xref: /aosp_15_r20/external/aac/libAACenc/src/transform.h (revision e54365361535b070c2db7374cec45c159c7d0e7a)

/* -----------------------------------------------------------------------------
Software License for The Fraunhofer FDK AAC Codec Library for Android

© Copyright  1995 - 2018 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
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charge copies of the complete source code of the FDK AAC Codec and your
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Fraunhofer provides no warranty of patent non-infringement with respect to this
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You may use this FDK AAC Codec software or modifications thereto only for
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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,
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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
[email protected]
----------------------------------------------------------------------------- */

/**************************** AAC encoder library ******************************

   Author(s):   M. Werner

   Description: MDCT Transform

*******************************************************************************/

#ifndef TRANSFORM_H
#define TRANSFORM_H

#include "mdct.h"
#include "common_fix.h"

#define WTS0 1
#define WTS1 0
#define WTS2 -2

/**
 * \brief: Performe MDCT transform of time domain data.
 * \param timeData pointer to time domain input signal.
 * \param mdctData pointer to store frequency domain output data.
 * \param blockType index indicating the type of block. Either
 *        LONG_WINDOW, START_WINDOW, SHORT_WINDOW or STOP_WINDOW.
 * \param windowShape index indicating the window slope type to be used.
 *        Values allowed are either SINE_WINDOW or KBD_WINDOW.
 * \param previndowShape index indicating the window slope type used
 *        in the last frame.
 *        Values allowed are either SINE_WINDOW or KBD_WINDOW.
 * \param frameLength length of the block. Either 1024 or 960.
 * \param mdctData_e pointer to an INT where the exponent of the frequency
 *        domain output data is stored into.
 * \param filterType xxx
 * \return 0 in case of success, non-zero in case of error (inconsistent
 * parameters).
 */
INT FDKaacEnc_Transform_Real(const INT_PCM* pTimeData,
                             FIXP_DBL* RESTRICT mdctData, const INT blockType,
                             const INT windowShape, INT* prevWindowShape,
                             H_MDCT mdctPers, const INT frameLength,
                             INT* pMdctData_e, INT filterType);

/**
 * \brief: Performe ELD filterbnank transform of time domain data.
 * \param timeData pointer to time domain input signal.
 * \param mdctData pointer to store frequency domain output data.
 * \param blockType index indicating the type of block. Either
 *        LONG_WINDOW, START_WINDOW, SHORT_WINDOW or STOP_WINDOW.
 * \param windowShape index indicating the window slope type to be used.
 *        Values allowed are either SINE_WINDOW or KBD_WINDOW.
 * \param previndowShape index indicating the window slope type used
 *        in the last frame.
 *        Values allowed are either SINE_WINDOW or KBD_WINDOW.
 * \param frameLength length of the block. Either 1024 or 960.
 * \param mdctData_e pointer to an INT where the exponent of the frequency
 *        domain output data is stored into.
 * \param filterType xxx
 * \param overlapAddBuffer overlap add buffer for overlap of ELD filterbank
 * \return 0 in case of success, non-zero in case of error (inconsistent
 * parameters).
 */
INT FDKaacEnc_Transform_Real_Eld(const INT_PCM* pTimeData,
                                 FIXP_DBL* RESTRICT mdctData,
                                 const INT blockType, const INT windowShape,
                                 INT* prevWindowShape, const INT frameLength,
                                 INT* mdctData_e, INT filterType,
                                 FIXP_DBL* RESTRICT overlapAddBuffer);

#endif /* #!defined (TRANSFORM_H) */