/* -----------------------------------------------------------------------------
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Software License for The Fraunhofer FDK AAC Codec Library for Android
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© Copyright 1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten
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Forschung e.V. All rights reserved.
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1. INTRODUCTION
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The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software
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that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding
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scheme for digital audio. This FDK AAC Codec software is intended to be used on
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a wide variety of Android devices.
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AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient
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general perceptual audio codecs. AAC-ELD is considered the best-performing
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full-bandwidth communications codec by independent studies and is widely
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deployed. AAC has been standardized by ISO and IEC as part of the MPEG
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specifications.
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Patent licenses for necessary patent claims for the FDK AAC Codec (including
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those of Fraunhofer) may be obtained through Via Licensing
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(www.vialicensing.com) or through the respective patent owners individually for
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the purpose of encoding or decoding bit streams in products that are compliant
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with the ISO/IEC MPEG audio standards. Please note that most manufacturers of
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Android devices already license these patent claims through Via Licensing or
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directly from the patent owners, and therefore FDK AAC Codec software may
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already be covered under those patent licenses when it is used for those
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licensed purposes only.
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Commercially-licensed AAC software libraries, including floating-point versions
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with enhanced sound quality, are also available from Fraunhofer. Users are
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encouraged to check the Fraunhofer website for additional applications
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information and documentation.
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2. COPYRIGHT LICENSE
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Redistribution and use in source and binary forms, with or without modification,
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are permitted without payment of copyright license fees provided that you
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satisfy the following conditions:
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You must retain the complete text of this software license in redistributions of
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the FDK AAC Codec or your modifications thereto in source code form.
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You must retain the complete text of this software license in the documentation
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and/or other materials provided with redistributions of the FDK AAC Codec or
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your modifications thereto in binary form. You must make available free of
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charge copies of the complete source code of the FDK AAC Codec and your
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modifications thereto to recipients of copies in binary form.
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The name of Fraunhofer may not be used to endorse or promote products derived
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from this library without prior written permission.
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You may not charge copyright license fees for anyone to use, copy or distribute
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the FDK AAC Codec software or your modifications thereto.
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Your modified versions of the FDK AAC Codec must carry prominent notices stating
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that you changed the software and the date of any change. For modified versions
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of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android"
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must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK
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AAC Codec Library for Android."
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3. NO PATENT LICENSE
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NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without
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limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE.
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Fraunhofer provides no warranty of patent non-infringement with respect to this
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software.
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You may use this FDK AAC Codec software or modifications thereto only for
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purposes that are authorized by appropriate patent licenses.
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4. DISCLAIMER
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This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright
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holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
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including but not limited to the implied warranties of merchantability and
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fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary,
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or consequential damages, including but not limited to procurement of substitute
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goods or services; loss of use, data, or profits, or business interruption,
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however caused and on any theory of liability, whether in contract, strict
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liability, or tort (including negligence), arising in any way out of the use of
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this software, even if advised of the possibility of such damage.
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5. CONTACT INFORMATION
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Fraunhofer Institute for Integrated Circuits IIS
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Attention: Audio and Multimedia Departments - FDK AAC LL
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Am Wolfsmantel 33
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91058 Erlangen, Germany
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www.iis.fraunhofer.de/amm
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amm-info@iis.fraunhofer.de
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----------------------------------------------------------------------------- */
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/**************************** AAC decoder library ******************************
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Author(s): Josef Hoepfl
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Description: perceptual noise substitution tool
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*******************************************************************************/
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#include "aacdec_pns.h"
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#include "aac_ram.h"
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#include "aac_rom.h"
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#include "channelinfo.h"
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#include "block.h"
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#include "FDK_bitstream.h"
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#include "genericStds.h"
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#define NOISE_OFFSET 90 /* cf. ISO 14496-3 p. 175 */
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/*!
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\brief Reset InterChannel and PNS data
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The function resets the InterChannel and PNS data
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*/
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void CPns_ResetData(CPnsData *pPnsData,
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CPnsInterChannelData *pPnsInterChannelData) {
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FDK_ASSERT(pPnsData != NULL);
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FDK_ASSERT(pPnsInterChannelData != NULL);
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/* Assign pointer always, since pPnsData is not persistent data */
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pPnsData->pPnsInterChannelData = pPnsInterChannelData;
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pPnsData->PnsActive = 0;
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pPnsData->CurrentEnergy = 0;
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FDKmemclear(pPnsData->pnsUsed, (8 * 16) * sizeof(UCHAR));
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FDKmemclear(pPnsInterChannelData->correlated, (8 * 16) * sizeof(UCHAR));
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}
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/*!
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\brief Update PNS noise generator state.
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The function sets the seed for PNS noise generation.
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It can be used to link two or more channels in terms of PNS.
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*/
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void CPns_UpdateNoiseState(CPnsData *pPnsData, INT *currentSeed,
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INT *randomSeed) {
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/* use pointer because seed has to be
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same, left and right channel ! */
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pPnsData->currentSeed = currentSeed;
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pPnsData->randomSeed = randomSeed;
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}
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/*!
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\brief Indicates if PNS is used
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The function returns a value indicating whether PNS is used or not
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acordding to the noise energy
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\return PNS used
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*/
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int CPns_IsPnsUsed(const CPnsData *pPnsData, const int group, const int band) {
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unsigned pns_band = group * 16 + band;
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return pPnsData->pnsUsed[pns_band] & (UCHAR)1;
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}
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/*!
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\brief Set correlation
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The function activates the noise correlation between the channel pair
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*/
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void CPns_SetCorrelation(CPnsData *pPnsData, const int group, const int band,
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const int outofphase) {
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CPnsInterChannelData *pInterChannelData = pPnsData->pPnsInterChannelData;
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unsigned pns_band = group * 16 + band;
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pInterChannelData->correlated[pns_band] = (outofphase) ? 3 : 1;
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}
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/*!
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\brief Indicates if correlation is used
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The function indicates if the noise correlation between the channel pair
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is activated
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\return PNS is correlated
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*/
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static int CPns_IsCorrelated(const CPnsData *pPnsData, const int group,
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const int band) {
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CPnsInterChannelData *pInterChannelData = pPnsData->pPnsInterChannelData;
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unsigned pns_band = group * 16 + band;
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return (pInterChannelData->correlated[pns_band] & 0x01) ? 1 : 0;
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}
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/*!
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\brief Indicates if correlated out of phase mode is used.
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The function indicates if the noise correlation between the channel pair
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is activated in out-of-phase mode.
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\return PNS is out-of-phase
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*/
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static int CPns_IsOutOfPhase(const CPnsData *pPnsData, const int group,
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const int band) {
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CPnsInterChannelData *pInterChannelData = pPnsData->pPnsInterChannelData;
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unsigned pns_band = group * 16 + band;
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return (pInterChannelData->correlated[pns_band] & 0x02) ? 1 : 0;
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}
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/*!
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\brief Read PNS information
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The function reads the PNS information from the bitstream
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*/
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void CPns_Read(CPnsData *pPnsData, HANDLE_FDK_BITSTREAM bs,
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const CodeBookDescription *hcb, SHORT *pScaleFactor,
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UCHAR global_gain, int band, int group /* = 0 */) {
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int delta;
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UINT pns_band = group * 16 + band;
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if (pPnsData->PnsActive) {
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/* Next PNS band case */
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delta = CBlock_DecodeHuffmanWord(bs, hcb) - 60;
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} else {
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/* First PNS band case */
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int noiseStartValue = FDKreadBits(bs, 9);
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delta = noiseStartValue - 256;
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pPnsData->PnsActive = 1;
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pPnsData->CurrentEnergy = global_gain - NOISE_OFFSET;
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}
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pPnsData->CurrentEnergy += delta;
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pScaleFactor[pns_band] = pPnsData->CurrentEnergy;
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pPnsData->pnsUsed[pns_band] = 1;
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}
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/**
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* \brief Generate a vector of noise of given length. The noise values are
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* scaled in order to yield a noise energy of 1.0
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* \param spec pointer to were the noise values will be written to.
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* \param size amount of noise values to be generated.
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* \param pRandomState pointer to the state of the random generator being used.
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* \return exponent of generated noise vector.
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*/
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static int GenerateRandomVector(FIXP_DBL *RESTRICT spec, int size,
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int *pRandomState) {
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int i, invNrg_e = 0, nrg_e = 0;
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FIXP_DBL invNrg_m, nrg_m = FL2FXCONST_DBL(0.0f);
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FIXP_DBL *RESTRICT ptr = spec;
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int randomState = *pRandomState;
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#define GEN_NOISE_NRG_SCALE 7
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/* Generate noise and calculate energy. */
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for (i = 0; i < size; i++) {
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randomState =
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(((INT64)1664525 * randomState) + (INT64)1013904223) & 0xFFFFFFFF;
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nrg_m = fPow2AddDiv2(nrg_m, (FIXP_DBL)randomState >> GEN_NOISE_NRG_SCALE);
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*ptr++ = (FIXP_DBL)randomState;
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}
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nrg_e = GEN_NOISE_NRG_SCALE * 2 + 1;
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/* weight noise with = 1 / sqrt_nrg; */
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invNrg_m = invSqrtNorm2(nrg_m << 1, &invNrg_e);
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invNrg_e += -((nrg_e - 1) >> 1);
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for (i = size; i--;) {
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spec[i] = fMult(spec[i], invNrg_m);
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}
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/* Store random state */
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*pRandomState = randomState;
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return invNrg_e;
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}
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static void ScaleBand(FIXP_DBL *RESTRICT spec, int size, int scaleFactor,
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int specScale, int noise_e, int out_of_phase) {
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int i, shift, sfExponent;
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FIXP_DBL sfMatissa;
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/* Get gain from scale factor value = 2^(scaleFactor * 0.25) */
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sfMatissa = MantissaTable[scaleFactor & 0x03][0];
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/* sfExponent = (scaleFactor >> 2) + ExponentTable[scaleFactor & 0x03][0]; */
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/* Note: ExponentTable[scaleFactor & 0x03][0] is always 1. */
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sfExponent = (scaleFactor >> 2) + 1;
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if (out_of_phase != 0) {
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sfMatissa = -sfMatissa;
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}
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/* +1 because of fMultDiv2 below. */
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shift = sfExponent - specScale + 1 + noise_e;
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/* Apply gain to noise values */
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if (shift >= 0) {
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shift = fixMin(shift, DFRACT_BITS - 1);
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for (i = size; i-- != 0;) {
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spec[i] = fMultDiv2(spec[i], sfMatissa) << shift;
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}
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} else {
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shift = fixMin(-shift, DFRACT_BITS - 1);
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for (i = size; i-- != 0;) {
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spec[i] = fMultDiv2(spec[i], sfMatissa) >> shift;
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}
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}
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}
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/*!
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\brief Apply PNS
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The function applies PNS (i.e. it generates noise) on the bands
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flagged as noisy bands
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*/
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void CPns_Apply(const CPnsData *pPnsData, const CIcsInfo *pIcsInfo,
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SPECTRAL_PTR pSpectrum, const SHORT *pSpecScale,
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const SHORT *pScaleFactor,
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const SamplingRateInfo *pSamplingRateInfo,
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const INT granuleLength, const int channel) {
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if (pPnsData->PnsActive) {
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const short *BandOffsets =
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GetScaleFactorBandOffsets(pIcsInfo, pSamplingRateInfo);
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int ScaleFactorBandsTransmitted = GetScaleFactorBandsTransmitted(pIcsInfo);
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for (int window = 0, group = 0; group < GetWindowGroups(pIcsInfo);
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group++) {
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for (int groupwin = 0; groupwin < GetWindowGroupLength(pIcsInfo, group);
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groupwin++, window++) {
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FIXP_DBL *spectrum = SPEC(pSpectrum, window, granuleLength);
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for (int band = 0; band < ScaleFactorBandsTransmitted; band++) {
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if (CPns_IsPnsUsed(pPnsData, group, band)) {
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UINT pns_band = window * 16 + band;
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int bandWidth = BandOffsets[band + 1] - BandOffsets[band];
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int noise_e;
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FDK_ASSERT(bandWidth >= 0);
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if (channel > 0 && CPns_IsCorrelated(pPnsData, group, band)) {
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noise_e =
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GenerateRandomVector(spectrum + BandOffsets[band], bandWidth,
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&pPnsData->randomSeed[pns_band]);
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} else {
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pPnsData->randomSeed[pns_band] = *pPnsData->currentSeed;
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noise_e = GenerateRandomVector(spectrum + BandOffsets[band],
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bandWidth, pPnsData->currentSeed);
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}
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int outOfPhase = CPns_IsOutOfPhase(pPnsData, group, band);
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ScaleBand(spectrum + BandOffsets[band], bandWidth,
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pScaleFactor[group * 16 + band], pSpecScale[window],
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noise_e, outOfPhase);
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}
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}
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}
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}
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}
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}
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