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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);
+ }
+ }
+ }
+ }
+ }
+}
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