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

/*
 * Generic DCT based hybrid video encoder
 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard.
 * Copyright (c) 2002-2004 Michael Niedermayer
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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,
 * 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
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file mpegvideo.h
 * mpegvideo header.
 */

#ifndef AVCODEC_MPEGVIDEO_H
#define AVCODEC_MPEGVIDEO_H

#include "dsputil.h"
#include "bitstream.h"
#include "ratecontrol.h"
#include "parser.h"

#define FRAME_SKIPPED 100 ///< return value for header parsers if frame is not coded

enum OutputFormat {
    FMT_MPEG1,
    FMT_H261,
    FMT_H263,
    FMT_MJPEG,
    FMT_H264,
};

#define EDGE_WIDTH 16

#define MPEG_BUF_SIZE (16 * 1024)

#define QMAT_SHIFT_MMX 16
#define QMAT_SHIFT 22

#define MAX_FCODE 7
#define MAX_MV 2048

#define MAX_THREADS 8

#define MAX_PICTURE_COUNT 32

#define ME_MAP_SIZE 64
#define ME_MAP_SHIFT 3
#define ME_MAP_MV_BITS 11

/* run length table */
#define MAX_RUN    64
#define MAX_LEVEL  64

#define I_TYPE FF_I_TYPE  ///< Intra
#define P_TYPE FF_P_TYPE  ///< Predicted
#define B_TYPE FF_B_TYPE  ///< Bi-dir predicted
#define S_TYPE FF_S_TYPE  ///< S(GMC)-VOP MPEG4
#define SI_TYPE FF_SI_TYPE  ///< Switching Intra
#define SP_TYPE FF_SP_TYPE  ///< Switching Predicted

#define MAX_MB_BYTES (30*16*16*3/8 + 120)

#define INPLACE_OFFSET 16

/* Start codes. */
#define SEQ_END_CODE            0x000001b7
#define SEQ_START_CODE          0x000001b3
#define GOP_START_CODE          0x000001b8
#define PICTURE_START_CODE      0x00000100
#define SLICE_MIN_START_CODE    0x00000101
#define SLICE_MAX_START_CODE    0x000001af
#define EXT_START_CODE          0x000001b5
#define USER_START_CODE         0x000001b2

/**
 * Scantable.
 */
typedef struct ScanTable{
    const uint8_t *scantable;
    uint8_t permutated[64];
    uint8_t raster_end[64];
#ifdef ARCH_POWERPC
                /** Used by dct_quantise_alitvec to find last-non-zero */
    DECLARE_ALIGNED_8(uint8_t, inverse[64]);
#endif
} ScanTable;

/**
 * Picture.
 */
typedef struct Picture{
    FF_COMMON_FRAME

    /**
     * halfpel luma planes.
     */
    uint8_t *interpolated[3];
    int16_t (*motion_val_base[2])[2];
    uint32_t *mb_type_base;
#define MB_TYPE_INTRA MB_TYPE_INTRA4x4 //default mb_type if theres just one type
#define IS_INTRA4x4(a)   ((a)&MB_TYPE_INTRA4x4)
#define IS_INTRA16x16(a) ((a)&MB_TYPE_INTRA16x16)
#define IS_PCM(a)        ((a)&MB_TYPE_INTRA_PCM)
#define IS_INTRA(a)      ((a)&7)
#define IS_INTER(a)      ((a)&(MB_TYPE_16x16|MB_TYPE_16x8|MB_TYPE_8x16|MB_TYPE_8x8))
#define IS_SKIP(a)       ((a)&MB_TYPE_SKIP)
#define IS_INTRA_PCM(a)  ((a)&MB_TYPE_INTRA_PCM)
#define IS_INTERLACED(a) ((a)&MB_TYPE_INTERLACED)
#define IS_DIRECT(a)     ((a)&MB_TYPE_DIRECT2)
#define IS_GMC(a)        ((a)&MB_TYPE_GMC)
#define IS_16X16(a)      ((a)&MB_TYPE_16x16)
#define IS_16X8(a)       ((a)&MB_TYPE_16x8)
#define IS_8X16(a)       ((a)&MB_TYPE_8x16)
#define IS_8X8(a)        ((a)&MB_TYPE_8x8)
#define IS_SUB_8X8(a)    ((a)&MB_TYPE_16x16) //note reused
#define IS_SUB_8X4(a)    ((a)&MB_TYPE_16x8)  //note reused
#define IS_SUB_4X8(a)    ((a)&MB_TYPE_8x16)  //note reused
#define IS_SUB_4X4(a)    ((a)&MB_TYPE_8x8)   //note reused
#define IS_ACPRED(a)     ((a)&MB_TYPE_ACPRED)
#define IS_QUANT(a)      ((a)&MB_TYPE_QUANT)
#define IS_DIR(a, part, list) ((a) & (MB_TYPE_P0L0<<((part)+2*(list))))
#define USES_LIST(a, list) ((a) & ((MB_TYPE_P0L0|MB_TYPE_P1L0)<<(2*(list)))) ///< does this mb use listX, note does not work if subMBs
#define HAS_CBP(a)        ((a)&MB_TYPE_CBP)

    int field_poc[2];           ///< h264 top/bottom POC
    int poc;                    ///< h264 frame POC
    int frame_num;              ///< h264 frame_num (raw frame_num from slice header)
    int pic_id;                 /**< h264 pic_num (short -> no wrap version of pic_num,
                                     pic_num & max_pic_num; long -> long_pic_num) */
    int long_ref;               ///< 1->long term reference 0->short term reference
    int ref_poc[2][16];         ///< h264 POCs of the frames used as reference
    int ref_count[2];           ///< number of entries in ref_poc

    int mb_var_sum;             ///< sum of MB variance for current frame
    int mc_mb_var_sum;          ///< motion compensated MB variance for current frame
    uint16_t *mb_var;           ///< Table for MB variances
    uint16_t *mc_mb_var;        ///< Table for motion compensated MB variances
    uint8_t *mb_mean;           ///< Table for MB luminance
    int32_t *mb_cmp_score;      ///< Table for MB cmp scores, for mb decision FIXME remove
    int b_frame_score;          /* */
} Picture;

struct MpegEncContext;

/**
 * Motion estimation context.
 */
typedef struct MotionEstContext{
    AVCodecContext *avctx;
    int skip;                          ///< set if ME is skipped for the current MB
    int co_located_mv[4][2];           ///< mv from last P-frame for direct mode ME
    int direct_basis_mv[4][2];
    uint8_t *scratchpad;               ///< data area for the ME algo, so that the ME does not need to malloc/free
    uint8_t *best_mb;
    uint8_t *temp_mb[2];
    uint8_t *temp;
    int best_bits;
    uint32_t *map;                     ///< map to avoid duplicate evaluations
    uint32_t *score_map;               ///< map to store the scores
    int map_generation;
    int pre_penalty_factor;
    int penalty_factor;                /*!< an estimate of the bits required to
                                        code a given mv value, e.g. (1,0) takes
                                        more bits than (0,0). We have to
                                        estimate whether any reduction in
                                        residual is worth the extra bits. */
    int sub_penalty_factor;
    int mb_penalty_factor;
    int flags;
    int sub_flags;
    int mb_flags;
    int pre_pass;                      ///< = 1 for the pre pass
    int dia_size;
    int xmin;
    int xmax;
    int ymin;
    int ymax;
    int pred_x;
    int pred_y;
    uint8_t *src[4][4];
    uint8_t *ref[4][4];
    int stride;
    int uvstride;
    /* temp variables for picture complexity calculation */
    int mc_mb_var_sum_temp;
    int mb_var_sum_temp;
    int scene_change_score;
/*    cmp, chroma_cmp;*/
    op_pixels_func (*hpel_put)[4];
    op_pixels_func (*hpel_avg)[4];
    qpel_mc_func (*qpel_put)[16];
    qpel_mc_func (*qpel_avg)[16];
    uint8_t (*mv_penalty)[MAX_MV*2+1];  ///< amount of bits needed to encode a MV
    uint8_t *current_mv_penalty;
    int (*sub_motion_search)(struct MpegEncContext * s,
                                  int *mx_ptr, int *my_ptr, int dmin,
                                  int src_index, int ref_index,
                                  int size, int h);
}MotionEstContext;

/**
 * MpegEncContext.
 */
typedef struct MpegEncContext {
    struct AVCodecContext *avctx;
    /* the following parameters must be initialized before encoding */
    int width, height;///< picture size. must be a multiple of 16
    int gop_size;
    int intra_only;   ///< if true, only intra pictures are generated
    int bit_rate;     ///< wanted bit rate
    enum OutputFormat out_format; ///< output format
    int h263_pred;    ///< use mpeg4/h263 ac/dc predictions

/* the following codec id fields are deprecated in favor of codec_id */
    int h263_plus;    ///< h263 plus headers
    int h263_msmpeg4; ///< generate MSMPEG4 compatible stream (deprecated, use msmpeg4_version instead)
    int h263_flv;     ///< use flv h263 header

    enum CodecID codec_id;     /* see CODEC_ID_xxx */
    int fixed_qscale; ///< fixed qscale if non zero
    int encoding;     ///< true if we are encoding (vs decoding)
    int flags;        ///< AVCodecContext.flags (HQ, MV4, ...)
    int flags2;       ///< AVCodecContext.flags2
    int max_b_frames; ///< max number of b-frames for encoding
    int luma_elim_threshold;
    int chroma_elim_threshold;
    int strict_std_compliance; ///< strictly follow the std (MPEG4, ...)
    int workaround_bugs;       ///< workaround bugs in encoders which cannot be detected automatically
    int codec_tag;             ///< internal codec_tag upper case converted from avctx codec_tag
    int stream_codec_tag;      ///< internal stream_codec_tag upper case converted from avctx stream_codec_tag
    /* the following fields are managed internally by the encoder */

    /** bit output */
    PutBitContext pb;

    /* sequence parameters */
    int context_initialized;
    int input_picture_number;  ///< used to set pic->display_picture_number, should not be used for/by anything else
    int coded_picture_number;  ///< used to set pic->coded_picture_number, should not be used for/by anything else
    int picture_number;       //FIXME remove, unclear definition
    int picture_in_gop_number; ///< 0-> first pic in gop, ...
    int b_frames_since_non_b;  ///< used for encoding, relative to not yet reordered input
    int64_t user_specified_pts;///< last non zero pts from AVFrame which was passed into avcodec_encode_video()
    int mb_width, mb_height;   ///< number of MBs horizontally & vertically
    int mb_stride;             ///< mb_width+1 used for some arrays to allow simple addressing of left & top MBs without sig11
    int b8_stride;             ///< 2*mb_width+1 used for some 8x8 block arrays to allow simple addressing
    int b4_stride;             ///< 4*mb_width+1 used for some 4x4 block arrays to allow simple addressing
    int h_edge_pos, v_edge_pos;///< horizontal / vertical position of the right/bottom edge (pixel replication)
    int mb_num;                ///< number of MBs of a picture
    int linesize;              ///< line size, in bytes, may be different from width
    int uvlinesize;            ///< line size, for chroma in bytes, may be different from width
    Picture *picture;          ///< main picture buffer
    Picture **input_picture;   ///< next pictures on display order for encoding
    Picture **reordered_input_picture; ///< pointer to the next pictures in codedorder for encoding

    int start_mb_y;            ///< start mb_y of this thread (so current thread should process start_mb_y <= row < end_mb_y)
    int end_mb_y;              ///< end   mb_y of this thread (so current thread should process start_mb_y <= row < end_mb_y)
    struct MpegEncContext *thread_context[MAX_THREADS];

    /**
     * copy of the previous picture structure.
     * note, linesize & data, might not match the previous picture (for field pictures)
     */
    Picture last_picture;

    /**
     * copy of the next picture structure.
     * note, linesize & data, might not match the next picture (for field pictures)
     */
    Picture next_picture;

    /**
     * copy of the source picture structure for encoding.
     * note, linesize & data, might not match the source picture (for field pictures)
     */
    Picture new_picture;

    /**
     * copy of the current picture structure.
     * note, linesize & data, might not match the current picture (for field pictures)
     */
    Picture current_picture;    ///< buffer to store the decompressed current picture

    Picture *last_picture_ptr;     ///< pointer to the previous picture.
    Picture *next_picture_ptr;     ///< pointer to the next picture (for bidir pred)
    Picture *current_picture_ptr;  ///< pointer to the current picture