* QP store stride\     * - encoding: unused\     * - decoding: set by lavc\     */\    int qstride;\\    /**\     * mbskip_table[mb]>=1 if MB didnt change\     * stride= mb_width = (width+15)>>4\     * - encoding: unused\     * - decoding: set by lavc\     */\    uint8_t *mbskip_table;\\    /**\     * Motion vector table\     * - encoding: unused\     * - decoding: set by lavc\     */\    int16_t (*motion_val[2])[2];\\    /**\     * Macroblock type table\     * mb_type_base + mb_width + 2\     * - encoding: unused\     * - decoding: set by lavc\     */\    uint32_t *mb_type;\\    /**\     * Macroblock size: (0->16x16, 1->8x8, 2-> 4x4, 3-> 2x2)\     * - encoding: unused\     * - decoding: set by lavc\     */\    uint8_t motion_subsample_log2;\\    /**\     * for some private data of the user\     * - encoding: unused\     * - decoding: set by user\     */\    void *opaque;\\    /**\     * error\     * - encoding: set by lavc if flags&CODEC_FLAG_PSNR\     * - decoding: unused\     */\    uint64_t error[4];\\    /**\     * type of the buffer (to keep track of who has to dealloc data[*])\     * - encoding: set by the one who allocs it\     * - decoding: set by the one who allocs it\     * Note: user allocated (direct rendering) & internal buffers can not coexist currently\     */\    int type;\    \    /**\     * when decoding, this signal how much the picture must be delayed.\     * extra_delay = repeat_pict / (2*fps)\     * - encoding: unused\     * - decoding: set by lavc\     */\    int repeat_pict;\    \    /**\     * \     */\    int qscale_type;\    \    /**\     * The content of the picture is interlaced.\     * - encoding: set by user\     * - decoding: set by lavc (default 0)\     */\    int interlaced_frame;\    \    /**\     * if the content is interlaced, is top field displayed first.\     * - encoding: set by user\     * - decoding: set by lavc\     */\    int top_field_first;\    \    /**\     * Pan scan.\     * - encoding: set by user\     * - decoding: set by lavc\     */\    AVPanScan *pan_scan;\    \    /**\     * tell user application that palette has changed from previous frame.\     * - encoding: ??? (no palette-enabled encoder yet)\     * - decoding: set by lavc (default 0)\     */\    int palette_has_changed;\    \    /**\     * Codec suggestion on buffer type if != 0\     * - encoding: unused\     * - decoding: set by lavc (before get_buffer() call))\     */\    int buffer_hints;\\    /**\     * DCT coeffitients\     * - encoding: unused\     * - decoding: set by lavc\     */\    short *dct_coeff;\#define FF_QSCALE_TYPE_MPEG1	0#define FF_QSCALE_TYPE_MPEG2	1#define FF_BUFFER_TYPE_INTERNAL 1#define FF_BUFFER_TYPE_USER     2 ///< Direct rendering buffers (image is (de)allocated by user)#define FF_BUFFER_TYPE_SHARED   4 ///< buffer from somewher else, dont dealloc image (data/base)#define FF_BUFFER_TYPE_COPY     8 ///< just a (modified) copy of some other buffer, dont dealloc anything#define FF_I_TYPE 1 // Intra#define FF_P_TYPE 2 // Predicted#define FF_B_TYPE 3 // Bi-dir predicted#define FF_S_TYPE 4 // S(GMC)-VOP MPEG4#define FF_SI_TYPE 5#define FF_SP_TYPE 6#define FF_BUFFER_HINTS_VALID    0x01 // Buffer hints value is meaningful (if 0 ignore)#define FF_BUFFER_HINTS_READABLE 0x02 // Codec will read from buffer#define FF_BUFFER_HINTS_PRESERVE 0x04 // User must not alter buffer content#define FF_BUFFER_HINTS_REUSABLE 0x08 // Codec will reuse the buffer (update)/** * Audio Video Frame. */typedef struct AVFrame {    FF_COMMON_FRAME} AVFrame;#define DEFAULT_FRAME_RATE_BASE 1001000/** * Used by av_log */typedef struct AVCLASS AVClass;struct AVCLASS {    const char* class_name;    const char* (*item_name)(void*); /* actually passing a pointer to an AVCodecContext					or AVFormatContext, which begin with an AVClass.					Needed because av_log is in libavcodec and has no visibility					of AVIn/OutputFormat */};/** * main external api structure. */typedef struct AVCodecContext {    /**     * Info on struct for av_log     * - set by avcodec_alloc_context     */    AVClass *av_class;    /**     * the average bitrate.     * - encoding: set by user. unused for constant quantizer encoding     * - decoding: set by lavc. 0 or some bitrate if this info is available in the stream      */    int bit_rate;    /**     * number of bits the bitstream is allowed to diverge from the reference.     *           the reference can be CBR (for CBR pass1) or VBR (for pass2)     * - encoding: set by user. unused for constant quantizer encoding     * - decoding: unused     */    int bit_rate_tolerance;     /**     * CODEC_FLAG_*.     * - encoding: set by user.     * - decoding: set by user.     */    int flags;    /**     * some codecs needs additionnal format info. It is stored here     * - encoding: set by user.      * - decoding: set by lavc. (FIXME is this ok?)     */    int sub_id;    /**     * motion estimation algorithm used for video coding.     * - encoding: MUST be set by user.     * - decoding: unused     */    int me_method;    /**     * some codecs need / can use extra-data like huffman tables.     * mjpeg: huffman tables     * rv10: additional flags     * mpeg4: global headers (they can be in the bitstream or here)     * - encoding: set/allocated/freed by lavc.     * - decoding: set/allocated/freed by user.     */    void *extradata;    int extradata_size;        /* video only */    /**     * frames per sec multiplied by frame_rate_base.     * for variable fps this is the precission, so if the timestamps      * can be specified in msec precssion then this is 1000*frame_rate_base     * - encoding: MUST be set by user     * - decoding: set by lavc. 0 or the frame_rate if available     */    int frame_rate;        /**     * width / height.     * - encoding: MUST be set by user.      * - decoding: set by user if known, codec should override / dynamically change if needed     */    int width, height;    #define FF_ASPECT_EXTENDED 15    /**     * the number of pictures in a group of pitures, or 0 for intra_only.     * - encoding: set by user.     * - decoding: unused     */    int gop_size;    /**     * pixel format, see PIX_FMT_xxx.     * - encoding: FIXME: used by ffmpeg to decide whether an pix_fmt     *                    conversion is in order. This only works for     *                    codecs with one supported pix_fmt, we should     *                    do something for a generic case as well.     * - decoding: set by lavc.     */    enum PixelFormat pix_fmt;     /**     * Frame rate emulation. If not zero lower layer (i.e. format handler)      * has to read frames at native frame rate.     * - encoding: set by user.     * - decoding: unused.     */    int rate_emu;           /**     * if non NULL, 'draw_horiz_band' is called by the libavcodec     * decoder to draw an horizontal band. It improve cache usage. Not     * all codecs can do that. You must check the codec capabilities     * before     * - encoding: unused     * - decoding: set by user.     * @param height the height of the slice     * @param y the y position of the slice     * @param type 1->top field, 2->bottom field, 3->frame     * @param offset offset into the AVFrame.data from which the slice should be read     */    void (*draw_horiz_band)(struct AVCodecContext *s,                            const AVFrame *src, int offset[4],                            int y, int type, int height);    /* audio only */    int sample_rate; ///< samples per sec     int channels;    int sample_fmt;  ///< sample format, currenly unused     /* the following data should not be initialized */    int frame_size;     ///< in samples, initialized when calling 'init'     int frame_number;   ///< audio or video frame number     int real_pict_num;  ///< returns the real picture number of previous encoded frame         /**     * number of frames the decoded output will be delayed relative to      * the encoded input.     * - encoding: set by lavc.     * - decoding: unused     */    int delay;        /* - encoding parameters */    float qcompress;  ///< amount of qscale change between easy & hard scenes (0.0-1.0)    float qblur;      ///< amount of qscale smoothing over time (0.0-1.0)         /**     * minimum quantizer.     * - encoding: set by user.     * - decoding: unused     */    int qmin;    /**     * maximum quantizer.     * - encoding: set by user.     * - decoding: unused     */    int qmax;    /**     * maximum quantizer difference etween frames.     * - encoding: set by user.     * - decoding: unused     */    int max_qdiff;    /**     * maximum number of b frames between non b frames.     * note: the output will be delayed by max_b_frames+1 relative to the input     * - encoding: set by user.     * - decoding: unused     */    int max_b_frames;    /**     * qscale factor between ip and b frames.     * - encoding: set by user.     * - decoding: unused     */    float b_quant_factor;        /** obsolete FIXME remove */    int rc_strategy;    int b_frame_strategy;    /**     * hurry up amount.     * - encoding: unused     * - decoding: set by user. 1-> skip b frames, 2-> skip idct/dequant too, 5-> skip everything except header     */    int hurry_up;        struct AVCodec *codec;        void *priv_data;    /* unused, FIXME remove*/    int rtp_mode;        int rtp_payload_size;   /* The size of the RTP payload, the coder will  */                            /* do it's best to deliver a chunk with size    */                            /* below rtp_payload_size, the chunk will start */                            /* with a start code on some codecs like H.263  */                            /* This doesn't take account of any particular  */                            /* headers inside the transmited RTP payload    */        /* The RTP callcack: This function is called  */    /* every time the encoder as a packet to send */    /* Depends on the encoder if the data starts  */    /* with a Start Code (it should) H.263 does   */    void (*rtp_callback)(void *data, int size, int packet_number);     /* statistics, used for 2-pass encoding */    int mv_bits;    int header_bits;    int i_tex_bits;    int p_tex_bits;    int i_count;    int p_count;    int skip_count;    int misc_bits;        /**     * number of bits used for the previously encoded frame.     * - encoding: set by lavc     * - decoding: unused     */    int frame_bits;    /**     * private data of the user, can be used to carry app specific stuff.     * - encoding: set by user     * - decoding: set by user     */    void *opaque;    char codec_name[32];    enum CodecType codec_type; /* see CODEC_TYPE_xxx */    enum CodecID codec_id; /* see CODEC_ID_xxx */        /**     * fourcc (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A').     * this is used to workaround some encoder bugs     * - encoding: set by user, if not then the default based on codec_id will be used     * - decoding: set by user, will be converted to upper case by lavc during init     */    unsigned int codec_tag;        /**     * workaround bugs in encoders which sometimes cannot be detected automatically.     * - encoding: unused     * - decoding: set by user     */    int workaround_bugs;#define FF_BUG_AUTODETECT       1  ///< autodetection#define FF_BUG_OLD_MSMPEG4      2#define FF_BUG_XVID_ILACE       4#define FF_BUG_UMP4             8#define FF_BUG_NO_PADDING       16#define FF_BUG_AC_VLC           0  ///< will be removed, libavcodec can now handle these non compliant files by default#define FF_BUG_QPEL_CHROMA      64#define FF_BUG_STD_QPEL         128#define FF_BUG_QPEL_CHROMA2     256#define FF_BUG_DIRECT_BLOCKSIZE 512#define FF_BUG_EDGE             1024#define FF_BUG_HPEL_CHROMA      2048//#define FF_BUG_FAKE_SCALABILITY 16 //autodetection should work 100%            /**     * luma single coeff elimination threshold.     * - encoding: set by user     * - decoding: unused     */    int luma_elim_threshold;        /**     * chroma single coeff elimination threshold.     * - encoding: set by user     * - decoding: unused     */    int chroma_elim_threshold;