xref: /aosp_15_r20/external/aac/libSBRdec/src/env_calc.h (revision e54365361535b070c2db7374cec45c159c7d0e7a)

/* -----------------------------------------------------------------------------
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
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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
with enhanced sound quality, are also available from Fraunhofer. Users are
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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
the FDK AAC Codec or your modifications thereto in source code form.

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Attention: Audio and Multimedia Departments - FDK AAC LL
Am Wolfsmantel 33
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www.iis.fraunhofer.de/amm
[email protected]
----------------------------------------------------------------------------- */

/**************************** SBR decoder library ******************************

   Author(s):

   Description:

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

/*!
  \file
  \brief  Envelope calculation prototypes
*/
#ifndef ENV_CALC_H
#define ENV_CALC_H

#include "sbrdecoder.h"
#include "env_extr.h" /* for HANDLE_SBR_HEADER_DATA */

typedef struct {
  FIXP_DBL filtBuffer[MAX_FREQ_COEFFS];      /*!< previous gains (required for
                                                smoothing) */
  FIXP_DBL filtBufferNoise[MAX_FREQ_COEFFS]; /*!< previous noise levels
                                                (required for smoothing) */
  SCHAR filtBuffer_e[MAX_FREQ_COEFFS];       /*!< Exponents of previous gains */
  SCHAR filtBufferNoise_e; /*!< Common exponent of previous noise levels */

  int startUp;     /*!< flag to signal initial conditions in buffers */
  int phaseIndex;  /*!< Index for randomPase array */
  int prevTranEnv; /*!< The transient envelope of the previous frame. */

  ULONG harmFlagsPrev[ADD_HARMONICS_FLAGS_SIZE];
  /*!< Words with 16 flags each indicating where a sine was added in the
   * previous frame.*/
  UCHAR harmIndex;     /*!< Current phase of synthetic sine */
  int sbrPatchingMode; /*!< Current patching mode           */

  FIXP_SGL prevSbrNoiseFloorLevel[MAX_NOISE_COEFFS];
  UCHAR prevNNfb;
  UCHAR prevNSfb[2];
  UCHAR prevLoSubband;
  UCHAR prevHiSubband;
  UCHAR prev_ov_highSubband;
  UCHAR *prevFreqBandTable[2];
  UCHAR prevFreqBandTableLo[MAX_FREQ_COEFFS / 2 + 1];
  UCHAR prevFreqBandTableHi[MAX_FREQ_COEFFS + 1];
  UCHAR prevFreqBandTableNoise[MAX_NOISE_COEFFS + 1];
  SCHAR sinusoidal_positionPrev;
  ULONG harmFlagsPrevActive[ADD_HARMONICS_FLAGS_SIZE];
} SBR_CALCULATE_ENVELOPE;

typedef SBR_CALCULATE_ENVELOPE *HANDLE_SBR_CALCULATE_ENVELOPE;

void calculateSbrEnvelope(
    QMF_SCALE_FACTOR *sbrScaleFactor,
    HANDLE_SBR_CALCULATE_ENVELOPE h_sbr_cal_env,
    HANDLE_SBR_HEADER_DATA hHeaderData, HANDLE_SBR_FRAME_DATA hFrameData,
    PVC_DYNAMIC_DATA *pPvcDynamicData, FIXP_DBL **analysBufferReal,
    FIXP_DBL *
        *analysBufferImag, /*!< Imag part of subband samples to be processed */
    const int useLP,
    FIXP_DBL *degreeAlias, /*!< Estimated aliasing for each QMF channel */
    const UINT flags, const int frameErrorFlag);

SBR_ERROR
createSbrEnvelopeCalc(HANDLE_SBR_CALCULATE_ENVELOPE hSbrCalculateEnvelope,
                      HANDLE_SBR_HEADER_DATA hHeaderData, const int chan,
                      const UINT flags);

int deleteSbrEnvelopeCalc(HANDLE_SBR_CALCULATE_ENVELOPE hSbrCalculateEnvelope);

void resetSbrEnvelopeCalc(HANDLE_SBR_CALCULATE_ENVELOPE hCalEnv);

SBR_ERROR
ResetLimiterBands(UCHAR *limiterBandTable, UCHAR *noLimiterBands,
                  UCHAR *freqBandTable, int noFreqBands,
                  const PATCH_PARAM *patchParam, int noPatches,
                  int limiterBands, UCHAR sbrPatchingMode,
                  int xOverQmf[MAX_NUM_PATCHES], int sbrRatio);

void rescaleSubbandSamples(FIXP_DBL **re, FIXP_DBL **im, int lowSubband,
                           int noSubbands, int start_pos, int next_pos,
                           int shift);

FIXP_DBL maxSubbandSample(FIXP_DBL **analysBufferReal_m,
                          FIXP_DBL **analysBufferImag_m, int lowSubband,
                          int highSubband, int start_pos, int stop_pos);

#endif  // ENV_CALC_H