 8] ) * fft[q,2]  +
+             ( x[t- 1]*g[ 1]*c[ 1] + x[t- 9]*g[ 9]*c[ 9] ) * fft[q,3]  +
+             ( x[t- 2]*g[ 2]*c[ 2] + x[t-10]*g[10]*c[10] ) * fft[q,4]  +
+             ( x[t- 3]*g[ 3]*c[ 3] + x[t-11]*g[11]*c[11] ) * fft[q,5]  +
+             ( x[t- 4]*g[ 4]*c[ 4] + x[t-12]*g[12]*c[12] ) * fft[q,6]  +
+             ( x[t- 5]*g[ 5]*c[ 5]                       ) * fft[q,7];
+
+    pre twiddle factors c[n] = exp(j * 2 * pi / 8 * .5 * (6 - n));
+    n                c]           |  n                c[n]         |  n                c[n]
+---------------------------------------------------------------------------------------------------
+    0       exp( j * 6 * pi / 8)  |  1       exp( j * 5 * pi / 8)  |  2       exp( j * 4 * pi / 8)
+    3       exp( j * 3 * pi / 8)  |  4       exp( j * 2 * pi / 8)  |  5       exp( j * 1 * pi / 8)
+    6       exp( j * 0 * pi / 8)  |  7       exp(-j * 1 * pi / 8)  |  8       exp(-j * 2 * pi / 8)
+    9       exp(-j * 3 * pi / 8)  | 10       exp(-j * 4 * pi / 8)  | 11       exp(-j * 5 * pi / 8)
+   12       exp(-j * 6 * pi / 8)  |                                |
+</pre>
+*/
+
+/* defining rotation factors for *ChannelFiltering */
+
+#define cos0Pi    FL2FXCONST_DBL( 1.f)
+#define sin0Pi    FL2FXCONST_DBL( 0.f)
+
+#define cos1Pi    FL2FXCONST_DBL(-1.f)
+#define sin1Pi    FL2FXCONST_DBL( 0.f)
+
+#define cos1Pi_2  FL2FXCONST_DBL( 0.f)
+#define sin1Pi_2  FL2FXCONST_DBL( 1.f)
+
+#define cos1Pi_3  FL2FXCONST_DBL( 0.5f)
+#define sin1Pi_3  FL2FXCONST_DBL( 0.86602540378444f)
+
+#define cos0Pi_4  cos0Pi
+#define cos1Pi_4  FL2FXCONST_DBL(0.70710678118655f)
+#define cos2Pi_4  cos1Pi_2
+#define cos3Pi_4  (-cos1Pi_4)
+#define cos4Pi_4  (-cos0Pi_4)
+#define cos5Pi_4  cos3Pi_4
+#define cos6Pi_4  cos2Pi_4
+
+#define sin0Pi_4  sin0Pi
+#define sin1Pi_4  FL2FXCONST_DBL(0.70710678118655f)
+#define sin2Pi_4  sin1Pi_2
+#define sin3Pi_4  sin1Pi_4
+#define sin4Pi_4  sin0Pi_4
+#define sin5Pi_4  (-sin3Pi_4)
+#define sin6Pi_4  (-sin2Pi_4)
+
+#define cos0Pi_8  cos0Pi
+#define cos1Pi_8  FL2FXCONST_DBL(0.92387953251129f)
+#define cos2Pi_8  cos1Pi_4
+#define cos3Pi_8  FL2FXCONST_DBL(0.38268343236509f)
+#define cos4Pi_8  cos2Pi_4
+#define cos5Pi_8  (-cos3Pi_8)
+#define cos6Pi_8  (-cos2Pi_8)
+
+#define sin0Pi_8  sin0Pi
+#define sin1Pi_8  cos3Pi_8
+#define sin2Pi_8  sin1Pi_4
+#define sin3Pi_8  cos1Pi_8
+#define sin4Pi_8  sin2Pi_4
+#define sin5Pi_8  sin3Pi_8
+#define sin6Pi_8  sin1Pi_4
+
+#if defined(ARCH_PREFER_MULT_32x16)
+  #define FIXP_HYB FIXP_SGL
+  #define FIXP_CAST FX_DBL2FX_SGL
+#else
+  #define FIXP_HYB FIXP_DBL
+  #define FIXP_CAST
+#endif
+
+static const FIXP_HYB  cr[13] =
+{
+   FIXP_CAST(cos6Pi_8), FIXP_CAST(cos5Pi_8), FIXP_CAST(cos4Pi_8),
+   FIXP_CAST(cos3Pi_8), FIXP_CAST(cos2Pi_8), FIXP_CAST(cos1Pi_8),
+   FIXP_CAST(cos0Pi_8),
+   FIXP_CAST(cos1Pi_8), FIXP_CAST(cos2Pi_8), FIXP_CAST(cos3Pi_8),
+   FIXP_CAST(cos4Pi_8), FIXP_CAST(cos5Pi_8), FIXP_CAST(cos6Pi_8)
+};
+
+static const FIXP_HYB  ci[13] =
+{
+   FIXP_CAST( sin6Pi_8), FIXP_CAST( sin5Pi_8), FIXP_CAST( sin4Pi_8),
+   FIXP_CAST( sin3Pi_8), FIXP_CAST( sin2Pi_8), FIXP_CAST( sin1Pi_8),
+   FIXP_CAST( sin0Pi_8) ,
+   FIXP_CAST(-sin1Pi_8), FIXP_CAST(-sin2Pi_8), FIXP_CAST(-sin3Pi_8),
+   FIXP_CAST(-sin4Pi_8), FIXP_CAST(-sin5Pi_8), FIXP_CAST(-sin6Pi_8)
+};
+
+static void slotBasedEightChannelFiltering( const FIXP_DBL *pQmfReal,
+                                            const FIXP_DBL *pQmfImag,
+
+                                            FIXP_DBL  *mHybridReal,
+                                            FIXP_DBL  *mHybridImag)
+{
+
+  int bin;
+  FIXP_DBL _fft[128 + ALIGNMENT_DEFAULT - 1];
+  FIXP_DBL *fft = (FIXP_DBL *)ALIGN_PTR(_fft);
+
+#if defined(ARCH_PREFER_MULT_32x16)
+  const FIXP_SGL *p = p8_13_20; /* BASELINE_PS */
+#else
+  const FIXP_DBL *p = p8_13_20; /* BASELINE_PS */
+#endif
+
+  /* pre twiddeling */
+
+  /*   x*(a*b + c*d) = fMultDiv2(x, fMultAddDiv2(fMultDiv2(a, b), c, d)) */
+  /*   x*(a*b - c*d) = fMultDiv2(x, fMultSubDiv2(fMultDiv2(a, b), c, d)) */
+  FIXP_DBL accu1, accu2, accu3, accu4;
+
+  #define TWIDDLE_1(n_0,n_1,n_2)                                                        \
+         cplxMultDiv2(&accu1, &accu2, pQmfReal[n_0], pQmfImag[n_0], cr[n_0], ci[n_0]);  \
+         accu1 = fMultDiv2(p[n_0], accu1);                                              \
+         accu2 = fMultDiv2(p[n_0], accu2);                                              \
+         cplxMultDiv2(&accu3, &accu4, pQmfReal[n_1], pQmfImag[n_1], cr[n_1], ci[n_1]);  \
+         accu3 = fMultDiv2(p[n_1], accu3);                                              \
+         accu4 = fMultDiv2(p[n_1], accu4);                                              \
+         fft[FIXP_FFT_IDX_R(n_2)] = accu1 + accu3;                                      \
+         fft[FIXP_FFT_IDX_I(n_2)] = accu2 + accu4;
+
+  #define TWIDDLE_0(n_0,n_1)                                                            \
+         cplxMultDiv2(&accu1, &accu2, pQmfReal[n_0], pQmfImag[n_0], cr[n_0], ci[n_0]);  \
+         fft[FIXP_FFT_IDX_R(n_1)] = fMultDiv2(p[n_0], accu1);                           \
+         fft[FIXP_FFT_IDX_I(n_1)] = fMultDiv2(p[n_0], accu2);
+
+  TWIDDLE_0( 6, 0)
+  TWIDDLE_0( 7, 1)
+
+  TWIDDLE_1( 0, 8, 2)
+  TWIDDLE_1( 1, 9, 3)
+  TWIDDLE_1( 2,10, 4)
+  TWIDDLE_1( 3,11, 5)
+  TWIDDLE_1( 4,12, 6)
+
+  TWIDDLE_0( 5, 7)
+
+  fft_8 (fft);
+
+  /* resort fft data into output array*/
+  for(bin=0; bin<8;bin++ ) {
+    mHybridReal[bin] = fft[FIXP_FFT_IDX_R(bin)] << 4;
+    mHybridImag[bin] = fft[FIXP_FFT_IDX_I(bin)] << 4;
+  }
+}
+
+
+/*******************************************************************************
+ Functionname:  fillHybridDelayLine
+ *******************************************************************************
+
+ Description:   The delay line of the hybrid filter is filled and copied from
+                left to right.
+
+ Return:        none
+
+*******************************************************************************/
+
+void
+fillHybridDelayLine( FIXP_DBL **fixpQmfReal,          /*!< Qmf real Values    */
+                     FIXP_DBL **fixpQmfImag,          /*!< Qmf imag Values    */
+                     FIXP_DBL   fixpHybridLeftR[12],  /*!< Hybrid real Values left channel  */
+                     FIXP_DBL   fixpHybridLeftI[12],  /*!< Hybrid imag Values left channel  */
+                     FIXP_DBL   fixpHybridRightR[12], /*!< Hybrid real Values right channel */
+                     FIXP_DBL   fixpHybridRightI[12], /*!< Hybrid imag Values right channel */
+                     HANDLE_HYBRID hHybrid )
+{
+  int i;
+
+  for (i = 0; i < HYBRID_FILTER_DELAY; i++) {
+    slotBasedHybridAnalysis ( fixpQmfReal[i],
+                              fixpQmfReal[i],
+                              fixpHybridLeftR,
+                              fixpHybridLeftI,
+                              hHybrid );
+  }
+
+  FDKmemcpy(fixpHybridRightR, fixpHybridLeftR, sizeof(FIXP_DBL)*NO_SUB_QMF_CHANNELS);
+  FDKmemcpy(fixpHybridRightI, fixpHybridLeftI, sizeof(FIXP_DBL)*NO_SUB_QMF_CHANNELS);
+}
+
+
+/*******************************************************************************
+ Functionname:  slotBasedHybridAnalysis
+ *******************************************************************************
+
+ Description:   The lower QMF subbands are further split to provide better
+                frequency resolution for PS processing.
+
+  Return:        none
+
+*******************************************************************************/
+
+
+void
+slotBasedHybridAnalysis ( FIXP_DBL *fixpQmfReal,      /*!< Qmf real Values */
+                          FIXP_DBL *fixpQmfImag,      /*!< Qmf imag Values */
+
+                          FIXP_DBL  fixpHybridReal[12],   /*!< Hybrid real Values */
+                          FIXP_DBL  fixpHybridImag[12],   /*!< Hybrid imag Values */
+
+                          HANDLE_HYBRID hHybrid)
+{
+  int  k, band;
+  HYBRID_RES hybridRes;
+  int  chOffset = 0;
+
+  C_ALLOC_SCRATCH_START(pTempRealSlot, FIXP_DBL, 4*HYBRID_FILTER_LENGTH);
+
+  FIXP_DBL *pTempImagSlot = pTempRealSlot + HYBRID_FILTER_LENGTH;
+  FIXP_DBL *pWorkRealSlot = pTempImagSlot + HYBRID_FILTER_LENGTH;
+  FIXP_DBL *pWorkImagSlot = pWorkRealSlot + HYBRID_FILTER_LENGTH;
+
+  /*!
+  Hybrid filtering is applied to the first hHybrid->nQmfBands QMF bands (3 when 10 or 20 stereo bands
+  are used, 5 when 34 stereo bands are used). For the remaining QMF bands a delay would be necessary.
+  But there is no need to implement a delay because there is a look-ahead of HYBRID_FILTER_DELAY = 6
+  QMF samples in the low-band buffer.
+  */
+
+  for(band = 0; band < hHybrid->nQmfBands; band++) {
+
+    /*  get hybrid resolution per qmf band                */
+    /*  in case of baseline ps 10/20 band stereo mode :   */
+    /*                                                    */
+    /*             qmfBand[0] : 8 ( HYBRID_8_CPLX )       */
+    /*             qmfBand[1] : 2 ( HYBRID_2_REAL )       */
+    /*             qmfBand[2] : 2 ( HYBRID_2_REAL )       */
+    /*                                                    */
+    /*  (split the 3 lower qmf band to 12 hybrid bands)   */
+
+    hybridRes = (HYBRID_RES)hHybrid->pResolution[band];
+
+    FDKmemcpy(pWorkRealSlot, hHybrid->mQmfBufferRealSlot[band], hHybrid->qmfBufferMove * sizeof(FIXP_DBL));
+    FDKmemcpy(pWorkImagSlot, hHybrid->mQmfBufferImagSlot[band], hHybrid->qmfBufferMove * sizeof(FIXP_DBL));
+
+    pWorkRealSlot[hHybrid->qmfBufferMove] = fixpQmfReal[band];
+    pWorkImagSlot[hHybrid->qmfBufferMove] = fixpQmfImag[band];
+
+    FDKmemcpy(hHybrid->mQmfBufferRealSlot[band], pWorkRealSlot + 1, hHybrid->qmfBufferMove * sizeof(FIXP_DBL));
+    FDKmemcpy(hHybrid->mQmfBufferImagSlot[band], pWorkImagSlot + 1, hHybrid->qmfBufferMove * sizeof(FIXP_DBL));
+
+    if (fixpQmfReal) {
+
+      /* actual filtering only if output signal requested */
+      switch( hybridRes ) {
+
+      /* HYBRID_2_REAL & HYBRID_8_CPLX are only needful for baseline ps */
+      case HYBRID_2_REAL:
+
+        slotBasedDualChannelFiltering( pWorkRealSlot,
+                                       pWorkImagSlot,
+                                       pTempRealSlot,
+                                       pTempImagSlot);
+        break;
+
+      case HYBRID_8_CPLX:
+
+        slotBasedEightChannelFiltering( pWorkRealSlot,
+                                        pWorkImagSlot,
+                                        pTempRealSlot,
+                                        pTempImagSlot);
+        break;
+
+      default:
+        FDK_ASSERT(0);
+      }
+
+      for(k = 0; k < (SCHAR)hybridRes; k++) {
+        fixpHybridReal [chOffset + k] = pTempRealSlot[k];
+        fixpHybridImag [chOffset + k] = pTempImagSlot[k];
+      }
+      chOffset += hybridRes;
+    } /* if (mHybridReal) */
+  }
+
+  /* group hybrid channels 3+4 -> 3 and 2+5 -> 2 */
+  fixpHybridReal[3] += fixpHybridReal[4];
+  fixpHybridImag[3] += fixpHybridImag[4];
+  fixpHybridReal[4] = (FIXP_DBL)0;
+  fixpHybridImag[4] = (FIXP_DBL)0;
+
+  fixpHybridReal[2] += fixpHybridReal[5];
+  fixpHybridImag[2] += fixpHybridImag[5];
+  fixpHybridReal[5] = (FIXP_DBL)0;
+  fixpHybridImag[5] = (FIXP_DBL)0;
+
+  /* free memory on scratch */
+  C_ALLOC_SCRATCH_END(pTempRealSlot, FIXP_DBL, 4*HYBRID_FILTER_LENGTH);
+
+}
+
+
+/*******************************************************************************
+ Functionname:  slotBasedHybridSynthesis
+ *******************************************************************************
+
+ Description:  The coefficients offering higher resolution for the lower QMF
+               channel are simply added prior to the synthesis with the 54
+               subbands QMF.
+
+ Arguments:
+
+ Return:        none
+
+*******************************************************************************/
+
+/*! <pre>
+      l,r0(n) ---\
+      l,r1(n) ---- + --\
+      l,r2(n) ---/      \
+                         + --> F0(w)
+      l,r3(n) ---\      /
+      l,r4(n) ---- + --/
+      l,r5(n) ---/
+
+
+      l,r6(n) ---\
+                  + ---------> F1(w)
+      l,r7(n) ---/
+
+
+      l,r8(n) ---\
+                  + ---------> F2(w)
+      l,r9(n) ---/
+
+    </pre>
+      Hybrid QMF synthesis filterbank for the 10 and 20 stereo-bands configurations. The
+      coefficients offering higher resolution for the lower QMF channel are simply added
+      prior to the synthesis with the 54 subbands QMF.
+
+      [see ISO/IEC 14496-3:2001/FDAM 2:2004(E) - Page 52]
+*/
+
+
+void
+slotBasedHybridSynthesis ( FIXP_DBL  *fixpHybridReal,  /*!< Hybrid real Values */
+                           FIXP_DBL  *fixpHybridImag,  /*!< Hybrid imag Values */
+                           FIXP_DBL  *fixpQmfReal,     /*!< Qmf real Values */
+                           FIXP_DBL  *fixpQmfImag,     /*!< Qmf imag Values */
+                           HANDLE_HYBRID hHybrid )     /*!< Handle to HYBRID struct. */
+{
+  int  k, band;
+
+  HYBRID_RES hybridRes;
+  int  chOffset = 0;
+
+  for(band = 0; band < hHybrid->nQmfBands; band++) {
+
+    FIXP_DBL qmfReal = FL2FXCONST_DBL(0.f);
+    FIXP_DBL qmfImag = FL2FXCONST_DBL(0.f);
+    hybridRes = (HYBRID_RES)hHybrid->pResolution[band];
+
+    for(k = 0; k < (SCHAR)hybridRes; k++) {
+      qmfReal += fixpHybridReal[chOffset + k];
+      qmfImag += fixpHybridImag[chOffset + k];
+    }
+
+    fixpQmfReal[band] = qmfReal;
+    fixpQmfImag[band] = qmfImag;
+
+    chOffset += hybridRes;
+  }
+}
+
+
+