fdk-aac/libArithCoding/include/ac_arith_coder.h

/* -----------------------------------------------------------------------------
Software License for The Fraunhofer FDK AAC Codec Library for Android

© Copyright  1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten
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 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
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already be covered under those patent licenses when it is used for those
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Commercially-licensed AAC software libraries, including floating-point versions
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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
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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
----------------------------------------------------------------------------- */

/************************** Arithmetic coder library ***************************

   Author(s):   Oliver Weiss

   Description: Interface for Spectral Noiseless Coding Scheme based on an
                Arithmetic Coder in Conjunction with an Adaptive Context

*******************************************************************************/

#ifndef AC_ARITH_CODER_H
#define AC_ARITH_CODER_H

#include "common_fix.h"
#include "FDK_bitstream.h"

#include "FDK_audio.h"

typedef enum { ARITH_CODER_OK = 0, ARITH_CODER_ERROR = 5 } ARITH_CODING_ERROR;

typedef struct {
  SHORT m_numberLinesPrev;
  UCHAR c_prev[(1024 / 2) + 4]; /* 2-tuple context of previous frame, 4 bit */
} CArcoData;

/* prototypes */

CArcoData *CArco_Create(void);

void CArco_Destroy(CArcoData *pArcoData);

/**
 * \brief decode a spectral data element by using an adaptive context dependent
 * arithmetic coding scheme
 * \param hBs bit stream handle
 * \param spectrum pointer to quantized data output.
 * \param lg number of quantized spectral coefficients (output by the arithmetic
 * decoder).
 * \param lg_max max number of quantized spectral coefficients.
 * \param arith_reset_flag flag which indicates if the spectral noiseless
 * context must be reset
 * \return void
 */
ARITH_CODING_ERROR CArco_DecodeArithData(CArcoData *pArcoData,
                                         HANDLE_FDK_BITSTREAM hBs,
                                         FIXP_DBL *RESTRICT spectrum, int lg,
                                         int lg_max, int arith_reset_flag);

#endif /* AC_ARITH_CODER_H */