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  • /*
     * AC-3 encoder & E-AC-3 encoder common header
     * Copyright (c) 2000 Fabrice Bellard
     * Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles@gmail.com>
     *
     * 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 2.1 of the License, or (at your option) any later version.
     *
     * 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 Libav; if not, write to the Free Software
     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
     */
    
    /**
     * @file
     * AC-3 encoder & E-AC-3 encoder common header
     */
    
    #ifndef AVCODEC_AC3ENC_H
    #define AVCODEC_AC3ENC_H
    
    #include <stdint.h>
    #include "ac3.h"
    #include "ac3dsp.h"
    #include "avcodec.h"
    #include "dsputil.h"
    #include "put_bits.h"
    #include "fft.h"
    
    #ifndef CONFIG_AC3ENC_FLOAT
    #define CONFIG_AC3ENC_FLOAT 0
    #endif
    
    
    #define OFFSET(param) offsetof(AC3EncodeContext, options.param)
    #define AC3ENC_PARAM (AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM)
    
    #define AC3ENC_TYPE_AC3_FIXED   0
    #define AC3ENC_TYPE_AC3         1
    #define AC3ENC_TYPE_EAC3        2
    
    
    #define AC3_NAME(x) ff_ac3_float_ ## x
    
    #define MAC_COEF(d,a,b) ((d)+=(a)*(b))
    
    #define COEF_MIN (-16777215.0/16777216.0)
    #define COEF_MAX ( 16777215.0/16777216.0)
    
    typedef float SampleType;
    typedef float CoefType;
    typedef float CoefSumType;
    #else
    
    #define AC3_NAME(x) ff_ac3_fixed_ ## x
    
    #define MAC_COEF(d,a,b) MAC64(d,a,b)
    
    #define COEF_MIN -16777215
    #define COEF_MAX  16777215
    
    typedef int16_t SampleType;
    typedef int32_t CoefType;
    typedef int64_t CoefSumType;
    #endif
    
    
    /**
     * Encoding Options used by AVOption.
     */
    typedef struct AC3EncOptions {
        /* AC-3 metadata options*/
        int dialogue_level;
        int bitstream_mode;
        float center_mix_level;
        float surround_mix_level;
        int dolby_surround_mode;
        int audio_production_info;
        int mixing_level;
        int room_type;
        int copyright;
        int original;
        int extended_bsi_1;
        int preferred_stereo_downmix;
        float ltrt_center_mix_level;
        float ltrt_surround_mix_level;
        float loro_center_mix_level;
        float loro_surround_mix_level;
        int extended_bsi_2;
        int dolby_surround_ex_mode;
        int dolby_headphone_mode;
        int ad_converter_type;
    
        int eac3_mixing_metadata;
        int eac3_info_metadata;
    
    
        /* other encoding options */
        int allow_per_frame_metadata;
        int stereo_rematrixing;
        int channel_coupling;
        int cpl_start;
    } AC3EncOptions;
    
    /**
     * Data for a single audio block.
     */
    typedef struct AC3Block {
        CoefType **mdct_coef;                       ///< MDCT coefficients
        int32_t  **fixed_coef;                      ///< fixed-point MDCT coefficients
        uint8_t  **exp;                             ///< original exponents
        uint8_t  **grouped_exp;                     ///< grouped exponents
        int16_t  **psd;                             ///< psd per frequency bin
        int16_t  **band_psd;                        ///< psd per critical band
        int16_t  **mask;                            ///< masking curve
        uint16_t **qmant;                           ///< quantized mantissas
        uint8_t  **cpl_coord_exp;                   ///< coupling coord exponents           (cplcoexp)
        uint8_t  **cpl_coord_mant;                  ///< coupling coord mantissas           (cplcomant)
        uint8_t  coeff_shift[AC3_MAX_CHANNELS];     ///< fixed-point coefficient shift values
        uint8_t  new_rematrixing_strategy;          ///< send new rematrixing flags in this block
        int      num_rematrixing_bands;             ///< number of rematrixing bands
        uint8_t  rematrixing_flags[4];              ///< rematrixing flags
        int      new_cpl_strategy;                  ///< send new coupling strategy
        int      cpl_in_use;                        ///< coupling in use for this block     (cplinu)
        uint8_t  channel_in_cpl[AC3_MAX_CHANNELS];  ///< channel in coupling                (chincpl)
        int      num_cpl_channels;                  ///< number of channels in coupling
    
        uint8_t  new_cpl_coords[AC3_MAX_CHANNELS];  ///< send new coupling coordinates      (cplcoe)
    
        uint8_t  cpl_master_exp[AC3_MAX_CHANNELS];  ///< coupling coord master exponents    (mstrcplco)
        int      new_snr_offsets;                   ///< send new SNR offsets
        int      new_cpl_leak;                      ///< send new coupling leak info
        int      end_freq[AC3_MAX_CHANNELS];        ///< end frequency bin                  (endmant)
    } AC3Block;
    
    /**
     * AC-3 encoder private context.
     */
    typedef struct AC3EncodeContext {
        AVClass *av_class;                      ///< AVClass used for AVOption
        AC3EncOptions options;                  ///< encoding options
    
        AVCodecContext *avctx;                  ///< parent AVCodecContext
    
        PutBitContext pb;                       ///< bitstream writer context
        DSPContext dsp;
        AC3DSPContext ac3dsp;                   ///< AC-3 optimized functions
    
        FFTContext mdct;                        ///< FFT context for MDCT calculation
        const SampleType *mdct_window;          ///< MDCT window function array
    
    
        AC3Block blocks[AC3_MAX_BLOCKS];        ///< per-block info
    
    
        int fixed_point;                        ///< indicates if fixed-point encoder is being used
    
        int eac3;                               ///< indicates if this is E-AC-3 vs. AC-3
        int bitstream_id;                       ///< bitstream id                           (bsid)
        int bitstream_mode;                     ///< bitstream mode                         (bsmod)
    
        int bit_rate;                           ///< target bit rate, in bits-per-second
        int sample_rate;                        ///< sampling frequency, in Hz
    
    
        int num_blks_code;                      ///< number of blocks code                  (numblkscod)
        int num_blocks;                         ///< number of blocks per frame
    
        int frame_size_min;                     ///< minimum frame size in case rounding is necessary
        int frame_size;                         ///< current frame size in bytes
        int frame_size_code;                    ///< frame size code                        (frmsizecod)
        uint16_t crc_inv[2];
        int64_t bits_written;                   ///< bit count    (used to avg. bitrate)
        int64_t samples_written;                ///< sample count (used to avg. bitrate)
    
        int fbw_channels;                       ///< number of full-bandwidth channels      (nfchans)
        int channels;                           ///< total number of channels               (nchans)
        int lfe_on;                             ///< indicates if there is an LFE channel   (lfeon)
        int lfe_channel;                        ///< channel index of the LFE channel
        int has_center;                         ///< indicates if there is a center channel
        int has_surround;                       ///< indicates if there are one or more surround channels
        int channel_mode;                       ///< channel mode                           (acmod)
        const uint8_t *channel_map;             ///< channel map used to reorder channels
    
        int center_mix_level;                   ///< center mix level code
        int surround_mix_level;                 ///< surround mix level code
        int ltrt_center_mix_level;              ///< Lt/Rt center mix level code
        int ltrt_surround_mix_level;            ///< Lt/Rt surround mix level code
        int loro_center_mix_level;              ///< Lo/Ro center mix level code
        int loro_surround_mix_level;            ///< Lo/Ro surround mix level code
    
        int cutoff;                             ///< user-specified cutoff frequency, in Hz
        int bandwidth_code;                     ///< bandwidth code (0 to 60)               (chbwcod)
        int start_freq[AC3_MAX_CHANNELS];       ///< start frequency bin                    (strtmant)
        int cpl_end_freq;                       ///< coupling channel end frequency bin
    
        int cpl_on;                             ///< coupling turned on for this frame
        int cpl_enabled;                        ///< coupling enabled for all frames
        int num_cpl_subbands;                   ///< number of coupling subbands            (ncplsubnd)
        int num_cpl_bands;                      ///< number of coupling bands               (ncplbnd)
        uint8_t cpl_band_sizes[AC3_MAX_CPL_BANDS];  ///< number of coeffs in each coupling band
    
        int rematrixing_enabled;                ///< stereo rematrixing enabled
    
        /* bitrate allocation control */
        int slow_gain_code;                     ///< slow gain code                         (sgaincod)
        int slow_decay_code;                    ///< slow decay code                        (sdcycod)
        int fast_decay_code;                    ///< fast decay code                        (fdcycod)
        int db_per_bit_code;                    ///< dB/bit code                            (dbpbcod)
        int floor_code;                         ///< floor code                             (floorcod)
        AC3BitAllocParameters bit_alloc;        ///< bit allocation parameters
        int coarse_snr_offset;                  ///< coarse SNR offsets                     (csnroffst)
        int fast_gain_code[AC3_MAX_CHANNELS];   ///< fast gain codes (signal-to-mask ratio) (fgaincod)
        int fine_snr_offset[AC3_MAX_CHANNELS];  ///< fine SNR offsets                       (fsnroffst)
        int frame_bits_fixed;                   ///< number of non-coefficient bits for fixed parameters
        int frame_bits;                         ///< all frame bits except exponents and mantissas
        int exponent_bits;                      ///< number of bits used for exponents
    
    
        SampleType **planar_samples;
        uint8_t *bap_buffer;
        uint8_t *bap1_buffer;
        CoefType *mdct_coef_buffer;
        int32_t *fixed_coef_buffer;
        uint8_t *exp_buffer;
        uint8_t *grouped_exp_buffer;
        int16_t *psd_buffer;
        int16_t *band_psd_buffer;
        int16_t *mask_buffer;
    
        uint8_t *cpl_coord_exp_buffer;
        uint8_t *cpl_coord_mant_buffer;
    
        uint8_t exp_strategy[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS]; ///< exponent strategies
    
        uint8_t frame_exp_strategy[AC3_MAX_CHANNELS];           ///< frame exp strategy index
        int use_frame_exp_strategy;                             ///< indicates use of frame exp strategy
    
        uint8_t exp_ref_block[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS]; ///< reference blocks for EXP_REUSE
        uint8_t *ref_bap     [AC3_MAX_CHANNELS][AC3_MAX_BLOCKS]; ///< bit allocation pointers (bap)
        int ref_bap_set;                                         ///< indicates if ref_bap pointers have been set
    
    
        /* fixed vs. float function pointers */
    
        void (*mdct_end)(struct AC3EncodeContext *s);
        int  (*mdct_init)(struct AC3EncodeContext *s);
    
    
        /* fixed vs. float templated function pointers */
    
        int  (*allocate_sample_buffers)(struct AC3EncodeContext *s);
    
    
        /* AC-3 vs. E-AC-3 function pointers */
    
        void (*output_frame_header)(struct AC3EncodeContext *s);
    
    
    extern const int64_t ff_ac3_channel_layouts[19];
    
    int ff_ac3_encode_init(AVCodecContext *avctx);
    
    int ff_ac3_encode_close(AVCodecContext *avctx);
    
    
    int ff_ac3_validate_metadata(AC3EncodeContext *s);
    
    
    void ff_ac3_adjust_frame_size(AC3EncodeContext *s);
    
    void ff_ac3_compute_coupling_strategy(AC3EncodeContext *s);
    
    void ff_ac3_apply_rematrixing(AC3EncodeContext *s);
    
    void ff_ac3_process_exponents(AC3EncodeContext *s);
    
    int ff_ac3_compute_bit_allocation(AC3EncodeContext *s);
    
    
    void ff_ac3_group_exponents(AC3EncodeContext *s);
    
    
    void ff_ac3_quantize_mantissas(AC3EncodeContext *s);
    
    void ff_ac3_output_frame(AC3EncodeContext *s, unsigned char *frame);
    
    
    
    /* prototypes for functions in ac3enc_fixed.c and ac3enc_float.c */
    
    
    void ff_ac3_fixed_mdct_end(AC3EncodeContext *s);
    void ff_ac3_float_mdct_end(AC3EncodeContext *s);
    
    int ff_ac3_fixed_mdct_init(AC3EncodeContext *s);
    int ff_ac3_float_mdct_init(AC3EncodeContext *s);
    
    
    
    /* prototypes for functions in ac3enc_template.c */
    
    
    int ff_ac3_fixed_allocate_sample_buffers(AC3EncodeContext *s);
    int ff_ac3_float_allocate_sample_buffers(AC3EncodeContext *s);
    
    
    int ff_ac3_fixed_encode_frame(AVCodecContext *avctx, unsigned char *frame,
                                  int buf_size, void *data);
    int ff_ac3_float_encode_frame(AVCodecContext *avctx, unsigned char *frame,
                                  int buf_size, void *data);
    
    #endif /* AVCODEC_AC3ENC_H */