h264.h

播放H264文件的播放器

    /**
     * Motion vector cache.
     */
    DECLARE_ALIGNED_8(int16_t, mv_cache[2][5*8][2]);
    DECLARE_ALIGNED_8(int8_t, ref_cache[2][5*8]);
#define LIST_NOT_USED -1 //FIXME rename?
#define PART_NOT_AVAILABLE -2

    /**
     * is 1 if the specific list MV&references are set to 0,0,-2.
     */
    int mv_cache_clean[2];

    /**
     * number of neighbors (top and/or left) that used 8x8 dct
     */
    int neighbor_transform_size;

    /**
     * block_offset[ 0..23] for frame macroblocks
     * block_offset[24..47] for field macroblocks
     */
    int block_offset[2*(16+8)];

    uint32_t *mb2b_xy; //FIXME are these 4 a good idea?
    uint32_t *mb2b8_xy;
    int b_stride; //FIXME use s->b4_stride
    int b8_stride;

    int mb_linesize;   ///< may be equal to s->linesize or s->linesize*2, for mbaff
    int mb_uvlinesize;

    int emu_edge_width;
    int emu_edge_height;

    int halfpel_flag;
    int thirdpel_flag;

    int unknown_svq3_flag;
    int next_slice_index;

    SPS *sps_buffers[MAX_SPS_COUNT];
    SPS sps; ///< current sps

    PPS *pps_buffers[MAX_PPS_COUNT];
    /**
     * current pps
     */
    PPS pps; //FIXME move to Picture perhaps? (->no) do we need that?

    uint32_t dequant4_buffer[6][52][16];
    uint32_t dequant8_buffer[2][52][64];
    uint32_t (*dequant4_coeff[6])[16];
    uint32_t (*dequant8_coeff[2])[64];
    int dequant_coeff_pps;     ///< reinit tables when pps changes

    int slice_num;
    uint16_t *slice_table_base;
    uint16_t *slice_table;     ///< slice_table_base + 2*mb_stride + 1
    int slice_type;
    int slice_type_nos;        ///< S free slice type (SI/SP are remapped to I/P)
    int slice_type_fixed;

    //interlacing specific flags
    int mb_aff_frame;
    int mb_field_decoding_flag;
    int mb_mbaff;              ///< mb_aff_frame && mb_field_decoding_flag

    DECLARE_ALIGNED_8(uint16_t, sub_mb_type[4]);

    //POC stuff
    int poc_lsb;
    int poc_msb;
    int delta_poc_bottom;
    int delta_poc[2];
    int frame_num;
    int prev_poc_msb;             ///< poc_msb of the last reference pic for POC type 0
    int prev_poc_lsb;             ///< poc_lsb of the last reference pic for POC type 0
    int frame_num_offset;         ///< for POC type 2
    int prev_frame_num_offset;    ///< for POC type 2
    int prev_frame_num;           ///< frame_num of the last pic for POC type 1/2

    /**
     * frame_num for frames or 2*frame_num+1 for field pics.
     */
    int curr_pic_num;

    /**
     * max_frame_num or 2*max_frame_num for field pics.
     */
    int max_pic_num;

    //Weighted pred stuff
    int use_weight;
    int use_weight_chroma;
    int luma_log2_weight_denom;
    int chroma_log2_weight_denom;
    int luma_weight[2][48];
    int luma_offset[2][48];
    int chroma_weight[2][48][2];
    int chroma_offset[2][48][2];
    int implicit_weight[48][48];

    //deblock
    int deblocking_filter;         ///< disable_deblocking_filter_idc with 1<->0
    int slice_alpha_c0_offset;
    int slice_beta_offset;

    int redundant_pic_count;

    int direct_spatial_mv_pred;
    int dist_scale_factor[16];
    int dist_scale_factor_field[2][32];
    int map_col_to_list0[2][16+32];
    int map_col_to_list0_field[2][2][16+32];

    /**
     * num_ref_idx_l0/1_active_minus1 + 1
     */
    unsigned int ref_count[2];   ///< counts frames or fields, depending on current mb mode
    unsigned int list_count;
    Picture *short_ref[32];
    Picture *long_ref[32];
    Picture default_ref_list[2][32]; ///< base reference list for all slices of a coded picture
    Picture ref_list[2][48];         /**< 0..15: frame refs, 16..47: mbaff field refs.
                                          Reordered version of default_ref_list
                                          according to picture reordering in slice header */
    int ref2frm[MAX_SLICES][2][64];  ///< reference to frame number lists, used in the loop filter, the first 2 are for -2,-1
    Picture *delayed_pic[MAX_DELAYED_PIC_COUNT+2]; //FIXME size?
    int outputed_poc;

    /**
     * memory management control operations buffer.
     */
    MMCO mmco[MAX_MMCO_COUNT];
    int mmco_index;

    int long_ref_count;  ///< number of actual long term references
    int short_ref_count; ///< number of actual short term references

    //data partitioning
    GetBitContext intra_gb;
    GetBitContext inter_gb;
    GetBitContext *intra_gb_ptr;
    GetBitContext *inter_gb_ptr;

    DECLARE_ALIGNED_16(DCTELEM, mb[16*24]);
    DCTELEM mb_padding[256];        ///< as mb is addressed by scantable[i] and scantable is uint8_t we can either check that i is not too large or ensure that there is some unused stuff after mb

    /**
     * Cabac
     */
    CABACContext cabac;
    uint8_t      cabac_state[460];
    int          cabac_init_idc;

    /* 0x100 -> non null luma_dc, 0x80/0x40 -> non null chroma_dc (cb/cr), 0x?0 -> chroma_cbp(0,1,2), 0x0? luma_cbp */
    uint16_t     *cbp_table;
    int cbp;
    int top_cbp;
    int left_cbp;
    /* chroma_pred_mode for i4x4 or i16x16, else 0 */
    uint8_t     *chroma_pred_mode_table;
    int         last_qscale_diff;
    int16_t     (*mvd_table[2])[2];
    DECLARE_ALIGNED_8(int16_t, mvd_cache[2][5*8][2]);
    uint8_t     *direct_table;
    uint8_t     direct_cache[5*8];

    uint8_t zigzag_scan[16];
    uint8_t zigzag_scan8x8[64];
    uint8_t zigzag_scan8x8_cavlc[64];
    uint8_t field_scan[16];
    uint8_t field_scan8x8[64];
    uint8_t field_scan8x8_cavlc[64];
    const uint8_t *zigzag_scan_q0;
    const uint8_t *zigzag_scan8x8_q0;
    const uint8_t *zigzag_scan8x8_cavlc_q0;
    const uint8_t *field_scan_q0;
    const uint8_t *field_scan8x8_q0;
    const uint8_t *field_scan8x8_cavlc_q0;

    int x264_build;

    /**
     * @defgroup multithreading Members for slice based multithreading
     * @{
     */
    struct H264Context *thread_context[MAX_THREADS];

    /**
     * current slice number, used to initalize slice_num of each thread/context
     */
    int current_slice;

    /**
     * Max number of threads / contexts.
     * This is equal to AVCodecContext.thread_count unless
     * multithreaded decoding is impossible, in which case it is
     * reduced to 1.
     */
    int max_contexts;

    /**
     *  1 if the single thread fallback warning has already been
     *  displayed, 0 otherwise.
     */
    int single_decode_warning;

    int last_slice_type;
    /** @} */

    int mb_xy;

    uint32_t svq3_watermark_key;

    /**
     * pic_struct in picture timing SEI message
     */
    SEI_PicStructType sei_pic_struct;

    /**
     * dpb_output_delay in picture timing SEI message, see H.264 C.2.2
     */
    int sei_dpb_output_delay;

    /**
     * cpb_removal_delay in picture timing SEI message, see H.264 C.1.2
     */
    int sei_cpb_removal_delay;

    /**
     * recovery_frame_cnt from SEI message
     *
     * Set to -1 if no recovery point SEI message found or to number of frames
     * before playback synchronizes. Frames having recovery point are key
     * frames.
     */
    int sei_recovery_frame_cnt;

    int is_complex;

    int luma_weight_flag[2];   ///< 7.4.3.2 luma_weight_lX_flag
    int chroma_weight_flag[2]; ///< 7.4.3.2 chroma_weight_lX_flag

    // Timestamp stuff
    int sei_buffering_period_present;  ///< Buffering period SEI flag
    int initial_cpb_removal_delay[32]; ///< Initial timestamps for CPBs
}H264Context;

/**
 * Decode SEI
 */
int ff_h264_decode_sei(H264Context *h);

/**
 * Decode SPS
 */
int ff_h264_decode_seq_parameter_set(H264Context *h);

/**
 * Decode PPS
 */
int ff_h264_decode_picture_parameter_set(H264Context *h, int bit_length);

/**
 * Decodes a network abstraction layer unit.
 * @param consumed is the number of bytes used as input
 * @param length is the length of the array
 * @param dst_length is the number of decoded bytes FIXME here or a decode rbsp tailing?
 * @returns decoded bytes, might be src+1 if no escapes
 */
const uint8_t *ff_h264_decode_nal(H264Context *h, const uint8_t *src, int *dst_length, int *consumed, int length);

/**
 * identifies the exact end of the bitstream
 * @return the length of the trailing, or 0 if damaged
 */
int ff_h264_decode_rbsp_trailing(H264Context *h, const uint8_t *src);

#endif /* AVCODEC_H264_H */