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The Android Open Source Project
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libFDK/include/mdct.h
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libFDK/include/mdct.h
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/* -----------------------------------------------------------------------------------------------------------
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Software License for The Fraunhofer FDK AAC Codec Library for Android
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<EFBFBD> Copyright 1995 - 2012 Fraunhofer-Gesellschaft zur F<>rderung der angewandten Forschung e.V.
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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 that implements
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the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio.
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This FDK AAC Codec software is intended to be used on 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 general perceptual
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audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by
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independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part
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of the MPEG specifications.
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Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer)
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may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners
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individually for the purpose of encoding or decoding bit streams in products that are compliant with
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the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license
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these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec
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software may already be covered under those patent licenses when it is used for those licensed purposes only.
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Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality,
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are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional
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applications 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, are permitted without
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payment of copyright license fees provided that you satisfy the following conditions:
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You must retain the complete text of this software license in redistributions of the FDK AAC Codec or
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your modifications thereto in source code form.
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You must retain the complete text of this software license in the documentation and/or other materials
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provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form.
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You must make available free of 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 from this library without
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prior written permission.
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You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec
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software or your modifications thereto.
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Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software
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and the date of any change. For modified versions of the FDK AAC Codec, the term
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"Fraunhofer FDK AAC Codec Library for Android" must be replaced by the term
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"Third-Party Modified Version of the Fraunhofer FDK 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 limitation the patents of Fraunhofer,
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ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with
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respect to this software.
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You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized
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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 holders and contributors
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"AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, including but not limited to the implied warranties
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of merchantability and 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, or consequential damages,
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including but not limited to procurement of substitute goods or services; loss of use, data, or profits,
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or business interruption, 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 this software, even if
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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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/*************************** Fraunhofer IIS FDK Tools **********************
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Author(s): Manuel Jander, Josef Hoepfl
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Description: MDCT routines
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******************************************************************************/
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#ifndef __MDCT_H__
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#define __MDCT_H__
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#include "common_fix.h"
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#define MDCT_OUT_HEADROOM 2 /* Output additional headroom */
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#define MDCT_OUTPUT_SCALE (DFRACT_BITS-SAMPLE_BITS-MDCT_OUT_HEADROOM)
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/* Refer to "Output word length" in ISO/IEC 14496-3:2008(E) 23.2.3.6 */
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#define MDCT_OUTPUT_GAIN 16
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#if (SAMPLE_BITS == DFRACT_BITS)
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#define IMDCT_SCALE(x) (INT_PCM)SATURATE_LEFT_SHIFT(x, -MDCT_OUTPUT_SCALE, SAMPLE_BITS)
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#else
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#define IMDCT_SCALE(x) (INT_PCM)SATURATE_RIGHT_SHIFT(x, MDCT_OUTPUT_SCALE, SAMPLE_BITS)
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#endif
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#define IMDCT_SCALE_DBL(x) (FIXP_DBL)(x)
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/**
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* \brief MDCT persistent data
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*/
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typedef struct {
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union {
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FIXP_DBL *freq;
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FIXP_DBL *time;
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} overlap; /**< Pointer to overlap memory */
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const FIXP_WTP *prev_wrs; /**< pointer to previous right window slope */
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int prev_tl; /**< previous tranform length */
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int prev_nr; /**< previous right window offset */
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int prev_fr; /**< previous right window slope length */
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int ov_offset; /**< overlap time data fill level */
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int ov_size; /**< Overlap buffer size in words */
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} mdct_t;
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typedef mdct_t* H_MDCT;
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/**
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* \brief Initialize as valid MDCT handle
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*
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* \param hMdct handle of an allocated MDCT handle.
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* \param overlap pointer to FIXP_DBL overlap buffer.
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* \param overlapBufferSize size in FIXP_DBLs of the given overlap buffer.
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* \return void
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*/
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void mdct_init( H_MDCT hMdct,
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FIXP_DBL *overlap,
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INT overlapBufferSize );
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/**
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* \brief perform MDCT transform (time domain to frequency domain) with given parameters.
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*
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* \param hMdct handle of an allocated MDCT handle.
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* \param spectrum pointer to where the resulting MDCT spectrum will be stored into.
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* \param scalefactor pointer to the input scale shift value. Updated accordingly on return.
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* \param input pointer to input time domain signal
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* \param tl transformation length.
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* \param nr right window slope offset (amount of window coefficients assumed to be 1.0)
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* \param fr right overlap window slope length
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* \param wrs pointer to the right side overlap window coefficients.
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* \return number of input samples processed.
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*/
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INT mdct_block(
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H_MDCT hMdct,
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FIXP_DBL *spectrum,
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INT *scalefactor,
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INT_PCM *input,
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INT tl,
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INT nr,
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INT fr,
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const FIXP_WTB *wrs );
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/**
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* \brief add/multiply 2/N transform gain and MPEG4 part 3 defined output gain (see definition
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* of MDCT_OUTPUT_GAIN) to given mantissa factor and exponent.
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* \param pGain pointer to the mantissa of a gain factor to be applied to IMDCT data.
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* \param pExponent pointer to the exponent of a gain factor to be applied to IMDCT data.
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* \param tl length of the IMDCT where the gain *pGain * (2 ^ *pExponent) will be applied to.
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*/
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void imdct_gain(
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FIXP_DBL *pGain,
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int *pExponent,
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int tl
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);
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/**
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* \brief drain buffered output samples into given buffer. Changes the MDCT state.
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*/
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INT imdct_drain(
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H_MDCT hMdct,
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FIXP_DBL * pTimeData,
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INT nrSamplesRoom
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);
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/**
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* \brief Copy overlap time domain data to given buffer. Does not change the MDCT state.
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* \return number of actually copied samples (ov + nr).
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*/
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INT imdct_copy_ov_and_nr(
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H_MDCT hMdct,
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FIXP_DBL * pTimeData,
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INT nrSamples
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);
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/**
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* \brief Adapt MDCT parameters for non-matching window slopes.
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* \param hMdct handle of an allocated MDCT handle.
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* \param pfl pointer to left overlap window side length.
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* \param pnl pointer to length of the left n part of the window.
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* \param tl transform length.
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* \param wls pointer to the left side overlap window coefficients.
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* \param noOutSamples desired number of output samples.
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*/
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void imdct_adapt_parameters(H_MDCT hMdct, int *pfl, int *pnl, int tl, const FIXP_WTP *wls, int noOutSamples);
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/**
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* \brief perform several inverse MDCT transforms (frequency domain to time domain) with given parameters.
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*
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* \param hMdct handle of an allocated MDCT handle.
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* \param output pointer to where the output time domain signal will be stored into.
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* \param stride the stride factor for accessing time domain samples in output.
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* \param spectrum pointer to the input MDCT spectra.
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* \param scalefactors scale shift values of the input spectrum.
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* \param nSpec number of MDCT spectrums.
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* \param noOutSamples desired number of output samples.
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* \param tl transform length.
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* \param wls pointer to the left side overlap window coefficients.
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* \param fl left overlap window side length.
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* \param wrs pointer to the right side overlap window coefficients of all individual IMDCTs.
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* \param fr right overlap window side length of all individual IMDCTs.
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* \param gain factor to apply to output samples (if != 0).
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* \return number of output samples returned.
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*/
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INT imdct_block(
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H_MDCT hMdct,
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FIXP_DBL *output,
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FIXP_DBL *spectrum,
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const SHORT scalefactor[],
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const INT nSpec,
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const INT noOutSamples,
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const INT tl,
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const FIXP_WTP *wls,
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INT fl,
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const FIXP_WTP *wrs,
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const INT fr,
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FIXP_DBL gain );
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#endif /* __MDCT_H__ */
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