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https://github.com/FFmpeg/FFmpeg.git
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104abea646
Move AC3HeaderInfo into ac3_parser_internal.h and the rest into a new header ac3defs.h. This also breaks an include cycle of ac3.h and ac3tab.h (the latter now only needs ac3defs.h). Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
148 lines
5.5 KiB
C
148 lines
5.5 KiB
C
/*
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* Common code between the AC-3 encoder and decoder
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* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Common code between the AC-3 encoder and decoder.
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*/
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#ifndef AVCODEC_AC3_H
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#define AVCODEC_AC3_H
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#include <math.h>
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#include <stdint.h>
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#include "ac3tab.h"
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#ifndef USE_FIXED
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#define USE_FIXED 0
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#endif
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#if USE_FIXED
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#define FFT_FLOAT 0
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#define FIXR(a) ((int)((a) * 0 + 0.5))
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#define FIXR12(a) ((int)((a) * 4096 + 0.5))
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#define FIXR15(a) ((int)((a) * 32768 + 0.5))
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#define ROUND15(x) ((x) + 16384) >> 15
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#define AC3_RENAME(x) x ## _fixed
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#define AC3_NORM(norm) (1<<24)/(norm)
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#define AC3_MUL(a,b) ((((int64_t) (a)) * (b))>>12)
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#define AC3_RANGE(x) ((x)|(((x)&128)<<1))
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#define AC3_HEAVY_RANGE(x) ((x)<<1)
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#define AC3_DYNAMIC_RANGE(x) (x)
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#define AC3_SPX_BLEND(x) (x)
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#define AC3_DYNAMIC_RANGE1 0
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typedef int INTFLOAT;
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typedef int16_t SHORTFLOAT;
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#else /* USE_FIXED */
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#include "libavutil/libm.h"
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#define FIXR(x) ((float)(x))
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#define FIXR12(x) ((float)(x))
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#define FIXR15(x) ((float)(x))
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#define ROUND15(x) (x)
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#define AC3_RENAME(x) x
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#define AC3_NORM(norm) (1.0f/(norm))
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#define AC3_MUL(a,b) ((a) * (b))
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#define AC3_RANGE(x) (dynamic_range_tab[(x)])
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#define AC3_HEAVY_RANGE(x) (ff_ac3_heavy_dynamic_range_tab[(x)])
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#define AC3_DYNAMIC_RANGE(x) (powf(x, s->drc_scale))
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#define AC3_SPX_BLEND(x) (x)* (1.0f/32)
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#define AC3_DYNAMIC_RANGE1 1.0f
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typedef float INTFLOAT;
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typedef float SHORTFLOAT;
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#endif /* USE_FIXED */
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#define AC3_LEVEL(x) ROUND15((x) * FIXR15(M_SQRT1_2))
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/* pre-defined gain values */
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#define LEVEL_PLUS_3DB M_SQRT2
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#define LEVEL_PLUS_1POINT5DB 1.1892071150027209
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#define LEVEL_MINUS_1POINT5DB 0.8408964152537145
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#define LEVEL_MINUS_3DB M_SQRT1_2
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#define LEVEL_MINUS_4POINT5DB 0.5946035575013605
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#define LEVEL_MINUS_6DB 0.5000000000000000
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#define LEVEL_MINUS_9DB 0.3535533905932738
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#define LEVEL_ZERO 0.0000000000000000
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#define LEVEL_ONE 1.0000000000000000
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typedef struct AC3BitAllocParameters {
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int sr_code;
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int sr_shift;
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int slow_gain, slow_decay, fast_decay, db_per_bit, floor;
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int cpl_fast_leak, cpl_slow_leak;
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} AC3BitAllocParameters;
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/**
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* Calculate the log power-spectral density of the input signal.
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* This gives a rough estimate of signal power in the frequency domain by using
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* the spectral envelope (exponents). The psd is also separately grouped
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* into critical bands for use in the calculating the masking curve.
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* 128 units in psd = -6 dB. The dbknee parameter in AC3BitAllocParameters
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* determines the reference level.
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*
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* @param[in] exp frequency coefficient exponents
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* @param[in] start starting bin location
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* @param[in] end ending bin location
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* @param[out] psd signal power for each frequency bin
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* @param[out] band_psd signal power for each critical band
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*/
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void ff_ac3_bit_alloc_calc_psd(int8_t *exp, int start, int end, int16_t *psd,
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int16_t *band_psd);
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/**
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* Calculate the masking curve.
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* First, the excitation is calculated using parameters in s and the signal
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* power in each critical band. The excitation is compared with a predefined
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* hearing threshold table to produce the masking curve. If delta bit
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* allocation information is provided, it is used for adjusting the masking
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* curve, usually to give a closer match to a better psychoacoustic model.
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*
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* @param[in] s adjustable bit allocation parameters
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* @param[in] band_psd signal power for each critical band
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* @param[in] start starting bin location
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* @param[in] end ending bin location
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* @param[in] fast_gain fast gain (estimated signal-to-mask ratio)
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* @param[in] is_lfe whether or not the channel being processed is the LFE
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* @param[in] dba_mode delta bit allocation mode (none, reuse, or new)
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* @param[in] dba_nsegs number of delta segments
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* @param[in] dba_offsets location offsets for each segment
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* @param[in] dba_lengths length of each segment
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* @param[in] dba_values delta bit allocation for each segment
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* @param[out] mask calculated masking curve
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* @return returns 0 for success, non-zero for error
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*/
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int ff_ac3_bit_alloc_calc_mask(AC3BitAllocParameters *s, int16_t *band_psd,
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int start, int end, int fast_gain, int is_lfe,
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int dba_mode, int dba_nsegs, uint8_t *dba_offsets,
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uint8_t *dba_lengths, uint8_t *dba_values,
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int16_t *mask);
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#endif /* AVCODEC_AC3_H */
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