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1 /* -----------------------------------------------------------------------------
2 Software License for The Fraunhofer FDK AAC Codec Library for Android
3 
4 © Copyright  1995 - 2018 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
98 
99    Description: LPC related functions
100 
101 *******************************************************************************/
102 
103 #ifndef FDK_LPC_H
104 #define FDK_LPC_H
105 
106 #include "common_fix.h"
107 
108 #define LPC_MAX_ORDER 24
109 
110 /*
111  * Experimental solution for lattice filter substitution.
112  * LPC_SYNTHESIS_IIR macro must be activated in aacdec_tns.cpp.
113  * When LPC_SYNTHESIS_IIR enabled, there will be a substitution of the default
114  * lpc synthesis lattice filter by an IIR synthesis filter (with a conversionof
115  * the filter coefs). LPC_TNS related macros are intended to implement the data
116  * types used by the CLpc_Synthesis variant which is used for this solution.
117  * */
118 
119 /* #define LPC_TNS_LOWER_PRECISION */
120 
121 typedef FIXP_DBL FIXP_LPC_TNS;
122 #define FX_DBL2FX_LPC_TNS(x) (x)
123 #define FX_DBL2FXCONST_LPC_TNS(x) (x)
124 #define FX_LPC_TNS2FX_DBL(x) (x)
125 #define FL2FXCONST_LPC_TNS(val) FL2FXCONST_DBL(val)
126 #define MAXVAL_LPC_TNS MAXVAL_DBL
127 
128 typedef FIXP_SGL FIXP_LPC;
129 #define FX_DBL2FX_LPC(x) FX_DBL2FX_SGL((FIXP_DBL)(x))
130 #define FX_DBL2FXCONST_LPC(x) FX_DBL2FXCONST_SGL(x)
131 #define FX_LPC2FX_DBL(x) FX_SGL2FX_DBL(x)
132 #define FL2FXCONST_LPC(val) FL2FXCONST_SGL(val)
133 #define MAXVAL_LPC MAXVAL_SGL
134 
135 /**
136  * \brief Obtain residual signal through LPC analysis.
137  * \param signal pointer to buffer holding signal to be analysed. Residual is
138  * returned there (in place)
139  * \param signal_size the size of the input data in pData
140  * \param lpcCoeff_m the LPC filter coefficient mantissas
141  * \param lpcCoeff_e the LPC filter coefficient exponent
142  * \param order the LPC filter order (size of coeff)
143  * \param filtState Pointer to state buffer of size order
144  * \param filtStateIndex pointer to state index storage
145  */
146 void CLpc_Analysis(FIXP_DBL signal[], const int signal_size,
147                    const FIXP_LPC lpcCoeff_m[], const int lpcCoeff_e,
148                    const int order, FIXP_DBL *filtState, int *filtStateIndex);
149 
150 /**
151  * \brief Synthesize signal fom residual through LPC synthesis, using LP
152  * coefficients.
153  * \param signal pointer to buffer holding the residual signal. The synthesis is
154  * returned there (in place)
155  * \param signal_size the size of the input data in pData
156  * \param inc buffer traversal increment for signal
157  * \param coeff the LPC filter coefficients
158  * \param coeff_e exponent of coeff
159  * \param order the LPC filter order (size of coeff)
160  * \param state state buffer of size LPC_MAX_ORDER
161  * \param pStateIndex pointer to state index storage
162  */
163 void CLpc_Synthesis(FIXP_DBL *signal, const int signal_size, const int signal_e,
164                     const int inc, const FIXP_LPC_TNS *lpcCoeff_m,
165                     const int lpcCoeff_e, const int order, FIXP_DBL *state,
166                     int *pStateIndex);
167 void CLpc_Synthesis(FIXP_DBL *signal, const int signal_size, const int signal_e,
168                     const int inc, const FIXP_LPC coeff[], const int coeff_e,
169                     const int order, FIXP_DBL *filtState, int *pStateIndex);
170 
171 /**
172  * \brief Synthesize signal fom residual through LPC synthesis, using ParCor
173  * coefficients. The algorithm assumes a filter gain of max 1.0. If the filter
174  * gain is higher, this must be accounted into the values of signal_e
175  * and/or signal_e_out to avoid overflows.
176  * \param signal pointer to buffer holding the residual signal. The synthesis is
177  * returned there (in place)
178  * \param signal_size the size of the input data in pData
179  * \param inc buffer traversal increment for signal
180  * \param coeff the LPC filter coefficients
181  * \param coeff_e exponent of coeff
182  * \param order the LPC filter order (size of coeff)
183  * \param state state buffer of size LPC_MAX_ORDER
184  */
185 void CLpc_SynthesisLattice(FIXP_DBL *signal, const int signal_size,
186                            const int signal_e, const int signal_e_out,
187                            const int inc, const FIXP_SGL *coeff,
188                            const int order, FIXP_DBL *state);
189 
190 void CLpc_SynthesisLattice(FIXP_DBL *RESTRICT signal, const int signal_size,
191                            const int signal_e, const int signal_e_out,
192                            const int inc, const FIXP_DBL *RESTRICT coeff,
193                            const int order, FIXP_DBL *RESTRICT state);
194 
195 /**
196  * \brief
197  */
198 INT CLpc_ParcorToLpc(const FIXP_LPC_TNS reflCoeff[], FIXP_LPC_TNS LpcCoeff[],
199                      INT numOfCoeff, FIXP_DBL workBuffer[]);
200 INT CLpc_ParcorToLpc(const FIXP_LPC reflCoeff[], FIXP_LPC LpcCoeff[],
201                      const int numOfCoeff, FIXP_DBL workBuffer[]);
202 
203 /**
204  * \brief Calculate ParCor (Partial autoCorrelation, reflection) coefficients
205  * from autocorrelation coefficients using the Schur algorithm (instead of
206  * Levinson Durbin).
207  * \param acorr order+1 autocorrelation coefficients
208  * \param reflCoeff output reflection /ParCor coefficients. The first
209  * coefficient which is always 1.0 is ommitted.
210  * \param order number of acorr / reflCoeff coefficients.
211  * \param pPredictionGain_m prediction gain mantissa
212  * \param pPredictionGain_e prediction gain exponent
213  */
214 void CLpc_AutoToParcor(FIXP_DBL acorr[], const int acorr_e,
215                        FIXP_LPC reflCoeff[], const int order,
216                        FIXP_DBL *pPredictionGain_m, INT *pPredictionGain_e);
217 
218 #endif /* FDK_LPC_H */
219