diff options
Diffstat (limited to 'fdk-aac/libFDK/include/FDK_lpc.h')
| -rw-r--r-- | fdk-aac/libFDK/include/FDK_lpc.h | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/fdk-aac/libFDK/include/FDK_lpc.h b/fdk-aac/libFDK/include/FDK_lpc.h new file mode 100644 index 0000000..851dd1f --- /dev/null +++ b/fdk-aac/libFDK/include/FDK_lpc.h @@ -0,0 +1,218 @@ +/* ----------------------------------------------------------------------------- +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 +your modifications thereto in binary form. You must make available free of +charge copies of the complete source code of the FDK AAC Codec and your +modifications thereto to recipients of copies in binary form. + +The name of Fraunhofer may not be used to endorse or promote products derived +from this library without prior written permission. + +You may not charge copyright license fees for anyone to use, copy or distribute +the FDK AAC Codec software or your modifications thereto. + +Your modified versions of the FDK AAC Codec must carry prominent notices stating +that you changed the software and the date of any change. For modified versions +of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android" +must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK +AAC Codec Library for Android." + +3. NO PATENT LICENSE + +NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without +limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE. +Fraunhofer provides no warranty of patent non-infringement with respect to this +software. + +You may use this FDK AAC Codec software or modifications thereto only for +purposes that are authorized by appropriate patent licenses. + +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, +including but not limited to the implied warranties of merchantability and +fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR +CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, +or consequential damages, including but not limited to procurement of substitute +goods or services; loss of use, data, or profits, or business interruption, +however caused and on any theory of liability, whether in contract, strict +liability, or tort (including negligence), arising in any way out of the use of +this software, even if advised of the possibility of such damage. + +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 +amm-info@iis.fraunhofer.de +----------------------------------------------------------------------------- */ + +/******************* Library for basic calculation routines ******************** + + Author(s): Manuel Jander + + Description: LPC related functions + +*******************************************************************************/ + +#ifndef FDK_LPC_H +#define FDK_LPC_H + +#include "common_fix.h" + +#define LPC_MAX_ORDER 24 + +/* + * Experimental solution for lattice filter substitution. + * LPC_SYNTHESIS_IIR macro must be activated in aacdec_tns.cpp. + * When LPC_SYNTHESIS_IIR enabled, there will be a substitution of the default + * lpc synthesis lattice filter by an IIR synthesis filter (with a conversionof + * the filter coefs). LPC_TNS related macros are intended to implement the data + * types used by the CLpc_Synthesis variant which is used for this solution. + * */ + +/* #define LPC_TNS_LOWER_PRECISION */ + +typedef FIXP_DBL FIXP_LPC_TNS; +#define FX_DBL2FX_LPC_TNS(x) (x) +#define FX_DBL2FXCONST_LPC_TNS(x) (x) +#define FX_LPC_TNS2FX_DBL(x) (x) +#define FL2FXCONST_LPC_TNS(val) FL2FXCONST_DBL(val) +#define MAXVAL_LPC_TNS MAXVAL_DBL + +typedef FIXP_SGL FIXP_LPC; +#define FX_DBL2FX_LPC(x) FX_DBL2FX_SGL((FIXP_DBL)(x)) +#define FX_DBL2FXCONST_LPC(x) FX_DBL2FXCONST_SGL(x) +#define FX_LPC2FX_DBL(x) FX_SGL2FX_DBL(x) +#define FL2FXCONST_LPC(val) FL2FXCONST_SGL(val) +#define MAXVAL_LPC MAXVAL_SGL + +/** + * \brief Obtain residual signal through LPC analysis. + * \param signal pointer to buffer holding signal to be analysed. Residual is + * returned there (in place) + * \param signal_size the size of the input data in pData + * \param lpcCoeff_m the LPC filter coefficient mantissas + * \param lpcCoeff_e the LPC filter coefficient exponent + * \param order the LPC filter order (size of coeff) + * \param filtState Pointer to state buffer of size order + * \param filtStateIndex pointer to state index storage + */ +void CLpc_Analysis(FIXP_DBL signal[], const int signal_size, + const FIXP_LPC lpcCoeff_m[], const int lpcCoeff_e, + const int order, FIXP_DBL *filtState, int *filtStateIndex); + +/** + * \brief Synthesize signal fom residual through LPC synthesis, using LP + * coefficients. + * \param signal pointer to buffer holding the residual signal. The synthesis is + * returned there (in place) + * \param signal_size the size of the input data in pData + * \param inc buffer traversal increment for signal + * \param coeff the LPC filter coefficients + * \param coeff_e exponent of coeff + * \param order the LPC filter order (size of coeff) + * \param state state buffer of size LPC_MAX_ORDER + * \param pStateIndex pointer to state index storage + */ +void CLpc_Synthesis(FIXP_DBL *signal, const int signal_size, const int signal_e, + const int inc, const FIXP_LPC_TNS *lpcCoeff_m, + const int lpcCoeff_e, const int order, FIXP_DBL *state, + int *pStateIndex); +void CLpc_Synthesis(FIXP_DBL *signal, const int signal_size, const int signal_e, + const int inc, const FIXP_LPC coeff[], const int coeff_e, + const int order, FIXP_DBL *filtState, int *pStateIndex); + +/** + * \brief Synthesize signal fom residual through LPC synthesis, using ParCor + * coefficients. The algorithm assumes a filter gain of max 1.0. If the filter + * gain is higher, this must be accounted into the values of signal_e + * and/or signal_e_out to avoid overflows. + * \param signal pointer to buffer holding the residual signal. The synthesis is + * returned there (in place) + * \param signal_size the size of the input data in pData + * \param inc buffer traversal increment for signal + * \param coeff the LPC filter coefficients + * \param coeff_e exponent of coeff + * \param order the LPC filter order (size of coeff) + * \param state state buffer of size LPC_MAX_ORDER + */ +void CLpc_SynthesisLattice(FIXP_DBL *signal, const int signal_size, + const int signal_e, const int signal_e_out, + const int inc, const FIXP_SGL *coeff, + const int order, FIXP_DBL *state); + +void CLpc_SynthesisLattice(FIXP_DBL *RESTRICT signal, const int signal_size, + const int signal_e, const int signal_e_out, + const int inc, const FIXP_DBL *RESTRICT coeff, + const int order, FIXP_DBL *RESTRICT state); + +/** + * \brief + */ +INT CLpc_ParcorToLpc(const FIXP_LPC_TNS reflCoeff[], FIXP_LPC_TNS LpcCoeff[], + INT numOfCoeff, FIXP_DBL workBuffer[]); +INT CLpc_ParcorToLpc(const FIXP_LPC reflCoeff[], FIXP_LPC LpcCoeff[], + const int numOfCoeff, FIXP_DBL workBuffer[]); + +/** + * \brief Calculate ParCor (Partial autoCorrelation, reflection) coefficients + * from autocorrelation coefficients using the Schur algorithm (instead of + * Levinson Durbin). + * \param acorr order+1 autocorrelation coefficients + * \param reflCoeff output reflection /ParCor coefficients. The first + * coefficient which is always 1.0 is ommitted. + * \param order number of acorr / reflCoeff coefficients. + * \param pPredictionGain_m prediction gain mantissa + * \param pPredictionGain_e prediction gain exponent + */ +void CLpc_AutoToParcor(FIXP_DBL acorr[], const int acorr_e, + FIXP_LPC reflCoeff[], const int order, + FIXP_DBL *pPredictionGain_m, INT *pPredictionGain_e); + +#endif /* FDK_LPC_H */ |