X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fac3.h;h=304c86c1812e608e6e9c4a5b52ae3cb6fcf55ba1;hb=0b8b3387a977dcdb6fb9e53bcc9966d34b2e4cec;hp=51583edfa99130da20550d24d8a696bd5e053316;hpb=0c1a9edad463bd6e22b30c19b700b099c7093fc1;p=ffmpeg diff --git a/libavcodec/ac3.h b/libavcodec/ac3.h index 51583edfa99..304c86c1812 100644 --- a/libavcodec/ac3.h +++ b/libavcodec/ac3.h @@ -1,27 +1,45 @@ /* - * Common code between AC3 encoder and decoder - * Copyright (c) 2000, 2001, 2002 Fabrice Bellard. + * Common code between the AC-3 encoder and decoder + * Copyright (c) 2000, 2001, 2002 Fabrice Bellard * - * This library is free software; you can redistribute it and/or + * This file is part of Libav. + * + * Libav 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 of the License, or (at your option) any later version. + * version 2.1 of the License, or (at your option) any later version. * - * This library is distributed in the hope that it will be useful, + * Libav 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 this library; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * License along with Libav; 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 AC3_MAX_CHANNELS 6 /* including LFE channel */ +#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 -#define NB_BLOCKS 6 /* number of PCM blocks inside an AC3 frame */ -#define AC3_FRAME_SIZE (NB_BLOCKS * 256) +#include "ac3tab.h" /* exponent encoding strategy */ #define EXP_REUSE 0 @@ -31,26 +49,131 @@ #define EXP_D25 2 #define EXP_D45 3 +/* pre-defined gain values */ +#define LEVEL_PLUS_3DB 1.4142135623730950 +#define LEVEL_PLUS_1POINT5DB 1.1892071150027209 +#define LEVEL_MINUS_1POINT5DB 0.8408964152537145 +#define LEVEL_MINUS_3DB 0.7071067811865476 +#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; + typedef struct AC3BitAllocParameters { - int fscod; /* frequency */ - int halfratecod; - int sgain, sdecay, fdecay, dbknee, floor; - int cplfleak, cplsleak; + 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; -extern const uint16_t ac3_freqs[3]; -extern const uint16_t ac3_bitratetab[19]; -extern const int16_t ac3_window[256]; -extern const uint8_t sdecaytab[4]; -extern const uint8_t fdecaytab[4]; -extern const uint16_t sgaintab[4]; -extern const uint16_t dbkneetab[4]; -extern const uint16_t floortab[8]; -extern const uint16_t fgaintab[8]; - -void ac3_common_init(void); -void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, uint8_t *bap, - int8_t *exp, int start, int end, - int snroffset, int fgain, int is_lfe, - int deltbae,int deltnseg, - uint8_t *deltoffst, uint8_t *deltlen, uint8_t *deltba); +/** + * @struct AC3HeaderInfo + * Coded AC-3 header values up to the lfeon element, plus derived values. + */ +typedef struct { + /** @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 + /** @} */ + + /** @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 */