Include patched FDK-AAC in the repository

The initial idea was to get the DAB+ patch into upstream, but since
that follows the android source releases, there is no place for a custom
DAB+ patch there.

So instead of having to maintain a patched fdk-aac that has to have the
same .so version as the distribution package on which it is installed,
we prefer having a separate fdk-aac-dab library to avoid collision.

At that point, there's no reason to keep fdk-aac in a separate
repository, as odr-audioenc is the only tool that needs DAB+ encoding
support. Including it here simplifies installation, and makes it
consistent with toolame-dab, also shipped in this repository.

DAB+ decoding support (needed by ODR-SourceCompanion, dablin, etisnoop,
welle.io and others) can be done using upstream FDK-AAC.

1 files changed, 730 insertions, 0 deletions

diff --git a/fdk-aac/libFDK/src/mdct.cpp b/fdk-aac/libFDK/src/mdct.cpp
new file mode 100644
index 0000000..f5aa284
--- /dev/null
+++ b/fdk-aac/libFDK/src/mdct.cpp
@@ -0,0 +1,730 @@
+/* -----------------------------------------------------------------------------
+Software License for The Fraunhofer FDK AAC Codec Library for Android
+
+© Copyright  1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten
+Forschung e.V. 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 these patent claims through Via Licensing or
+directly from the patent owners, and therefore FDK AAC Codec 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 payment of copyright license fees provided that you
+satisfy the following conditions:
+
+You must retain the complete text of this software license in redistributions of
+the FDK AAC Codec or your modifications thereto in source code form.
+
+You must retain the complete text of this software license in the documentation
+and/or other materials provided with redistributions of the FDK AAC Codec or
+your modifications thereto in binary form. You must make available free of
+charge copies of the complete source code of the FDK AAC Codec and your
+modifications thereto to recipients of copies in binary form.
+
+The name of Fraunhofer may not be used to endorse or promote products derived
+from this library without prior written permission.
+
+You may not charge copyright license fees for anyone to use, copy or distribute
+the FDK AAC Codec software or your modifications thereto.
+
+Your modified versions of the FDK AAC Codec must carry prominent notices stating
+that you changed the software and the date of any change. For modified versions
+of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android"
+must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK
+AAC Codec Library for Android."
+
+3.    NO PATENT LICENSE
+
+NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without
+limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE.
+Fraunhofer provides no warranty of patent non-infringement with respect to this
+software.
+
+You may use this FDK AAC Codec software or modifications thereto only for
+purposes that are authorized by appropriate patent licenses.
+
+4.    DISCLAIMER
+
+This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright
+holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
+including but not limited to the implied warranties of merchantability and
+fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary,
+or consequential damages, including but not limited to procurement of substitute
+goods or services; loss of use, data, or profits, or business interruption,
+however caused and on any theory of liability, whether in contract, strict
+liability, or tort (including negligence), arising in any way out of the use of
+this software, even if advised of the possibility of such damage.
+
+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
+----------------------------------------------------------------------------- */
+
+/******************* Library for basic calculation routines ********************
+
+   Author(s):   Josef Hoepfl, Manuel Jander, Youliy Ninov, Daniel Hagel
+
+   Description: MDCT/MDST routines
+
+*******************************************************************************/
+
+#include "mdct.h"
+
+#include "FDK_tools_rom.h"
+#include "dct.h"
+#include "fixpoint_math.h"
+
+void mdct_init(H_MDCT hMdct, FIXP_DBL *overlap, INT overlapBufferSize) {
+  hMdct->overlap.freq = overlap;
+  // FDKmemclear(overlap, overlapBufferSize*sizeof(FIXP_DBL));
+  hMdct->prev_fr = 0;
+  hMdct->prev_nr = 0;
+  hMdct->prev_tl = 0;
+  hMdct->ov_size = overlapBufferSize;
+  hMdct->prevAliasSymmetry = 0;
+  hMdct->prevPrevAliasSymmetry = 0;
+  hMdct->pFacZir = NULL;
+  hMdct->pAsymOvlp = NULL;
+}
+
+/*
+This program implements the forward MDCT transform on an input block of data.
+The input block is in a form (A,B,C,D) where A,B,C and D are the respective
+1/4th segments of the block. The program takes the input block and folds it in
+the form:
+(-D-Cr,A-Br). This block is twice shorter and here the 'r' suffix denotes
+flipping of the sequence (reversing the order of the samples). While folding the
+input block in the above mentioned shorter block the program windows the data.
+Because the two operations (windowing and folding) are not implemented
+sequentially, but together the program's structure is not easy to understand.
+Once the output (already windowed) block (-D-Cr,A-Br) is ready it is passed to
+the DCT IV for processing.
+*/
+INT mdct_block(H_MDCT hMdct, const INT_PCM *RESTRICT timeData,
+               const INT noInSamples, FIXP_DBL *RESTRICT mdctData,
+               const INT nSpec, const INT tl, const FIXP_WTP *pRightWindowPart,
+               const INT fr, SHORT *pMdctData_e) {
+  int i, n;
+  /* 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 fl, nl, nr;
+  const FIXP_WTP *wls, *wrs;
+
+  wrs = pRightWindowPart;
+
+  /* Detect FRprevious / FL mismatches and override parameters accordingly */
+  if (hMdct->prev_fr ==
+      0) { /* At start just initialize and pass parameters as they are */
+    hMdct->prev_fr = fr;
+    hMdct->prev_wrs = wrs;
+    hMdct->prev_tl = tl;
+  }
+
+  /* Derive NR */
+  nr = (tl - fr) >> 1;
+
+  /* Skip input samples if tl is smaller than block size */
+  timeData += (noInSamples - tl) >> 1;
+
+  /* windowing */
+  for (n = 0; n < nSpec; n++) {
+    /*
+     * MDCT scale:
+     * + 1: fMultDiv2() in windowing.
+     * + 1: Because of factor 1/2 in Princen-Bradley compliant windowed TDAC.
+     */
+    INT mdctData_e = 1 + 1;
+
+    /* Derive left parameters */
+    wls = hMdct->prev_wrs;
+    fl = hMdct->prev_fr;
+    nl = (tl - fl) >> 1;
+
+    /* Here we implement a simplified version of what happens after the this
+    piece of code (see the comments below). We implement the folding of A and B
+    segments to (A-Br) but A is zero, because in this part of the MDCT sequence
+    the window coefficients with which A must be multiplied are zero.    */
+    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); /* 0(A)-Br */
+#endif
+    }
+
+    /* Implements the folding and windowing of the left part of the sequence,
+    that is segments A and B. The A segment is multiplied by the respective left
+    window coefficient and placed in a temporary variable.
+
+    tmp0 = fMultDiv2((FIXP_PCM)timeData[i+nl], pLeftWindowPart[i].v.im);
+
+    After this the B segment taken in reverse order is multiplied by the left
+    window and subtracted from the previously derived temporary variable, so
+    that finally we implement the A-Br operation. This output is written to the
+    right part of the MDCT output : (-D-Cr,A-Br).
+
+    mdctData[(tl/2)+i+nl] = fMultSubDiv2(tmp0, (FIXP_PCM)timeData[tl-nl-i-1],
+    pLeftWindowPart[i].v.re);//A*window-Br*window
+
+    The (A-Br) data is written to the output buffer (mdctData) without being
+    flipped.     */
+    for (i = 0; i < fl / 2; i++) {
+      FIXP_DBL tmp0;
+      tmp0 = fMultDiv2((FIXP_PCM)timeData[i + nl], wls[i].v.im); /* a*window */
+      mdctData[(tl / 2) + i + nl] =
+          fMultSubDiv2(tmp0, (FIXP_PCM)timeData[tl - nl - i - 1],
+                       wls[i].v.re); /* A*window-Br*window */
+    }
+
+    /* Right window slope offset */
+    /* Here we implement a simplified version of what happens after the this
+    piece of code (see the comments below). We implement the folding of C and D
+    segments to (-D-Cr) but D is zero, because in this part of the MDCT sequence
+    the window coefficients with which D must be multiplied are zero.    */
+    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); /* -C flipped at placing */
+#endif
+    }
+
+    /* Implements the folding and windowing of the right part of the sequence,
+    that is, segments C and D. The C segment is multiplied by the respective
+    right window coefficient and placed in a temporary variable.
+
+    tmp1 = fMultDiv2((FIXP_PCM)timeData[tl+nr+i], pRightWindowPart[i].v.re);
+
+    After this the D segment taken in reverse order is multiplied by the right
+    window and added from the previously derived temporary variable, so that we
+    get (C+Dr) operation. This output is negated to get (-C-Dr) and written to
+    the left part of the MDCT output while being reversed (flipped) at the same
+    time, so that from (-C-Dr) we get (-D-Cr)=> (-D-Cr,A-Br).
+
+    mdctData[(tl/2)-nr-i-1] = -fMultAddDiv2(tmp1,
+    (FIXP_PCM)timeData[(tl*2)-nr-i-1], pRightWindowPart[i].v.im);*/
+    for (i = 0; i < fr / 2; i++) {
+      FIXP_DBL tmp1;
+      tmp1 = fMultDiv2((FIXP_PCM)timeData[tl + nr + i],
+                       wrs[i].v.re); /* C*window */
+      mdctData[(tl / 2) - nr - i - 1] =
+          -fMultAddDiv2(tmp1, (FIXP_PCM)timeData[(tl * 2) - nr - i - 1],
+                        wrs[i].v.im); /* -(C*window+Dr*window) and flip before
+                                         placing -> -Cr - D */
+    }
+
+    /* We pass the shortened folded data (-D-Cr,A-Br) to the MDCT function */
+    dct_IV(mdctData, tl, &mdctData_e);
+
+    pMdctData_e[n] = (SHORT)mdctData_e;
+
+    timeData += tl;
+    mdctData += tl;
+
+    hMdct->prev_wrs = wrs;
+    hMdct->prev_fr = fr;
+    hMdct->prev_tl = tl;
+  }
+
+  return nSpec * tl;
+}
+
+void imdct_gain(FIXP_DBL *pGain_m, int *pGain_e, int tl) {
+  FIXP_DBL gain_m = *pGain_m;
+  int gain_e = *pGain_e;
+  int log2_tl;
+
+  gain_e += -MDCT_OUTPUT_GAIN - MDCT_OUT_HEADROOM + 1;
+  if (tl == 0) {
+    /* Dont regard the 2/N factor from the IDCT. It is compensated for somewhere
+     * else. */
+    *pGain_e = gain_e;
+    return;
+  }
+
+  log2_tl = DFRACT_BITS - 1 - fNormz((FIXP_DBL)tl);
+  gain_e += -log2_tl;
+
+  FDK_ASSERT(log2_tl - 2 >= 0);
+  FDK_ASSERT(log2_tl - 2 < 8*sizeof(int));
+
+  /* Detect non-radix 2 transform length and add amplitude compensation factor
+     which cannot be included into the exponent above */
+  switch ((tl) >> (log2_tl - 2)) {
+    case 0x7: /* 10 ms, 1/tl = 1.0/(FDKpow(2.0, -log2_tl) *
+                 0.53333333333333333333) */
+      if (gain_m == (FIXP_DBL)0) {
+        gain_m = FL2FXCONST_DBL(0.53333333333333333333f);
+      } else {
+        gain_m = fMult(gain_m, FL2FXCONST_DBL(0.53333333333333333333f));
+      }
+      break;
+    case 0x6: /* 3/4 of radix 2, 1/tl = 1.0/(FDKpow(2.0, -log2_tl) * 2.0/3.0) */
+      if (gain_m == (FIXP_DBL)0) {
+        gain_m = FL2FXCONST_DBL(2.0 / 3.0f);
+      } else {
+        gain_m = fMult(gain_m, FL2FXCONST_DBL(2.0 / 3.0f));
+      }
+      break;
+    case 0x5: /* 0.8 of radix 2 (e.g. tl 160), 1/tl = 1.0/(FDKpow(2.0, -log2_tl)
+               * 0.8/1.5) */
+      if (gain_m == (FIXP_DBL)0) {
+        gain_m = FL2FXCONST_DBL(0.53333333333333333333f);
+      } else {
+        gain_m = fMult(gain_m, FL2FXCONST_DBL(0.53333333333333333333f));
+      }
+      break;
+    case 0x4:
+      /* radix 2, nothing to do. */
+      break;
+    default:
+      /* unsupported */
+      FDK_ASSERT(0);
+      break;
+  }
+
+  *pGain_m = gain_m;
+  *pGain_e = gain_e;
+}
+
+INT imdct_drain(H_MDCT hMdct, FIXP_DBL *output, INT nrSamplesRoom) {
+  int buffered_samples = 0;
+
+  if (nrSamplesRoom > 0) {
+    buffered_samples = hMdct->ov_offset;
+
+    FDK_ASSERT(buffered_samples <= nrSamplesRoom);
+
+    if (buffered_samples > 0) {
+      FDKmemcpy(output, hMdct->overlap.time,
+                buffered_samples * sizeof(FIXP_DBL));
+      hMdct->ov_offset = 0;
+    }
+  }
+  return buffered_samples;
+}
+
+INT imdct_copy_ov_and_nr(H_MDCT hMdct, FIXP_DBL *pTimeData, INT nrSamples) {
+  FIXP_DBL *pOvl;
+  int nt, nf, i;
+
+  nt = fMin(hMdct->ov_offset, nrSamples);
+  nrSamples -= nt;
+  nf = fMin(hMdct->prev_nr, nrSamples);
+  FDKmemcpy(pTimeData, hMdct->overlap.time, nt * sizeof(FIXP_DBL));
+  pTimeData += nt;
+
+  pOvl = hMdct->overlap.freq + hMdct->ov_size - 1;
+  if (hMdct->prevPrevAliasSymmetry == 0) {
+    for (i = 0; i < nf; i++) {
+      FIXP_DBL x = -(*pOvl--);
+      *pTimeData = IMDCT_SCALE_DBL(x);
+      pTimeData++;
+    }
+  } else {
+    for (i = 0; i < nf; i++) {
+      FIXP_DBL x = (*pOvl--);
+      *pTimeData = IMDCT_SCALE_DBL(x);
+      pTimeData++;
+    }
+  }
+
+  return (nt + nf);
+}
+
+void imdct_adapt_parameters(H_MDCT hMdct, int *pfl, int *pnl, int tl,
+                            const FIXP_WTP *wls, int noOutSamples) {
+  int fl = *pfl, nl = *pnl;
+  int window_diff, use_current = 0, use_previous = 0;
+  if (hMdct->prev_tl == 0) {
+    hMdct->prev_wrs = wls;
+    hMdct->prev_fr = fl;
+    hMdct->prev_nr = (noOutSamples - fl) >> 1;
+    hMdct->prev_tl = noOutSamples;
+    hMdct->ov_offset = 0;
+    use_current = 1;
+  }
+
+  window_diff = (hMdct->prev_fr - fl) >> 1;
+
+  /* check if the previous window slope can be adjusted to match the current
+   * window slope */
+  if (hMdct->prev_nr + window_diff > 0) {
+    use_current = 1;
+  }
+  /* check if the current window slope can be adjusted to match the previous
+   * window slope */
+  if (nl - window_diff > 0) {
+    use_previous = 1;
+  }
+
+  /* if both is possible choose the larger of both window slope lengths */
+  if (use_current && use_previous) {
+    if (fl < hMdct->prev_fr) {
+      use_current = 0;
+    }
+  }
+  /*
+   * If the previous transform block is big enough, enlarge previous window
+   * overlap, if not, then shrink current window overlap.
+   */
+  if (use_current) {
+    hMdct->prev_nr += window_diff;
+    hMdct->prev_fr = fl;
+    hMdct->prev_wrs = wls;
+  } else {
+    nl -= window_diff;
+    fl = hMdct->prev_fr;
+  }
+
+  *pfl = fl;
+  *pnl = nl;
+}
+
+/*
+This program implements the inverse modulated lapped transform, a generalized
+version of the inverse MDCT transform. Setting none of the MLT_*_ALIAS_FLAG
+flags computes the IMDCT, setting all of them computes the IMDST. Other
+combinations of these flags compute type III transforms used by the RSVD60
+multichannel tool for transitions between MDCT/MDST. The following description
+relates to the IMDCT only.
+
+If we pass the data block (A,B,C,D,E,F) to the FORWARD MDCT it will produce two
+outputs. The first one will be over the (A,B,C,D) part =>(-D-Cr,A-Br) and the
+second one will be over the (C,D,E,F) part => (-F-Er,C-Dr), since there is a
+overlap between consequtive passes of the algorithm. This overlap is over the
+(C,D) segments. The two outputs will be given sequentially to the DCT IV
+algorithm. At the INVERSE MDCT side we get two consecutive outputs from the IDCT
+IV algorithm, namely the same blocks: (-D-Cr,A-Br) and (-F-Er,C-Dr). The first
+of them lands in the Overlap buffer and the second is in the working one, which,
+one algorithm pass later will substitute the one residing in the overlap
+register. The IMDCT algorithm has to produce the C and D segments from the two
+buffers. In order to do this we take the left part of the overlap
+buffer(-D-Cr,A-Br), namely (-D-Cr) and add it appropriately to the right part of
+the working buffer (-F-Er,C-Dr), namely (C-Dr), so that we get first the C
+segment and later the D segment. We do this in the following way: From the right
+part of the working buffer(C-Dr) we subtract the flipped left part of the
+overlap buffer(-D-Cr):
+
+Result = (C-Dr) - flipped(-D-Cr) = C -Dr + Dr + C = 2C
+We divide by two and get the C segment. What we did is adding the right part of
+the first frame to the left part of the second one.   While applying these
+operation we multiply the respective segments with the appropriate window
+functions.
+
+In order to get the D segment we do the following:
+From the negated second part of the working buffer(C-Dr) we subtract the flipped
+first part of the overlap buffer (-D-Cr):
+
+Result= - (C -Dr) - flipped(-D-Cr)= -C +Dr +Dr +C = 2Dr.
+After dividing by two and flipping we get the D segment.What we did is adding
+the right part of the first frame to the left part of the second one.   While
+applying these operation we multiply the respective segments with the
+appropriate window functions.
+
+Once we have obtained the C and D segments the overlap buffer is emptied and the
+current buffer is sent in it, so that the E and F segments are available for
+decoding in the next algorithm pass.*/
+INT imlt_block(H_MDCT hMdct, FIXP_DBL *output, FIXP_DBL *spectrum,
+               const SHORT scalefactor[], const INT nSpec,
+               const INT noOutSamples, const INT tl, const FIXP_WTP *wls,
+               INT fl, const FIXP_WTP *wrs, const INT fr, FIXP_DBL gain,
+               int flags) {
+  FIXP_DBL *pOvl;
+  FIXP_DBL *pOut0 = output, *pOut1;
+  INT nl, nr;
+  int w, i, nrSamples = 0, specShiftScale, transform_gain_e = 0;
+  int currAliasSymmetry = (flags & MLT_FLAG_CURR_ALIAS_SYMMETRY);
+
+  /* Derive NR and NL */
+  nr = (tl - fr) >> 1;
+  nl = (tl - fl) >> 1;
+
+  /* Include 2/N IMDCT gain into gain factor and exponent. */
+  imdct_gain(&gain, &transform_gain_e, tl);
+
+  /* Detect FRprevious / FL mismatches and override parameters accordingly */
+  if (hMdct->prev_fr != fl) {
+    imdct_adapt_parameters(hMdct, &fl, &nl, tl, wls, noOutSamples);
+  }
+
+  pOvl = hMdct->overlap.freq + hMdct->ov_size - 1;
+
+  if (noOutSamples > nrSamples) {
+    /* Purge buffered output. */
+    for (i = 0; i < hMdct->ov_offset; i++) {
+      *pOut0 = hMdct->overlap.time[i];
+      pOut0++;
+    }
+    nrSamples = hMdct->ov_offset;
+    hMdct->ov_offset = 0;
+  }
+
+  for (w = 0; w < nSpec; w++) {
+    FIXP_DBL *pSpec, *pCurr;
+    const FIXP_WTP *pWindow;
+
+    /* Detect FRprevious / FL mismatches and override parameters accordingly */
+    if (hMdct->prev_fr != fl) {
+      imdct_adapt_parameters(hMdct, &fl, &nl, tl, wls, noOutSamples);
+    }
+
+    specShiftScale = transform_gain_e;
+
+    /* Setup window pointers */
+    pWindow = hMdct->prev_wrs;
+
+    /* Current spectrum */
+    pSpec = spectrum + w * tl;
+
+    /* DCT IV of current spectrum. */
+    if (currAliasSymmetry == 0) {
+      if (hMdct->prevAliasSymmetry == 0) {
+        dct_IV(pSpec, tl, &specShiftScale);
+      } else {
+        FIXP_DBL _tmp[1024 + ALIGNMENT_DEFAULT / sizeof(FIXP_DBL)];
+        FIXP_DBL *tmp = (FIXP_DBL *)ALIGN_PTR(_tmp);
+        C_ALLOC_ALIGNED_REGISTER(tmp, sizeof(_tmp));
+        dct_III(pSpec, tmp, tl, &specShiftScale);
+        C_ALLOC_ALIGNED_UNREGISTER(tmp);
+      }
+    } else {
+      if (hMdct->prevAliasSymmetry == 0) {
+        FIXP_DBL _tmp[1024 + ALIGNMENT_DEFAULT / sizeof(FIXP_DBL)];
+        FIXP_DBL *tmp = (FIXP_DBL *)ALIGN_PTR(_tmp);
+        C_ALLOC_ALIGNED_REGISTER(tmp, sizeof(_tmp));
+        dst_III(pSpec, tmp, tl, &specShiftScale);
+        C_ALLOC_ALIGNED_UNREGISTER(tmp);
+      } else {
+        dst_IV(pSpec, tl, &specShiftScale);
+      }
+    }
+
+    /* Optional scaling of time domain - no yet windowed - of current spectrum
+     */
+    /* and de-scale current spectrum signal (time domain, no yet windowed) */
+    if (gain != (FIXP_DBL)0) {
+      for (i = 0; i < tl; i++) {
+        pSpec[i] = fMult(pSpec[i], gain);
+      }
+    }
+
+    {
+      int loc_scale =
+          fixmin_I(scalefactor[w] + specShiftScale, (INT)DFRACT_BITS - 1);
+      DWORD_ALIGNED(pSpec);
+      scaleValuesSaturate(pSpec, tl, loc_scale);
+    }
+
+    if (noOutSamples <= nrSamples) {
+      /* Divert output first half to overlap buffer if we already got enough
+       * output samples. */
+      pOut0 = hMdct->overlap.time + hMdct->ov_offset;
+      hMdct->ov_offset += hMdct->prev_nr + fl / 2;
+    } else {
+      /* Account output samples */
+      nrSamples += hMdct->prev_nr + fl / 2;
+    }
+
+    /* NR output samples 0 .. NR. -overlap[TL/2..TL/2-NR] */
+    if ((hMdct->pFacZir != 0) && (hMdct->prev_nr == fl / 2)) {
+      /* In the case of ACELP -> TCX20 -> FD short add FAC ZIR on nr signal part
+       */
+      for (i = 0; i < hMdct->prev_nr; i++) {
+        FIXP_DBL x = -(*pOvl--);
+        *pOut0 = IMDCT_SCALE_DBL(x + hMdct->pFacZir[i]);
+        pOut0++;
+      }
+      hMdct->pFacZir = NULL;
+    } else {
+      /* Here we implement a simplified version of what happens after the this
+      piece of code (see the comments below). We implement the folding of C and
+      D segments from (-D-Cr) but D is zero, because in this part of the MDCT
+      sequence the window coefficients with which D must be multiplied are zero.
+      "pOut0" writes sequentially the C block from left to right.   */
+      if (hMdct->prevPrevAliasSymmetry == 0) {
+        for (i = 0; i < hMdct->prev_nr; i++) {
+          FIXP_DBL x = -(*pOvl--);
+          *pOut0 = IMDCT_SCALE_DBL(x);
+          pOut0++;
+        }
+      } else {
+        for (i = 0; i < hMdct->prev_nr; i++) {
+          FIXP_DBL x = *pOvl--;
+          *pOut0 = IMDCT_SCALE_DBL(x);
+          pOut0++;
+        }
+      }
+    }
+
+    if (noOutSamples <= nrSamples) {
+      /* Divert output second half to overlap buffer if we already got enough
+       * output samples. */
+      pOut1 = hMdct->overlap.time + hMdct->ov_offset + fl / 2 - 1;
+      hMdct->ov_offset += fl / 2 + nl;
+    } else {
+      pOut1 = pOut0 + (fl - 1);
+      nrSamples += fl / 2 + nl;
+    }
+
+    /* output samples before window crossing point NR .. TL/2.
+     * -overlap[TL/2-NR..TL/2-NR-FL/2] + current[NR..TL/2] */
+    /* output samples after window crossing point TL/2 .. TL/2+FL/2.
+     * -overlap[0..FL/2] - current[TL/2..FL/2] */
+    pCurr = pSpec + tl - fl / 2;
+    DWORD_ALIGNED(pCurr);
+    C_ALLOC_ALIGNED_REGISTER(pWindow, fl);
+    DWORD_ALIGNED(pWindow);
+    C_ALLOC_ALIGNED_UNREGISTER(pWindow);
+
+    if (hMdct->prevPrevAliasSymmetry == 0) {
+      if (hMdct->prevAliasSymmetry == 0) {
+        if (!hMdct->pAsymOvlp) {
+          for (i = 0; i < fl / 2; i++) {
+            FIXP_DBL x0, x1;
+            cplxMultDiv2(&x1, &x0, *pCurr++, -*pOvl--, pWindow[i]);
+            *pOut0 = IMDCT_SCALE_DBL_LSH1(x0);
+            *pOut1 = IMDCT_SCALE_DBL_LSH1(-x1);
+            pOut0++;
+            pOut1--;
+          }
+        } else {
+          FIXP_DBL *pAsymOvl = hMdct->pAsymOvlp + fl / 2 - 1;
+          for (i = 0; i < fl / 2; i++) {
+            FIXP_DBL x0, x1;
+            x1 = -fMultDiv2(*pCurr, pWindow[i].v.re) +
+                 fMultDiv2(*pAsymOvl, pWindow[i].v.im);
+            x0 = fMultDiv2(*pCurr, pWindow[i].v.im) -
+                 fMultDiv2(*pOvl, pWindow[i].v.re);
+            pCurr++;
+            pOvl--;
+            pAsymOvl--;
+            *pOut0++ = IMDCT_SCALE_DBL_LSH1(x0);
+            *pOut1-- = IMDCT_SCALE_DBL_LSH1(x1);
+          }
+          hMdct->pAsymOvlp = NULL;
+        }
+      } else { /* prevAliasingSymmetry == 1 */
+        for (i = 0; i < fl / 2; i++) {
+          FIXP_DBL x0, x1;
+          cplxMultDiv2(&x1, &x0, *pCurr++, -*pOvl--, pWindow[i]);
+          *pOut0 = IMDCT_SCALE_DBL_LSH1(x0);
+          *pOut1 = IMDCT_SCALE_DBL_LSH1(x1);
+          pOut0++;
+          pOut1--;
+        }
+      }
+    } else { /* prevPrevAliasingSymmetry == 1 */
+      if (hMdct->prevAliasSymmetry == 0) {
+        for (i = 0; i < fl / 2; i++) {
+          FIXP_DBL x0, x1;
+          cplxMultDiv2(&x1, &x0, *pCurr++, *pOvl--, pWindow[i]);
+          *pOut0 = IMDCT_SCALE_DBL_LSH1(x0);
+          *pOut1 = IMDCT_SCALE_DBL_LSH1(-x1);
+          pOut0++;
+          pOut1--;
+        }
+      } else { /* prevAliasingSymmetry == 1 */
+        for (i = 0; i < fl / 2; i++) {
+          FIXP_DBL x0, x1;
+          cplxMultDiv2(&x1, &x0, *pCurr++, *pOvl--, pWindow[i]);
+          *pOut0 = IMDCT_SCALE_DBL_LSH1(x0);
+          *pOut1 = IMDCT_SCALE_DBL_LSH1(x1);
+          pOut0++;
+          pOut1--;
+        }
+      }
+    }
+
+    if (hMdct->pFacZir != 0) {
+      /* add FAC ZIR of previous ACELP -> mdct transition */
+      FIXP_DBL *pOut = pOut0 - fl / 2;
+      FDK_ASSERT(fl / 2 <= 128);
+      for (i = 0; i < fl / 2; i++) {
+        pOut[i] += IMDCT_SCALE_DBL(hMdct->pFacZir[i]);
+      }
+      hMdct->pFacZir = NULL;
+    }
+    pOut0 += (fl / 2) + nl;
+
+    /* NL output samples TL/2+FL/2..TL. - current[FL/2..0] */
+    pOut1 += (fl / 2) + 1;
+    pCurr = pSpec + tl - fl / 2 - 1;
+    /* Here we implement a simplified version of what happens above the this
+    piece of code (see the comments above). We implement the folding of C and D
+    segments from (C-Dr) but C is zero, because in this part of the MDCT
+    sequence the window coefficients with which C must be multiplied are zero.
+    "pOut1" writes sequentially the D block from left to right.   */
+    if (hMdct->prevAliasSymmetry == 0) {
+      for (i = 0; i < nl; i++) {
+        FIXP_DBL x = -(*pCurr--);
+        *pOut1++ = IMDCT_SCALE_DBL(x);
+      }
+    } else {
+      for (i = 0; i < nl; i++) {
+        FIXP_DBL x = *pCurr--;
+        *pOut1++ = IMDCT_SCALE_DBL(x);
+      }
+    }
+
+    /* Set overlap source pointer for next window pOvl = pSpec + tl/2 - 1; */
+    pOvl = pSpec + tl / 2 - 1;
+
+    /* Previous window values. */
+    hMdct->prev_nr = nr;
+    hMdct->prev_fr = fr;
+    hMdct->prev_tl = tl;
+    hMdct->prev_wrs = wrs;
+
+    /* Previous aliasing symmetry */
+    hMdct->prevPrevAliasSymmetry = hMdct->prevAliasSymmetry;
+    hMdct->prevAliasSymmetry = currAliasSymmetry;
+  }
+
+  /* Save overlap */
+
+  pOvl = hMdct->overlap.freq + hMdct->ov_size - tl / 2;
+  FDKmemcpy(pOvl, &spectrum[(nSpec - 1) * tl], (tl / 2) * sizeof(FIXP_DBL));
+
+  return nrSamples;
+}