xref: /aosp_15_r20/external/aac/libAACdec/src/usacdec_const.h (revision e54365361535b070c2db7374cec45c159c7d0e7a)

/* -----------------------------------------------------------------------------
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
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that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding
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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
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specifications.

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Commercially-licensed AAC software libraries, including floating-point versions
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information and documentation.

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Redistribution and use in source and binary forms, with or without modification,
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Attention: Audio and Multimedia Departments - FDK AAC LL
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www.iis.fraunhofer.de/amm
[email protected]
----------------------------------------------------------------------------- */

/**************************** AAC decoder library ******************************

   Author(s):   Manuel Jander

   Description: USAC related constants

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

#ifndef USACDEC_CONST_H
#define USACDEC_CONST_H

/* scale factors */
#define SF_CODE 6       /* exponent of code[], fixed codebook vector */
#define SF_GAIN_C 16    /* exponent of gain code and smoothed gain code */
#define SF_EXC 16       /* exponent of exc[] and exc2[], excitation buffer */
#define SF_GAIN_P 1     /* exponent of gain_pit */
#define SF_PFAC 0       /* exponent of period/voicing factor */
#define SF_SYNTH SF_EXC /* exponent of synthesis buffer */
#define SF_A_COEFFS 3   /* exponent of LP domain synthesis filter coefficient */
#define SF_STAB 1       /* exponent of stability factor */

/* definitions which are independent of coreCoderFrameLength */
#define M_LP_FILTER_ORDER 16 /* LP filter order */
#define LP_FILTER_SCALE 4    /* LP filter scale */

#define PIT_MIN_12k8 34    /* Minimum pitch lag with resolution 1/4 */
#define PIT_MAX_12k8 231   /* Maximum pitch lag for fs=12.8kHz */
#define FSCALE_DENOM 12800 /* Frequency scale denominator */
#define FAC_FSCALE_MIN \
  6000 /* Minimum allowed frequency scale for acelp decoder */

#if !defined(LPD_MAX_CORE_SR)
#define LPD_MAX_CORE_SR 24000 /* Default value from ref soft */
#endif
#define FAC_FSCALE_MAX \
  LPD_MAX_CORE_SR /* Maximum allowed frequency scale for acelp decoder */

/* Maximum pitch lag (= 411 for fs_max = 24000) */
#define PIT_MAX_TMP                                                            \
  (PIT_MAX_12k8 +                                                              \
   (6 *                                                                        \
    ((((FAC_FSCALE_MAX * PIT_MIN_12k8) + (FSCALE_DENOM / 2)) / FSCALE_DENOM) - \
     PIT_MIN_12k8)))
#if (PIT_MAX_TMP < \
     256) /* cannot be smaller because of tcx time domain concealment */
#define PIT_MAX_MAX 256
#else
#define PIT_MAX_MAX PIT_MAX_TMP
#endif

#define NB_DIV 4   /* number of division (20ms) per 80ms frame */
#define L_SUBFR 64 /* subframe size (5ms) */
#define BPF_SFD 1  /* bass postfilter delay (subframe) */
#define BPF_DELAY (BPF_SFD * L_SUBFR) /* bass postfilter delay (samples) */

#define L_FILT 12  /* Delay of up-sampling filter (bass post-filter) */
#define L_EXTRA 96 /* for bass post-filter */
#define L_INTERPOL \
  (16 + 1) /* Length of filter for interpolation (acelp decoder) */

/* definitions for coreCoderFrameLength = 1024 */
#define L_FRAME_PLUS_1024 1024 /* length of one 80ms superframe */
#define L_DIV_1024 \
  (L_FRAME_PLUS_1024 / NB_DIV) /* length of one acelp or tcx20 frame */
#define NB_SUBFR_1024 \
  (L_DIV_1024 / L_SUBFR) /* number of 5ms subframe per division */
#define NB_SUBFR_SUPERFR_1024 \
  (L_FRAME_PLUS_1024 / L_SUBFR) /* number of 5ms subframe per 80ms frame */
#define AAC_SFD_1024 (NB_SUBFR_SUPERFR_1024 / 2) /* AAC delay (subframe) */
#define AAC_DELAY_1024 (AAC_SFD_1024 * L_SUBFR)  /* AAC delay (samples) */
#define SYN_SFD_1024 (AAC_SFD_1024 - BPF_SFD) /* synthesis delay (subframe) */
#define SYN_DELAY_1024                                          \
  (SYN_SFD_1024 * L_SUBFR)         /* synthesis delay (samples) \
                                    */
#define LFAC_1024 (L_DIV_1024 / 2) /* FAC frame length */
#define LFAC_SHORT_1024 \
  (L_DIV_1024 / 4)        /* for transitions EIGHT_SHORT FD->LPD and vv. */
#define FDNS_NPTS_1024 64 /* FD noise shaping resolution (64=100Hz/point) */

/* definitions for coreCoderFrameLength = 768 */
#define L_FRAME_PLUS_768 768
#define L_DIV_768 \
  (L_FRAME_PLUS_768 / NB_DIV) /* length of one acelp or tcx20 frame */
#define NB_SUBFR_768 \
  (L_DIV_768 / L_SUBFR) /* number of 5ms subframe per division */
#define NB_SUBFR_SUPERFR_768 \
  (L_FRAME_PLUS_768 / L_SUBFR) /* number of 5ms subframe per 80ms frame */
#define AAC_SFD_768 (NB_SUBFR_SUPERFR_768 / 2) /* AAC delay (subframe) */
#define AAC_DELAY_768 (AAC_SFD_768 * L_SUBFR)  /* AAC delay (samples) */
#define SYN_SFD_768 (AAC_SFD_768 - BPF_SFD)    /* synthesis delay (subframe) */
#define SYN_DELAY_768 (SYN_SFD_768 * L_SUBFR)  /* synthesis delay (samples) */
#define LFAC_768 (L_DIV_768 / 2)               /* FAC frame length */
#define LFAC_SHORT_768 \
  (L_DIV_768 / 4) /* for transitions EIGHT_SHORT FD->LPD and vv. */

/* maximum (used for memory allocation) */
#define L_FRAME_PLUS L_FRAME_PLUS_1024
#define L_DIV L_DIV_1024
#define NB_SUBFR NB_SUBFR_1024
#define NB_SUBFR_SUPERFR NB_SUBFR_SUPERFR_1024
#define AAC_SFD AAC_SFD_1024
#define AAC_DELAY AAC_DELAY_1024
#define SYN_SFD SYN_SFD_1024
#define SYN_DELAY SYN_DELAY_1024
#define LFAC LFAC_1024
#define LFAC_SHORT LFAC_SHORT_1024
#define FDNS_NPTS FDNS_NPTS_1024

#endif /* USACDEC_CONST_H */