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      1 
      2 /* -----------------------------------------------------------------------------------------------------------
      3 Software License for The Fraunhofer FDK AAC Codec Library for Android
      4 
      5  Copyright  1995 - 2012 Fraunhofer-Gesellschaft zur Frderung der angewandten Forschung e.V.
      6   All rights reserved.
      7 
      8  1.    INTRODUCTION
      9 The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements
     10 the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio.
     11 This FDK AAC Codec software is intended to be used on a wide variety of Android devices.
     12 
     13 AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual
     14 audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by
     15 independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part
     16 of the MPEG specifications.
     17 
     18 Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer)
     19 may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners
     20 individually for the purpose of encoding or decoding bit streams in products that are compliant with
     21 the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license
     22 these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec
     23 software may already be covered under those patent licenses when it is used for those licensed purposes only.
     24 
     25 Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality,
     26 are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional
     27 applications information and documentation.
     28 
     29 2.    COPYRIGHT LICENSE
     30 
     31 Redistribution and use in source and binary forms, with or without modification, are permitted without
     32 payment of copyright license fees provided that you satisfy the following conditions:
     33 
     34 You must retain the complete text of this software license in redistributions of the FDK AAC Codec or
     35 your modifications thereto in source code form.
     36 
     37 You must retain the complete text of this software license in the documentation and/or other materials
     38 provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form.
     39 You must make available free of charge copies of the complete source code of the FDK AAC Codec and your
     40 modifications thereto to recipients of copies in binary form.
     41 
     42 The name of Fraunhofer may not be used to endorse or promote products derived from this library without
     43 prior written permission.
     44 
     45 You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec
     46 software or your modifications thereto.
     47 
     48 Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software
     49 and the date of any change. For modified versions of the FDK AAC Codec, the term
     50 "Fraunhofer FDK AAC Codec Library for Android" must be replaced by the term
     51 "Third-Party Modified Version of the Fraunhofer FDK AAC Codec Library for Android."
     52 
     53 3.    NO PATENT LICENSE
     54 
     55 NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer,
     56 ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with
     57 respect to this software.
     58 
     59 You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized
     60 by appropriate patent licenses.
     61 
     62 4.    DISCLAIMER
     63 
     64 This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright holders and contributors
     65 "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, including but not limited to the implied warranties
     66 of merchantability and fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
     67 CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages,
     68 including but not limited to procurement of substitute goods or services; loss of use, data, or profits,
     69 or business interruption, however caused and on any theory of liability, whether in contract, strict
     70 liability, or tort (including negligence), arising in any way out of the use of this software, even if
     71 advised of the possibility of such damage.
     72 
     73 5.    CONTACT INFORMATION
     74 
     75 Fraunhofer Institute for Integrated Circuits IIS
     76 Attention: Audio and Multimedia Departments - FDK AAC LL
     77 Am Wolfsmantel 33
     78 91058 Erlangen, Germany
     79 
     80 www.iis.fraunhofer.de/amm
     81 amm-info (at) iis.fraunhofer.de
     82 ----------------------------------------------------------------------------------------------------------- */
     83 
     84 /***************************  Fraunhofer IIS FDK Tools  **********************
     85 
     86    Author(s):   Manuel Jander, Josef Hoepfl
     87    Description: MDCT routines
     88 
     89 ******************************************************************************/
     90 
     91 #ifndef __MDCT_H__
     92 #define __MDCT_H__
     93 
     94 
     95 
     96 #include "common_fix.h"
     97 
     98 #define MDCT_OUT_HEADROOM     2 /* Output additional headroom */
     99 #define MDCT_OUTPUT_SCALE    (DFRACT_BITS-SAMPLE_BITS-MDCT_OUT_HEADROOM)
    100 /* Refer to "Output word length" in ISO/IEC 14496-3:2008(E) 23.2.3.6 */
    101 #define MDCT_OUTPUT_GAIN      16
    102 
    103 #if (SAMPLE_BITS == DFRACT_BITS)
    104 #define IMDCT_SCALE(x) (INT_PCM)SATURATE_LEFT_SHIFT(x, -MDCT_OUTPUT_SCALE, SAMPLE_BITS)
    105 #else
    106 #define IMDCT_SCALE(x) (INT_PCM)SATURATE_RIGHT_SHIFT(x, MDCT_OUTPUT_SCALE, SAMPLE_BITS)
    107 #endif
    108 #define IMDCT_SCALE_DBL(x) (FIXP_DBL)(x)
    109 
    110 /**
    111  * \brief MDCT persistent data
    112  */
    113 typedef struct {
    114   union {
    115     FIXP_DBL *freq;
    116     FIXP_DBL *time;
    117   } overlap;                       /**< Pointer to overlap memory */
    118 
    119   const FIXP_WTP *prev_wrs;        /**< pointer to previous right window slope  */
    120   int prev_tl;                     /**< previous tranform length */
    121   int prev_nr;                     /**< previous right window offset */
    122   int prev_fr;                     /**< previous right window slope length */
    123   int ov_offset;                   /**< overlap time data fill level */
    124   int ov_size;                     /**< Overlap buffer size in words */
    125 
    126 } mdct_t;
    127 
    128 typedef mdct_t* H_MDCT;
    129 
    130 /**
    131  * \brief Initialize as valid MDCT handle
    132  *
    133  * \param hMdct handle of an allocated MDCT handle.
    134  * \param overlap pointer to FIXP_DBL overlap buffer.
    135  * \param overlapBufferSize size in FIXP_DBLs of the given overlap buffer.
    136  * \return void
    137  */
    138 void mdct_init( H_MDCT hMdct,
    139                 FIXP_DBL *overlap,
    140                 INT overlapBufferSize );
    141 
    142 /**
    143  * \brief perform MDCT transform (time domain to frequency domain) with given parameters.
    144  *
    145  * \param hMdct handle of an allocated MDCT handle.
    146  * \param spectrum pointer to where the resulting MDCT spectrum will be stored into.
    147  * \param scalefactor pointer to the input scale shift value. Updated accordingly on return.
    148  * \param input pointer to input time domain signal
    149  * \param tl transformation length.
    150  * \param nr right window slope offset (amount of window coefficients assumed to be 1.0)
    151  * \param fr right overlap window slope length
    152  * \param wrs pointer to the right side overlap window coefficients.
    153  * \return number of input samples processed.
    154  */
    155 INT  mdct_block(
    156         H_MDCT hMdct,
    157         FIXP_DBL *spectrum,
    158         INT *scalefactor,
    159         INT_PCM *input,
    160         INT tl,
    161         INT nr,
    162         INT fr,
    163         const FIXP_WTB *wrs );
    164 
    165 
    166 /**
    167  * \brief add/multiply 2/N transform gain and MPEG4 part 3 defined output gain (see definition
    168  *        of MDCT_OUTPUT_GAIN) to given mantissa factor and exponent.
    169  * \param pGain pointer to the mantissa of a gain factor to be applied to IMDCT data.
    170  * \param pExponent pointer to the exponent of a gain factor to be applied to IMDCT data.
    171  * \param tl length of the IMDCT where the gain *pGain * (2 ^ *pExponent) will be applied to.
    172  */
    173 void imdct_gain(
    174         FIXP_DBL *pGain,
    175         int *pExponent,
    176         int tl
    177         );
    178 
    179 /**
    180  * \brief drain buffered output samples into given buffer. Changes the MDCT state.
    181  */
    182 INT imdct_drain(
    183         H_MDCT hMdct,
    184         FIXP_DBL * pTimeData,
    185         INT nrSamplesRoom
    186         );
    187 
    188 
    189 /**
    190  * \brief Copy overlap time domain data to given buffer. Does not change the MDCT state.
    191  * \return number of actually copied samples (ov + nr).
    192  */
    193 INT imdct_copy_ov_and_nr(
    194         H_MDCT hMdct,
    195         FIXP_DBL * pTimeData,
    196         INT nrSamples
    197         );
    198 
    199 /**
    200  * \brief Adapt MDCT parameters for non-matching window slopes.
    201  * \param hMdct handle of an allocated MDCT handle.
    202  * \param pfl pointer to left overlap window side length.
    203  * \param pnl pointer to length of the left n part of the window.
    204  * \param tl transform length.
    205  * \param wls pointer to the left side overlap window coefficients.
    206  * \param noOutSamples desired number of output samples.
    207  */
    208 void imdct_adapt_parameters(H_MDCT hMdct, int *pfl, int *pnl, int tl, const FIXP_WTP *wls, int noOutSamples);
    209 
    210 /**
    211  * \brief perform several inverse MDCT transforms (frequency domain to time domain) with given parameters.
    212  *
    213  * \param hMdct handle of an allocated MDCT handle.
    214  * \param output pointer to where the output time domain signal will be stored into.
    215  * \param stride the stride factor for accessing time domain samples in output.
    216  * \param spectrum pointer to the input MDCT spectra.
    217  * \param scalefactors scale shift values of the input spectrum.
    218  * \param nSpec number of MDCT spectrums.
    219  * \param noOutSamples desired number of output samples.
    220  * \param tl transform length.
    221  * \param wls pointer to the left side overlap window coefficients.
    222  * \param fl left overlap window side length.
    223  * \param wrs pointer to the right side overlap window coefficients of all individual IMDCTs.
    224  * \param fr right overlap window side length of all individual IMDCTs.
    225  * \param gain factor to apply to output samples (if != 0).
    226  * \return number of output samples returned.
    227  */
    228 INT  imdct_block(
    229         H_MDCT hMdct,
    230         FIXP_DBL *output,
    231         FIXP_DBL *spectrum,
    232         const SHORT scalefactor[],
    233         const INT nSpec,
    234         const INT noOutSamples,
    235         const INT tl,
    236         const FIXP_WTP *wls,
    237         INT fl,
    238         const FIXP_WTP *wrs,
    239         const INT fr,
    240         FIXP_DBL gain );
    241 
    242 
    243 #endif /* __MDCT_H__ */
    244