Fraunhofer AAC codec.

License boilerplate update to follow.

Change-Id: I2810460c11a58b6d148d84673cc031f3685e79b5

1 files changed, 339 insertions, 0 deletions

diff --git a/libFDK/src/mdct.cpp b/libFDK/src/mdct.cpp
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+/***************************  Fraunhofer IIS FDK Tools  **********************
+
+                        (C) Copyright Fraunhofer IIS (2011)
+                               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.
+
+
+   $Id$
+   Author(s):   Josef Hoepfl, Manuel Jander
+   Description: MDCT routines
+
+   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.
+
+******************************************************************************/
+
+#include "mdct.h"
+
+
+#include "FDK_tools_rom.h"
+#include "dct.h"
+#include "fixpoint_math.h"
+
+#define OPT_OVERLAP_ADD
+
+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;
+}
+
+INT  mdct( H_MDCT hMdct,
+           FIXP_DBL *spectrum,
+           INT *scalefactor,
+           INT_PCM *input,
+           INT tl,
+           INT nr,
+           INT fr,
+           const FIXP_WTP *wrs )
+{
+  /* Fold and windowing */
+
+  /* DCT IV */
+  // dct_IV();
+  return 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;
+
+  log2_tl = DFRACT_BITS-1-fNormz((FIXP_DBL)tl);
+
+  gain_e += -MDCT_OUTPUT_GAIN - log2_tl - MDCT_OUT_HEADROOM + 1;
+
+  /* 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 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);
+  nrSamples -= nf;
+  FDKmemcpy(pTimeData, hMdct->overlap.time, nt*sizeof(FIXP_DBL));
+  pTimeData += nt;
+
+  pOvl = hMdct->overlap.freq + hMdct->ov_size - 1;
+  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;
+    } else {
+      use_previous = 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;
+}
+
+INT  imdct_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
+        )
+{
+  FIXP_DBL *pOvl;
+  FIXP_DBL *pOut0 = output, *pOut1;
+  INT nl, nr;
+  int w, i, nrSamples = 0, specShiftScale, transform_gain_e = 0;
+
+  /* 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;
+
+    specShiftScale = transform_gain_e;
+
+    /* Setup window pointers */
+    pWindow = hMdct->prev_wrs;
+
+    /* Current spectrum */
+    pSpec = spectrum+w*tl;
+
+    /* DCT IV of current spectrum. */
+    dct_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) {
+      scaleValuesWithFactor(pSpec, gain, tl, scalefactor[w] + specShiftScale);
+    } else {
+      scaleValues(pSpec, tl, scalefactor[w] + specShiftScale);
+    }
+
+    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] */
+    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;
+    for (i=0; i<fl/2; i++) {
+      FIXP_DBL x0, x1;
+
+      cplxMult(&x1, &x0, *pCurr++, - *pOvl--, pWindow[i]);
+      *pOut0 = IMDCT_SCALE_DBL(x0);
+      *pOut1 = IMDCT_SCALE_DBL(-x1);
+      pOut0 ++;
+      pOut1 --;
+    }
+    pOut0 += (fl/2);
+
+    /* NL output samples TL/2+FL/2..TL. - current[FL/2..0] */
+    pOut1 += (fl/2) + 1;
+    pCurr = pSpec + tl - fl/2 - 1;
+    for (i=0; i<nl; i++) {
+      FIXP_DBL x = - (*pCurr--);
+      *pOut1 = IMDCT_SCALE_DBL(x);
+      pOut1 ++;
+    }
+
+    /* 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;
+  }
+
+  /* Save overlap */
+  
+  pOvl = hMdct->overlap.freq + hMdct->ov_size - tl/2;
+  FDK_ASSERT(pOvl >= hMdct->overlap.time + hMdct->ov_offset);
+  FDK_ASSERT(tl/2 <= hMdct->ov_size);
+  for (i=0; i<tl/2; i++) {
+    pOvl[i] = spectrum[i+(nSpec-1)*tl];
+  }
+
+  return nrSamples;
+}
+