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1 /* -----------------------------------------------------------------------------
2 Software License for The Fraunhofer FDK AAC Codec Library for Android
3 
4 © Copyright  1995 - 2019 Fraunhofer-Gesellschaft zur Förderung der angewandten
5 Forschung e.V. All rights reserved.
6 
7  1.    INTRODUCTION
8 The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software
9 that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding
10 scheme for digital audio. This FDK AAC Codec software is intended to be used on
11 a wide variety of Android devices.
12 
13 AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient
14 general perceptual audio codecs. AAC-ELD is considered the best-performing
15 full-bandwidth communications codec by independent studies and is widely
16 deployed. AAC has been standardized by ISO and IEC as part of the MPEG
17 specifications.
18 
19 Patent licenses for necessary patent claims for the FDK AAC Codec (including
20 those of Fraunhofer) may be obtained through Via Licensing
21 (www.vialicensing.com) or through the respective patent owners individually for
22 the purpose of encoding or decoding bit streams in products that are compliant
23 with the ISO/IEC MPEG audio standards. Please note that most manufacturers of
24 Android devices already license these patent claims through Via Licensing or
25 directly from the patent owners, and therefore FDK AAC Codec software may
26 already be covered under those patent licenses when it is used for those
27 licensed purposes only.
28 
29 Commercially-licensed AAC software libraries, including floating-point versions
30 with enhanced sound quality, are also available from Fraunhofer. Users are
31 encouraged to check the Fraunhofer website for additional applications
32 information and documentation.
33 
34 2.    COPYRIGHT LICENSE
35 
36 Redistribution and use in source and binary forms, with or without modification,
37 are permitted without payment of copyright license fees provided that you
38 satisfy the following conditions:
39 
40 You must retain the complete text of this software license in redistributions of
41 the FDK AAC Codec or your modifications thereto in source code form.
42 
43 You must retain the complete text of this software license in the documentation
44 and/or other materials provided with redistributions of the FDK AAC Codec or
45 your modifications thereto in binary form. You must make available free of
46 charge copies of the complete source code of the FDK AAC Codec and your
47 modifications thereto to recipients of copies in binary form.
48 
49 The name of Fraunhofer may not be used to endorse or promote products derived
50 from this library without prior written permission.
51 
52 You may not charge copyright license fees for anyone to use, copy or distribute
53 the FDK AAC Codec software or your modifications thereto.
54 
55 Your modified versions of the FDK AAC Codec must carry prominent notices stating
56 that you changed the software and the date of any change. For modified versions
57 of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android"
58 must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK
59 AAC Codec Library for Android."
60 
61 3.    NO PATENT LICENSE
62 
63 NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without
64 limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE.
65 Fraunhofer provides no warranty of patent non-infringement with respect to this
66 software.
67 
68 You may use this FDK AAC Codec software or modifications thereto only for
69 purposes that are authorized by appropriate patent licenses.
70 
71 4.    DISCLAIMER
72 
73 This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright
74 holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
75 including but not limited to the implied warranties of merchantability and
76 fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
77 CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary,
78 or consequential damages, including but not limited to procurement of substitute
79 goods or services; loss of use, data, or profits, or business interruption,
80 however caused and on any theory of liability, whether in contract, strict
81 liability, or tort (including negligence), arising in any way out of the use of
82 this software, even if advised of the possibility of such damage.
83 
84 5.    CONTACT INFORMATION
85 
86 Fraunhofer Institute for Integrated Circuits IIS
87 Attention: Audio and Multimedia Departments - FDK AAC LL
88 Am Wolfsmantel 33
89 91058 Erlangen, Germany
90 
91 www.iis.fraunhofer.de/amm
92 amm-info@iis.fraunhofer.de
93 ----------------------------------------------------------------------------- */
94 
95 /******************* Library for basic calculation routines ********************
96 
97    Author(s):   Manuel Jander, Josef Hoepfl, Youliy Ninov, Daniel Hagel
98 
99    Description: MDCT/MDST routines
100 
101 *******************************************************************************/
102 
103 #ifndef MDCT_H
104 #define MDCT_H
105 
106 #include "common_fix.h"
107 
108 #define MDCT_OUT_HEADROOM 2 /* Output additional headroom */
109 
110 #define PCM_OUT_BITS DFRACT_BITS
111 #define PCM_OUT_HEADROOM 8 /* Must have the same values as DMXH_HEADROOM */
112 
113 #define MDCT_OUTPUT_SCALE (-MDCT_OUT_HEADROOM + (DFRACT_BITS - PCM_OUT_BITS))
114 /* Refer to "Output word length" in ISO/IEC 14496-3:2008(E) 23.2.3.6 */
115 #define MDCT_OUTPUT_GAIN 16
116 
117 #define IMDCT_SCALE(x, s) \
118   SATURATE_RIGHT_SHIFT((x), ((s) + MDCT_OUTPUT_SCALE), PCM_OUT_BITS)
119 #define IMDCT_SCALE_DBL(x) (FIXP_DBL)(x)
120 #define IMDCT_SCALE_DBL_LSH1(x) SATURATE_LEFT_SHIFT_ALT((x), 1, DFRACT_BITS)
121 
122 #define MLT_FLAG_CURR_ALIAS_SYMMETRY 1
123 
124 typedef enum {
125   BLOCK_LONG = 0, /* normal long block */
126   BLOCK_START,    /* long start block */
127   BLOCK_SHORT,    /* 8 short blocks sequence */
128   BLOCK_STOP      /* long stop block*/
129 } BLOCK_TYPE;
130 
131 typedef enum { SHAPE_SINE = 0, SHAPE_KBD, SHAPE_LOL } WINDOW_SHAPE;
132 
133 /**
134  * \brief MDCT persistent data
135  */
136 typedef struct {
137   union {
138     FIXP_DBL *freq;
139     FIXP_DBL *time;
140   } overlap; /**< Pointer to overlap memory */
141 
142   const FIXP_WTP *prev_wrs; /**< pointer to previous right window slope  */
143   int prev_tl;              /**< previous transform length */
144   int prev_nr;              /**< previous right window offset */
145   int prev_fr;              /**< previous right window slope length */
146   int ov_offset;            /**< overlap time data fill level */
147   int ov_size;              /**< Overlap buffer size in words */
148 
149   int prevAliasSymmetry;
150   int prevPrevAliasSymmetry;
151 
152   FIXP_DBL *pFacZir;
153   FIXP_DBL *pAsymOvlp; /**< pointer to asymmetric overlap (used for stereo LPD
154                           transition) */
155 } mdct_t;
156 
157 typedef mdct_t *H_MDCT;
158 
159 /**
160  * \brief Initialize as valid MDCT handle
161  *
162  * \param hMdct handle of an allocated MDCT handle.
163  * \param overlap pointer to FIXP_DBL overlap buffer.
164  * \param overlapBufferSize size in FIXP_DBLs of the given overlap buffer.
165  */
166 void mdct_init(H_MDCT hMdct, FIXP_DBL *overlap, INT overlapBufferSize);
167 
168 /**
169  * \brief perform MDCT transform (time domain to frequency domain) with given
170  * parameters.
171  *
172  * \param hMdct handle of an allocated MDCT handle.
173  * \param pTimeData pointer to input time domain signal
174  * \param noInSamples number of input samples
175  * \param mdctData pointer to where the resulting MDCT spectrum will be stored
176  * into.
177  * \param nSpec number of spectra
178  * \param pMdctData_e pointer to the input data exponent. Updated accordingly on
179  * return for output data.
180  * \return number of input samples processed.
181  */
182 INT mdct_block(H_MDCT hMdct, const INT_PCM *pTimeData, const INT noInSamples,
183                FIXP_DBL *RESTRICT mdctData, const INT nSpec, const INT tl,
184                const FIXP_WTP *pRightWindowPart, const INT fr,
185                SHORT *pMdctData_e);
186 
187 /**
188  * \brief add/multiply 2/N transform gain and MPEG4 part 3 defined output gain
189  * (see definition of MDCT_OUTPUT_GAIN) to given mantissa factor and exponent.
190  * \param pGain pointer to the mantissa of a gain factor to be applied to IMDCT
191  * data.
192  * \param pExponent pointer to the exponent of a gain factor to be applied to
193  * IMDCT data.
194  * \param tl length of the IMDCT where the gain *pGain * (2 ^ *pExponent) will
195  * be applied to.
196  */
197 void imdct_gain(FIXP_DBL *pGain, int *pExponent, int tl);
198 
199 /**
200  * \brief drain buffered output samples into given buffer. Changes the MDCT
201  * state.
202  */
203 INT imdct_drain(H_MDCT hMdct, FIXP_DBL *pTimeData, INT nrSamplesRoom);
204 
205 /**
206  * \brief Copy overlap time domain data to given buffer. Does not change the
207  * MDCT state.
208  * \return number of actually copied samples (ov + nr).
209  */
210 INT imdct_copy_ov_and_nr(H_MDCT hMdct, FIXP_DBL *pTimeData, INT nrSamples);
211 
212 /**
213  * \brief Adapt MDCT parameters for non-matching window slopes.
214  * \param hMdct handle of an allocated MDCT handle.
215  * \param pfl pointer to left overlap window side length.
216  * \param pnl pointer to length of the left n part of the window.
217  * \param tl transform length.
218  * \param wls pointer to the left side overlap window coefficients.
219  * \param noOutSamples desired number of output samples.
220  */
221 void imdct_adapt_parameters(H_MDCT hMdct, int *pfl, int *pnl, int tl,
222                             const FIXP_WTP *wls, int noOutSamples);
223 
224 /**
225  * \brief perform several inverse MLT transforms (frequency domain to time
226  * domain) with given parameters.
227  *
228  * \param hMdct handle of an allocated MDCT handle.
229  * \param output pointer to where the output time domain signal will be stored
230  * into.
231  * \param spectrum pointer to the input MDCT spectra.
232  * \param scalefactors exponents of the input spectrum.
233  * \param nSpec number of MDCT spectrums.
234  * \param noOutSamples desired number of output samples.
235  * \param tl transform length.
236  * \param wls pointer to the left side overlap window coefficients.
237  * \param fl left overlap window side length.
238  * \param wrs pointer to the right side overlap window coefficients of all
239  * individual IMDCTs.
240  * \param fr right overlap window side length of all individual IMDCTs.
241  * \param gain factor to apply to output samples (if != 0).
242  * \param flags flags controlling the type of transform
243  * \return number of output samples returned.
244  */
245 INT imlt_block(H_MDCT hMdct, FIXP_DBL *output, FIXP_DBL *spectrum,
246                const SHORT scalefactor[], const INT nSpec,
247                const INT noOutSamples, const INT tl, const FIXP_WTP *wls,
248                INT fl, const FIXP_WTP *wrs, const INT fr, FIXP_DBL gain,
249                int flags);
250 
251 #endif /* MDCT_H */
252