android / platform / external / aac / ce97e7d55e1f69683b5bc8f19cc8da8c85bc2cd4 / . / libFDK / include / FDK_lpc.h

/* ----------------------------------------------------------------------------- | |

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 */ |