/* * 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 #define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */ #define EAC3_MAX_CHANNELS 16 /**< maximum number of channels in EAC3 */ #define AC3_MAX_CHANNELS 7 /**< maximum number of channels, including coupling channel */ #define CPL_CH 0 /**< coupling channel index */ #define AC3_MAX_COEFS 256 #define AC3_BLOCK_SIZE 256 #define AC3_MAX_BLOCKS 6 #define AC3_FRAME_SIZE (AC3_MAX_BLOCKS * 256) #define AC3_WINDOW_SIZE (AC3_BLOCK_SIZE * 2) #define AC3_CRITICAL_BANDS 50 #define AC3_MAX_CPL_BANDS 18 #include "libavutil/opt.h" #include "avcodec.h" #include "ac3tab.h" /* exponent encoding strategy */ #define EXP_REUSE 0 #define EXP_NEW 1 #define EXP_D15 1 #define EXP_D25 2 #define EXP_D45 3 #ifndef USE_FIXED #define USE_FIXED 0 #endif #if USE_FIXED #define FFT_FLOAT 0 #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 */ #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 /** Delta bit allocation strategy */ typedef enum { DBA_REUSE = 0, DBA_NEW, DBA_NONE, DBA_RESERVED } AC3DeltaStrategy; /** Channel mode (audio coding mode) */ typedef enum { AC3_CHMODE_DUALMONO = 0, AC3_CHMODE_MONO, AC3_CHMODE_STEREO, AC3_CHMODE_3F, AC3_CHMODE_2F1R, AC3_CHMODE_3F1R, AC3_CHMODE_2F2R, AC3_CHMODE_3F2R } AC3ChannelMode; /** Dolby Surround mode */ typedef enum AC3DolbySurroundMode { AC3_DSURMOD_NOTINDICATED = 0, AC3_DSURMOD_OFF, AC3_DSURMOD_ON, AC3_DSURMOD_RESERVED } AC3DolbySurroundMode; /** Dolby Surround EX mode */ typedef enum AC3DolbySurroundEXMode { AC3_DSUREXMOD_NOTINDICATED = 0, AC3_DSUREXMOD_OFF, AC3_DSUREXMOD_ON, AC3_DSUREXMOD_PLIIZ } AC3DolbySurroundEXMode; /** Dolby Headphone mode */ typedef enum AC3DolbyHeadphoneMode { AC3_DHEADPHONMOD_NOTINDICATED = 0, AC3_DHEADPHONMOD_OFF, AC3_DHEADPHONMOD_ON, AC3_DHEADPHONMOD_RESERVED } AC3DolbyHeadphoneMode; /** Preferred Stereo Downmix mode */ typedef enum AC3PreferredStereoDownmixMode { AC3_DMIXMOD_NOTINDICATED = 0, AC3_DMIXMOD_LTRT, AC3_DMIXMOD_LORO, AC3_DMIXMOD_DPLII // reserved value in A/52, but used by encoders to indicate DPL2 } AC3PreferredStereoDownmixMode; 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; /** * @struct AC3HeaderInfo * Coded AC-3 header values up to the lfeon element, plus derived values. */ typedef struct AC3HeaderInfo { /** @name Coded elements * @{ */ uint16_t sync_word; uint16_t crc1; uint8_t sr_code; uint8_t bitstream_id; uint8_t bitstream_mode; uint8_t channel_mode; uint8_t lfe_on; uint8_t frame_type; int substreamid; ///< substream identification int center_mix_level; ///< Center mix level index int surround_mix_level; ///< Surround mix level index uint16_t channel_map; int num_blocks; ///< number of audio blocks int dolby_surround_mode; /** @} */ /** @name Derived values * @{ */ uint8_t sr_shift; uint16_t sample_rate; uint32_t bit_rate; uint8_t channels; uint16_t frame_size; uint64_t channel_layout; /** @} */ } AC3HeaderInfo; typedef enum { EAC3_FRAME_TYPE_INDEPENDENT = 0, EAC3_FRAME_TYPE_DEPENDENT, EAC3_FRAME_TYPE_AC3_CONVERT, EAC3_FRAME_TYPE_RESERVED } EAC3FrameType; void ff_ac3_common_init(void); /** * 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 */