mpegvideo.h

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

    uint8_t *visualization_buffer[3]; //< temporary buffer vor MV visualization
    int last_dc[3];                ///< last DC values for MPEG1
    int16_t *dc_val_base;
    int16_t *dc_val[3];            ///< used for mpeg4 DC prediction, all 3 arrays must be continuous
    int16_t dc_cache[4*5];
    int y_dc_scale, c_dc_scale;
    const uint8_t *y_dc_scale_table;     ///< qscale -> y_dc_scale table
    const uint8_t *c_dc_scale_table;     ///< qscale -> c_dc_scale table
    const uint8_t *chroma_qscale_table;  ///< qscale -> chroma_qscale (h263)
    uint8_t *coded_block_base;
    uint8_t *coded_block;          ///< used for coded block pattern prediction (msmpeg4v3, wmv1)
    int16_t (*ac_val_base)[16];
    int16_t (*ac_val[3])[16];      ///< used for for mpeg4 AC prediction, all 3 arrays must be continuous
    int ac_pred;
    uint8_t *prev_pict_types;     ///< previous picture types in bitstream order, used for mb skip
#define PREV_PICT_TYPES_BUFFER_SIZE 256
    int mb_skipped;                ///< MUST BE SET only during DECODING
    uint8_t *mbskip_table;        /**< used to avoid copy if macroblock skipped (for black regions for example)
                                   and used for b-frame encoding & decoding (contains skip table of next P Frame) */
    uint8_t *mbintra_table;       ///< used to avoid setting {ac, dc, cbp}-pred stuff to zero on inter MB decoding
    uint8_t *cbp_table;           ///< used to store cbp, ac_pred for partitioned decoding
    uint8_t *pred_dir_table;      ///< used to store pred_dir for partitioned decoding
    uint8_t *allocated_edge_emu_buffer;
    uint8_t *edge_emu_buffer;     ///< points into the middle of allocated_edge_emu_buffer
    uint8_t *rd_scratchpad;       ///< scratchpad for rate distortion mb decision
    uint8_t *obmc_scratchpad;
    uint8_t *b_scratchpad;        ///< scratchpad used for writing into write only buffers

    int qscale;                 ///< QP
    int chroma_qscale;          ///< chroma QP
    unsigned int lambda;        ///< lagrange multipler used in rate distortion
    unsigned int lambda2;       ///< (lambda*lambda) >> FF_LAMBDA_SHIFT
    int *lambda_table;
    int adaptive_quant;         ///< use adaptive quantization
    int dquant;                 ///< qscale difference to prev qscale
    int pict_type;              ///< I_TYPE, P_TYPE, B_TYPE, ...
    int last_pict_type; //FIXME removes
    int last_non_b_pict_type;   ///< used for mpeg4 gmc b-frames & ratecontrol
    int dropable;
    int frame_rate_index;
    int last_lambda_for[5];     ///< last lambda for a specific pict type
    int skipdct;                ///< skip dct and code zero residual

    /* motion compensation */
    int unrestricted_mv;        ///< mv can point outside of the coded picture
    int h263_long_vectors;      ///< use horrible h263v1 long vector mode
    int decode;                 ///< if 0 then decoding will be skipped (for encoding b frames for example)

    DSPContext dsp;             ///< pointers for accelerated dsp functions
    int f_code;                 ///< forward MV resolution
    int b_code;                 ///< backward MV resolution for B Frames (mpeg4)
    int16_t (*p_mv_table_base)[2];
    int16_t (*b_forw_mv_table_base)[2];
    int16_t (*b_back_mv_table_base)[2];
    int16_t (*b_bidir_forw_mv_table_base)[2];
    int16_t (*b_bidir_back_mv_table_base)[2];
    int16_t (*b_direct_mv_table_base)[2];
    int16_t (*p_field_mv_table_base[2][2])[2];
    int16_t (*b_field_mv_table_base[2][2][2])[2];
    int16_t (*p_mv_table)[2];            ///< MV table (1MV per MB) p-frame encoding
    int16_t (*b_forw_mv_table)[2];       ///< MV table (1MV per MB) forward mode b-frame encoding
    int16_t (*b_back_mv_table)[2];       ///< MV table (1MV per MB) backward mode b-frame encoding
    int16_t (*b_bidir_forw_mv_table)[2]; ///< MV table (1MV per MB) bidir mode b-frame encoding
    int16_t (*b_bidir_back_mv_table)[2]; ///< MV table (1MV per MB) bidir mode b-frame encoding
    int16_t (*b_direct_mv_table)[2];     ///< MV table (1MV per MB) direct mode b-frame encoding
    int16_t (*p_field_mv_table[2][2])[2];   ///< MV table (2MV per MB) interlaced p-frame encoding
    int16_t (*b_field_mv_table[2][2][2])[2];///< MV table (4MV per MB) interlaced b-frame encoding
    uint8_t (*p_field_select_table[2]);
    uint8_t (*b_field_select_table[2][2]);
    int me_method;                       ///< ME algorithm
    int mv_dir;
#define MV_DIR_FORWARD   1
#define MV_DIR_BACKWARD  2
#define MV_DIRECT        4 ///< bidirectional mode where the difference equals the MV of the last P/S/I-Frame (mpeg4)
    int mv_type;
#define MV_TYPE_16X16       0   ///< 1 vector for the whole mb
#define MV_TYPE_8X8         1   ///< 4 vectors (h263, mpeg4 4MV)
#define MV_TYPE_16X8        2   ///< 2 vectors, one per 16x8 block
#define MV_TYPE_FIELD       3   ///< 2 vectors, one per field
#define MV_TYPE_DMV         4   ///< 2 vectors, special mpeg2 Dual Prime Vectors
    /**motion vectors for a macroblock
       first coordinate : 0 = forward 1 = backward
       second "         : depend on type
       third  "         : 0 = x, 1 = y
    */
    int mv[2][4][2];
    int field_select[2][2];
    int last_mv[2][2][2];             ///< last MV, used for MV prediction in MPEG1 & B-frame MPEG4
    uint8_t *fcode_tab;               ///< smallest fcode needed for each MV
    int16_t direct_scale_mv[2][64];   ///< precomputed to avoid divisions in ff_mpeg4_set_direct_mv

    MotionEstContext me;

    int no_rounding;  /**< apply no rounding to motion compensation (MPEG4, msmpeg4, ...)
                        for b-frames rounding mode is always 0 */

    int hurry_up;     /**< when set to 1 during decoding, b frames will be skipped
                         when set to 2 idct/dequant will be skipped too */

    /* macroblock layer */
    int mb_x, mb_y;
    int mb_skip_run;
    int mb_intra;
    uint16_t *mb_type;           ///< Table for candidate MB types for encoding
#define CANDIDATE_MB_TYPE_INTRA    0x01
#define CANDIDATE_MB_TYPE_INTER    0x02
#define CANDIDATE_MB_TYPE_INTER4V  0x04
#define CANDIDATE_MB_TYPE_SKIPPED   0x08
//#define MB_TYPE_GMC      0x10

#define CANDIDATE_MB_TYPE_DIRECT   0x10
#define CANDIDATE_MB_TYPE_FORWARD  0x20
#define CANDIDATE_MB_TYPE_BACKWARD 0x40
#define CANDIDATE_MB_TYPE_BIDIR    0x80

#define CANDIDATE_MB_TYPE_INTER_I    0x100
#define CANDIDATE_MB_TYPE_FORWARD_I  0x200
#define CANDIDATE_MB_TYPE_BACKWARD_I 0x400
#define CANDIDATE_MB_TYPE_BIDIR_I    0x800

#define CANDIDATE_MB_TYPE_DIRECT0    0x1000

    int block_index[6]; ///< index to current MB in block based arrays with edges
    int block_wrap[6];
    uint8_t *dest[3];

    int *mb_index2xy;        ///< mb_index -> mb_x + mb_y*mb_stride

    /** matrix transmitted in the bitstream */
    uint16_t intra_matrix[64];
    uint16_t chroma_intra_matrix[64];
    uint16_t inter_matrix[64];
    uint16_t chroma_inter_matrix[64];
#define QUANT_BIAS_SHIFT 8
    int intra_quant_bias;    ///< bias for the quantizer
    int inter_quant_bias;    ///< bias for the quantizer
    int min_qcoeff;          ///< minimum encodable coefficient
    int max_qcoeff;          ///< maximum encodable coefficient
    int ac_esc_length;       ///< num of bits needed to encode the longest esc
    uint8_t *intra_ac_vlc_length;
    uint8_t *intra_ac_vlc_last_length;
    uint8_t *inter_ac_vlc_length;
    uint8_t *inter_ac_vlc_last_length;
    uint8_t *luma_dc_vlc_length;
    uint8_t *chroma_dc_vlc_length;
#define UNI_AC_ENC_INDEX(run,level) ((run)*128 + (level))

    int coded_score[8];

    /** precomputed matrix (combine qscale and DCT renorm) */
    int (*q_intra_matrix)[64];
    int (*q_inter_matrix)[64];
    /** identical to the above but for MMX & these are not permutated, second 64 entries are bias*/
    uint16_t (*q_intra_matrix16)[2][64];
    uint16_t (*q_inter_matrix16)[2][64];
    int block_last_index[12];  ///< last non zero coefficient in block
    /* scantables */
    DECLARE_ALIGNED_8(ScanTable, intra_scantable);
    ScanTable intra_h_scantable;
    ScanTable intra_v_scantable;
    ScanTable inter_scantable; ///< if inter == intra then intra should be used to reduce tha cache usage

    /* noise reduction */
    int (*dct_error_sum)[64];
    int dct_count[2];
    uint16_t (*dct_offset)[64];

    void *opaque;              ///< private data for the user

    /* bit rate control */
    int64_t wanted_bits;
    int64_t total_bits;
    int frame_bits;                ///< bits used for the current frame
    int next_lambda;               ///< next lambda used for retrying to encode a frame
    RateControlContext rc_context; ///< contains stuff only accessed in ratecontrol.c

    /* statistics, used for 2-pass encoding */
    int mv_bits;
    int header_bits;
    int i_tex_bits;
    int p_tex_bits;
    int i_count;
    int f_count;
    int b_count;
    int skip_count;
    int misc_bits; ///< cbp, mb_type
    int last_bits; ///< temp var used for calculating the above vars

    /* error concealment / resync */
    int error_count;
    uint8_t *error_status_table;       ///< table of the error status of each MB
#define VP_START            1          ///< current MB is the first after a resync marker
#define AC_ERROR            2
#define DC_ERROR            4
#define MV_ERROR            8
#define AC_END              16
#define DC_END              32
#define MV_END              64
//FIXME some prefix?

    int resync_mb_x;                 ///< x position of last resync marker
    int resync_mb_y;                 ///< y position of last resync marker
    GetBitContext last_resync_gb;    ///< used to search for the next resync marker
    int mb_num_left;                 ///< number of MBs left in this video packet (for partitioned Slices only)
    int next_p_frame_damaged;        ///< set if the next p frame is damaged, to avoid showing trashed b frames
    int error_resilience;

    ParseContext parse_context;

    /* H.263 specific */
    int gob_index;
    int obmc;                       ///< overlapped block motion compensation

    /* H.263+ specific */
    int umvplus;                    ///< == H263+ && unrestricted_mv
    int h263_aic;                   ///< Advanded INTRA Coding (AIC)
    int h263_aic_dir;               ///< AIC direction: 0 = left, 1 = top
    int h263_slice_structured;
    int alt_inter_vlc;              ///< alternative inter vlc
    int modified_quant;
    int loop_filter;
    int custom_pcf;

    /* mpeg4 specific */
    int time_increment_bits;        ///< number of bits to represent the fractional part of time
    int last_time_base;
    int time_base;                  ///< time in seconds of last I,P,S Frame
    int64_t time;                   ///< time of current frame
    int64_t last_non_b_time;
    uint16_t pp_time;               ///< time distance between the last 2 p,s,i frames
    uint16_t pb_time;               ///< time distance between the last b and p,s,i frame
    uint16_t pp_field_time;
    uint16_t pb_field_time;         ///< like above, just for interlaced
    int shape;
    int vol_sprite_usage;
    int sprite_width;
    int sprite_height;
    int sprite_left;
    int sprite_top;
    int sprite_brightness_change;
    int num_sprite_warping_points;
    int real_sprite_warping_points;
    int sprite_offset[2][2];         ///< sprite offset[isChroma][isMVY]
    int sprite_delta[2][2];          ///< sprite_delta [isY][isMVY]
    int sprite_shift[2];             ///< sprite shift [isChroma]
    int mcsel;
    int quant_precision;
    int quarter_sample;              ///< 1->qpel, 0->half pel ME/MC
    int scalability;
    int hierachy_type;
    int enhancement_type;
    int new_pred;
    int reduced_res_vop;
    int aspect_ratio_info; //FIXME remove
    int sprite_warping_accuracy;
    int low_latency_sprite;
    int data_partitioning;           ///< data partitioning flag from header
    int partitioned_frame;           ///< is current frame partitioned
    int rvlc;                        ///< reversible vlc
    int resync_marker;               ///< could this stream contain resync markers
    int low_delay;                   ///< no reordering needed / has no b-frames
    int vo_type;
    int vol_control_parameters;      ///< does the stream contain the low_delay flag, used to workaround buggy encoders
    int intra_dc_threshold;          ///< QP above whch the ac VLC should be used for intra dc
    int use_intra_dc_vlc;
    PutBitContext tex_pb;            ///< used for data partitioned VOPs
    PutBitContext pb2;               ///< used for data partitioned VOPs
    int mpeg_quant;
    int t_frame;                       ///< time distance of first I -> B, used for interlaced b frames
    int padding_bug_score;             ///< used to detect the VERY common padding bug in MPEG4

    /* divx specific, used to workaround (many) bugs in divx5 */
    int divx_version;
    int divx_build;
    int divx_packed;
    uint8_t *bitstream_buffer; //Divx 5.01 puts several frames in a single one, this is used to reorder them
    int bitstream_buffer_size;
    unsigned int allocated_bitstream_buffer_size;

    int xvid_build;

    /* lavc specific stuff, used to workaround bugs in libavcodec */
    int lavc_build;

    /* RV10 specific */
    int rv10_version; ///< RV10 version: 0 or 3
    int rv10_first_dc_coded[3];

    /* MJPEG specific */
    struct MJpegContext *mjpeg_ctx;
    int mjpeg_vsample[3];       ///< vertical sampling factors, default = {2, 1, 1}
    int mjpeg_hsample[3];       ///< horizontal sampling factors, default = {2, 1, 1}

    /* MSMPEG4 specific */
    int mv_table_index;
    int rl_table_index;
    int rl_chroma_table_index;
    int dc_table_index;
    int use_skip_mb_code;
    int slice_height;      ///< in macroblocks