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/*
* Common code between the AC-3 encoder and decoder
* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Common code between the AC-3 encoder and decoder.
*/
#ifndef AVCODEC_AC3_H
#define AVCODEC_AC3_H
#include <math.h>
#include <stdint.h>
#include "ac3tab.h"
#ifndef USE_FIXED
#define USE_FIXED 0
#endif
#if USE_FIXED
#define FIXR(a) ((int)((a) * 0 + 0.5))
#define FIXR12(a) ((int)((a) * 4096 + 0.5))
#define FIXR15(a) ((int)((a) * 32768 + 0.5))
#define ROUND15(x) ((x) + 16384) >> 15
#define AC3_RENAME(x) x ## _fixed
#define AC3_NORM(norm) (1<<24)/(norm)
#define AC3_MUL(a,b) ((((int64_t) (a)) * (b))>>12)
#define AC3_RANGE(x) ((x)|(((x)&128)<<1))
#define AC3_HEAVY_RANGE(x) ((x)<<1)
#define AC3_DYNAMIC_RANGE(x) (x)
#define AC3_SPX_BLEND(x) (x)
#define AC3_DYNAMIC_RANGE1 0
typedef int INTFLOAT;
typedef int16_t SHORTFLOAT;
#else /* USE_FIXED */
#include "libavutil/libm.h"
#define FIXR(x) ((float)(x))
#define FIXR12(x) ((float)(x))
#define FIXR15(x) ((float)(x))
#define ROUND15(x) (x)
#define AC3_RENAME(x) x
#define AC3_NORM(norm) (1.0f/(norm))
#define AC3_MUL(a,b) ((a) * (b))
#define AC3_RANGE(x) (dynamic_range_tab[(x)])
#define AC3_HEAVY_RANGE(x) (ff_ac3_heavy_dynamic_range_tab[(x)])
#define AC3_DYNAMIC_RANGE(x) (powf(x, s->drc_scale))
#define AC3_SPX_BLEND(x) (x)* (1.0f/32)
#define AC3_DYNAMIC_RANGE1 1.0f
typedef float INTFLOAT;
typedef float SHORTFLOAT;
#endif /* USE_FIXED */
#define AC3_LEVEL(x) ROUND15((x) * FIXR15(M_SQRT1_2))
/* pre-defined gain values */
#define LEVEL_PLUS_3DB M_SQRT2
#define LEVEL_PLUS_1POINT5DB 1.1892071150027209
#define LEVEL_MINUS_1POINT5DB 0.8408964152537145
#define LEVEL_MINUS_3DB M_SQRT1_2
#define LEVEL_MINUS_4POINT5DB 0.5946035575013605
#define LEVEL_MINUS_6DB 0.5000000000000000
#define LEVEL_MINUS_9DB 0.3535533905932738
#define LEVEL_ZERO 0.0000000000000000
#define LEVEL_ONE 1.0000000000000000
typedef struct AC3BitAllocParameters {
int sr_code;
int sr_shift;
int slow_gain, slow_decay, fast_decay, db_per_bit, floor;
int cpl_fast_leak, cpl_slow_leak;
} AC3BitAllocParameters;
/**
* Calculate the log power-spectral density of the input signal.
* This gives a rough estimate of signal power in the frequency domain by using
* the spectral envelope (exponents). The psd is also separately grouped
* into critical bands for use in the calculating the masking curve.
* 128 units in psd = -6 dB. The dbknee parameter in AC3BitAllocParameters
* determines the reference level.
*
* @param[in] exp frequency coefficient exponents
* @param[in] start starting bin location
* @param[in] end ending bin location
* @param[out] psd signal power for each frequency bin
* @param[out] band_psd signal power for each critical band
*/
void ff_ac3_bit_alloc_calc_psd(int8_t *exp, int start, int end, int16_t *psd,
int16_t *band_psd);
/**
* Calculate the masking curve.
* First, the excitation is calculated using parameters in s and the signal
* power in each critical band. The excitation is compared with a predefined
* hearing threshold table to produce the masking curve. If delta bit
* allocation information is provided, it is used for adjusting the masking
* curve, usually to give a closer match to a better psychoacoustic model.
*
* @param[in] s adjustable bit allocation parameters
* @param[in] band_psd signal power for each critical band
* @param[in] start starting bin location
* @param[in] end ending bin location
* @param[in] fast_gain fast gain (estimated signal-to-mask ratio)
* @param[in] is_lfe whether or not the channel being processed is the LFE
* @param[in] dba_mode delta bit allocation mode (none, reuse, or new)
* @param[in] dba_nsegs number of delta segments
* @param[in] dba_offsets location offsets for each segment
* @param[in] dba_lengths length of each segment
* @param[in] dba_values delta bit allocation for each segment
* @param[out] mask calculated masking curve
* @return returns 0 for success, non-zero for error
*/
int ff_ac3_bit_alloc_calc_mask(AC3BitAllocParameters *s, int16_t *band_psd,
int start, int end, int fast_gain, int is_lfe,
int dba_mode, int dba_nsegs, uint8_t *dba_offsets,
uint8_t *dba_lengths, uint8_t *dba_values,
int16_t *mask);
#endif /* AVCODEC_AC3_H */
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