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Diffstat (limited to 'libAACdec/src/stereo.cpp')
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diff --git a/libAACdec/src/stereo.cpp b/libAACdec/src/stereo.cpp new file mode 100644 index 0000000..79ebc7d --- /dev/null +++ b/libAACdec/src/stereo.cpp @@ -0,0 +1,297 @@ + +/* ----------------------------------------------------------------------------------------------------------- +Software License for The Fraunhofer FDK AAC Codec Library for Android + +© Copyright 1995 - 2012 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 +----------------------------------------------------------------------------------------------------------- */ + +/***************************** MPEG-4 AAC Decoder ************************** + + Author(s): Josef Hoepfl + Description: joint stereo processing + +******************************************************************************/ + +#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); + } + } + } + } + } +} |