Fraunhofer AAC codec.

License boilerplate update to follow.

Change-Id: I2810460c11a58b6d148d84673cc031f3685e79b5

1 files changed, 235 insertions, 0 deletions

diff --git a/libAACdec/src/stereo.cpp b/libAACdec/src/stereo.cpp
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+/*****************************  MPEG-4 AAC Decoder  **************************
+
+                        (C) Copyright Fraunhofer IIS (2004)
+                               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
+   Description: joint stereo processing
+
+   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 "stereo.h"
+
+
+#include "aac_rom.h"
+#include "FDK_bitstream.h"
+#include "channelinfo.h"
+
+enum
+{
+  L = 0,
+  R = 1
+};
+
+
+int CJointStereo_Read(
+        HANDLE_FDK_BITSTREAM bs,
+        CJointStereoData *pJointStereoData,
+        const int windowGroups,
+        const int scaleFactorBandsTransmitted,
+        const UINT flags
+        )
+{
+  int group,band;
+
+  pJointStereoData->MsMaskPresent = (UCHAR) FDKreadBits(bs,2);
+
+  FDKmemclear(pJointStereoData->MsUsed, scaleFactorBandsTransmitted*sizeof(UCHAR));
+
+  switch (pJointStereoData->MsMaskPresent)
+  {
+    case 0 : /* no M/S */
+      /* all flags are already cleared */
+      break ;
+
+    case 1 : /* read ms_used */
+
+      for (group=0; group<windowGroups; group++)
+      {
+        for (band=0; band<scaleFactorBandsTransmitted; band++)
+        {
+          pJointStereoData->MsUsed[band] |= (FDKreadBits(bs,1) << group);
+        }
+      }
+      break ;
+
+    case 2 : /* full spectrum M/S */
+
+      for (band=0; band<scaleFactorBandsTransmitted; band++)
+      {
+        pJointStereoData->MsUsed[band] = 255 ;  /* set all flags to 1 */
+      }
+      break ;
+  }
+
+  return 0;
+}
+
+void CJointStereo_ApplyMS(
+        CAacDecoderChannelInfo *pAacDecoderChannelInfo[2],
+        const SHORT *pScaleFactorBandOffsets,
+        const UCHAR *pWindowGroupLength,
+        const int windowGroups,
+        const int scaleFactorBandsTransmittedL,
+        const int scaleFactorBandsTransmittedR
+        )
+{
+  CJointStereoData *pJointStereoData = &pAacDecoderChannelInfo[L]->pComData->jointStereoData;
+  int window, group, scaleFactorBandsTransmitted;
+
+  FDK_ASSERT(scaleFactorBandsTransmittedL == scaleFactorBandsTransmittedR);
+  scaleFactorBandsTransmitted = scaleFactorBandsTransmittedL;
+  for (window = 0, group = 0; group < windowGroups; group++)
+  {
+    UCHAR groupMask = 1 << group;
+
+    for (int groupwin=0; groupwin<pWindowGroupLength[group]; groupwin++, window++)
+    {
+      int band;
+      FIXP_DBL *leftSpectrum, *rightSpectrum;
+      SHORT *leftScale = &pAacDecoderChannelInfo[L]->pDynData->aSfbScale[window*16];
+      SHORT *rightScale = &pAacDecoderChannelInfo[R]->pDynData->aSfbScale[window*16];
+
+      leftSpectrum = SPEC(pAacDecoderChannelInfo[L]->pSpectralCoefficient, window, pAacDecoderChannelInfo[L]->granuleLength);
+      rightSpectrum = SPEC(pAacDecoderChannelInfo[R]->pSpectralCoefficient, window, pAacDecoderChannelInfo[R]->granuleLength);
+
+      for (band=0; band<scaleFactorBandsTransmitted; band++)
+      {
+        if (pJointStereoData->MsUsed[band] & groupMask)
+        {
+          int lScale=leftScale[band];
+          int rScale=rightScale[band];
+          int commonScale=lScale > rScale ? lScale:rScale;
+
+          /* ISO/IEC 14496-3 Chapter 4.6.8.1.1 :
+             M/S joint channel coding can only be used if common_window is ‘1’. */
+          FDK_ASSERT(GetWindowSequence(&pAacDecoderChannelInfo[L]->icsInfo) == GetWindowSequence(&pAacDecoderChannelInfo[R]->icsInfo));
+          FDK_ASSERT(GetWindowShape(&pAacDecoderChannelInfo[L]->icsInfo) == GetWindowShape(&pAacDecoderChannelInfo[R]->icsInfo));
+
+          commonScale++;
+          leftScale[band]=commonScale;
+          rightScale[band]=commonScale;
+
+          lScale = fMin(DFRACT_BITS-1, commonScale - lScale);
+          rScale = fMin(DFRACT_BITS-1, commonScale - rScale);
+
+          FDK_ASSERT(lScale >= 0 && rScale >= 0);
+
+          for (int index=pScaleFactorBandOffsets[band]; index<pScaleFactorBandOffsets[band+1]; index++)
+          {
+            FIXP_DBL leftCoefficient  = leftSpectrum [index] ;
+            FIXP_DBL rightCoefficient = rightSpectrum [index] ;
+
+            leftCoefficient >>= lScale ;
+            rightCoefficient >>= rScale ;
+
+            leftSpectrum [index] = leftCoefficient + rightCoefficient ;
+            rightSpectrum [index] = leftCoefficient - rightCoefficient ;
+          }
+        }
+      }
+    }
+  }
+
+  /* Reset MsUsed flags if no explicit signalling was transmitted. Necessary for intensity coding.
+     PNS correlation signalling was mapped before calling CJointStereo_ApplyMS(). */
+  if (pJointStereoData->MsMaskPresent == 2) {
+    FDKmemclear(pJointStereoData->MsUsed, JointStereoMaximumBands * sizeof(UCHAR));
+  }
+}
+
+void CJointStereo_ApplyIS(
+        CAacDecoderChannelInfo *pAacDecoderChannelInfo[2],
+        const SHORT *pScaleFactorBandOffsets,
+        const UCHAR *pWindowGroupLength,
+        const int windowGroups,
+        const int scaleFactorBandsTransmitted,
+        const UINT CommonWindow
+        )
+{
+  CJointStereoData *pJointStereoData = &pAacDecoderChannelInfo[L]->pComData->jointStereoData;
+
+  for (int window=0,group=0; group<windowGroups; group++)
+  {
+    UCHAR *CodeBook;
+    SHORT *ScaleFactor;
+    UCHAR groupMask = 1 << group;
+
+    CodeBook = &pAacDecoderChannelInfo[R]->pDynData->aCodeBook[group*16];
+    ScaleFactor = &pAacDecoderChannelInfo[R]->pDynData->aScaleFactor[group*16];
+
+    for (int groupwin=0; groupwin<pWindowGroupLength[group]; groupwin++, window++)
+    {
+      FIXP_DBL *leftSpectrum, *rightSpectrum;
+      SHORT *leftScale = &pAacDecoderChannelInfo[L]->pDynData->aSfbScale[window*16];
+      SHORT *rightScale = &pAacDecoderChannelInfo[R]->pDynData->aSfbScale[window*16];
+      int band;
+
+      leftSpectrum = SPEC(pAacDecoderChannelInfo[L]->pSpectralCoefficient, window, pAacDecoderChannelInfo[L]->granuleLength);
+      rightSpectrum = SPEC(pAacDecoderChannelInfo[R]->pSpectralCoefficient, window, pAacDecoderChannelInfo[R]->granuleLength);
+
+      for (band=0; band<scaleFactorBandsTransmitted; band++)
+      {
+        if ((CodeBook [band] == INTENSITY_HCB) ||
+            (CodeBook [band] == INTENSITY_HCB2))
+        {
+          int bandScale = -(ScaleFactor [band] + 100) ;
+
+          int msb = bandScale >> 2 ;
+          int lsb = bandScale & 0x03 ;
+
+          /* exponent of MantissaTable[lsb][0] is 1, thus msb+1 below. */
+          FIXP_DBL scale = MantissaTable[lsb][0];
+
+          /* ISO/IEC 14496-3 Chapter 4.6.8.2.3 :
+             The use of intensity stereo coding is signaled by the use of the pseudo codebooks
+             INTENSITY_HCB and INTENSITY_HCB2 (15 and 14) only in the right channel of a
+             channel_pair_element() having a common ics_info() (common_window == 1). */
+          FDK_ASSERT(GetWindowSequence(&pAacDecoderChannelInfo[L]->icsInfo) == GetWindowSequence(&pAacDecoderChannelInfo[R]->icsInfo));
+          FDK_ASSERT(GetWindowShape(&pAacDecoderChannelInfo[L]->icsInfo) == GetWindowShape(&pAacDecoderChannelInfo[R]->icsInfo));
+
+          rightScale[band] = leftScale[band]+msb+1;
+
+          if (CommonWindow && (pJointStereoData->MsUsed[band] & groupMask))
+          {
+
+            if (CodeBook[band] == INTENSITY_HCB) /* _NOT_ in-phase */
+            {
+              scale = -scale ;
+            }
+          }
+          else
+          {
+            if (CodeBook[band] == INTENSITY_HCB2) /* out-of-phase */
+            {
+              scale = -scale ;
+            }
+          }
+
+          for (int index=pScaleFactorBandOffsets[band]; index<pScaleFactorBandOffsets[band+1]; index++)
+          {
+            rightSpectrum[index] = fMult(leftSpectrum[index],scale);
+          }
+        }
+      }
+    }
+  }
+}