X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fac3.h;h=9adad93db8e9c5aaf229c5ed9bb6a3dd572138c2;hb=f64e0a2f379c1297dc9b1744999e29ab84646261;hp=5ece9acf840568846e686c4ad04d90591a6db95d;hpb=72a6244b5d554d7fdfdeb04c174750c7a2c52f83;p=ffmpeg diff --git a/libavcodec/ac3.h b/libavcodec/ac3.h index 5ece9acf840..9adad93db8e 100644 --- a/libavcodec/ac3.h +++ b/libavcodec/ac3.h @@ -1,39 +1,45 @@ /* * Common code between the AC-3 encoder and decoder - * Copyright (c) 2000, 2001, 2002 Fabrice Bellard. + * Copyright (c) 2000, 2001, 2002 Fabrice Bellard * - * This file is part of FFmpeg. + * This file is part of Libav. * - * FFmpeg is free software; you can redistribute it and/or + * 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 2.1 of the License, or (at your option) any later version. * - * FFmpeg 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 FFmpeg; if not, write to the Free Software + * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** - * @file ac3.h + * @file * Common code between the AC-3 encoder and decoder. */ #ifndef AVCODEC_AC3_H #define AVCODEC_AC3_H -#include "ac3tab.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 AC-3 frame */ -#define AC3_FRAME_SIZE (NB_BLOCKS * 256) +#include "ac3tab.h" /* exponent encoding strategy */ #define EXP_REUSE 0 @@ -43,6 +49,17 @@ #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, @@ -75,13 +92,14 @@ typedef struct AC3BitAllocParameters { * Coded AC-3 header values up to the lfeon element, plus derived values. */ typedef struct { - /** @defgroup coded Coded elements + /** @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; @@ -92,7 +110,7 @@ typedef struct { int num_blocks; ///< number of audio blocks /** @} */ - /** @defgroup derived Derived values + /** @name Derived values * @{ */ uint8_t sr_shift; @@ -100,6 +118,7 @@ typedef struct { uint32_t bit_rate; uint8_t channels; uint16_t frame_size; + int64_t channel_layout; /** @} */ } AC3HeaderInfo; @@ -110,10 +129,10 @@ typedef enum { EAC3_FRAME_TYPE_RESERVED } EAC3FrameType; -void ac3_common_init(void); +void ff_ac3_common_init(void); /** - * Calculates the log power-spectral density of the input signal. + * 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. @@ -130,8 +149,8 @@ void ff_ac3_bit_alloc_calc_psd(int8_t *exp, int start, int end, int16_t *psd, int16_t *band_psd); /** - * Calculates the masking curve. - * First, the excitation is calculated using parameters in \p s and the signal + * 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 @@ -152,35 +171,9 @@ void ff_ac3_bit_alloc_calc_psd(int8_t *exp, int start, int end, int16_t *psd, * @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); - -/** - * Calculates bit allocation pointers. - * The SNR is the difference between the masking curve and the signal. AC-3 - * uses this value for each frequency bin to allocate bits. The \p snroffset - * parameter is a global adjustment to the SNR for all bins. - * - * @param[in] mask masking curve - * @param[in] psd signal power for each frequency bin - * @param[in] start starting bin location - * @param[in] end ending bin location - * @param[in] snr_offset SNR adjustment - * @param[in] floor noise floor - * @param[in] bap_tab look-up table for bit allocation pointers - * @param[out] bap bit allocation pointers - */ -void ff_ac3_bit_alloc_calc_bap(int16_t *mask, int16_t *psd, int start, int end, - int snr_offset, int floor, - const uint8_t *bap_tab, uint8_t *bap); - -void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, uint8_t *bap, - int8_t *exp, int start, int end, - int snr_offset, int fast_gain, int is_lfe, - int dba_mode, int dba_nsegs, - uint8_t *dba_offsets, uint8_t *dba_lengths, - uint8_t *dba_values); + 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 */