avcodec.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

 */
#define CODEC_CAP_SMALL_LAST_FRAME 0x0040

//The following defines may change, don't expect compatibility if you use them.
#define MB_TYPE_INTRA4x4   0x0001
#define MB_TYPE_INTRA16x16 0x0002 //FIXME H.264-specific
#define MB_TYPE_INTRA_PCM  0x0004 //FIXME H.264-specific
#define MB_TYPE_16x16      0x0008
#define MB_TYPE_16x8       0x0010
#define MB_TYPE_8x16       0x0020
#define MB_TYPE_8x8        0x0040
#define MB_TYPE_INTERLACED 0x0080
#define MB_TYPE_DIRECT2    0x0100 //FIXME
#define MB_TYPE_ACPRED     0x0200
#define MB_TYPE_GMC        0x0400
#define MB_TYPE_SKIP       0x0800
#define MB_TYPE_P0L0       0x1000
#define MB_TYPE_P1L0       0x2000
#define MB_TYPE_P0L1       0x4000
#define MB_TYPE_P1L1       0x8000
#define MB_TYPE_L0         (MB_TYPE_P0L0 | MB_TYPE_P1L0)
#define MB_TYPE_L1         (MB_TYPE_P0L1 | MB_TYPE_P1L1)
#define MB_TYPE_L0L1       (MB_TYPE_L0   | MB_TYPE_L1)
#define MB_TYPE_QUANT      0x00010000
#define MB_TYPE_CBP        0x00020000
//Note bits 24-31 are reserved for codec specific use (h264 ref0, mpeg1 0mv, ...)

/**
 * Pan Scan area.
 * This specifies the area which should be displayed.
 * Note there may be multiple such areas for one frame.
 */
typedef struct AVPanScan{
    /**
     * id
     * - encoding: Set by user.
     * - decoding: Set by libavcodec.
     */
    int id;

    /**
     * width and height in 1/16 pel
     * - encoding: Set by user.
     * - decoding: Set by libavcodec.
     */
    int width;
    int height;

    /**
     * position of the top left corner in 1/16 pel for up to 3 fields/frames
     * - encoding: Set by user.
     * - decoding: Set by libavcodec.
     */
    int16_t position[3][2];
}AVPanScan;

#define FF_COMMON_FRAME \
    /**\
     * pointer to the picture planes.\
     * This might be different from the first allocated byte\
     * - encoding: \
     * - decoding: \
     */\
    uint8_t *data[4];\
    int linesize[4];\
    /**\
     * pointer to the first allocated byte of the picture. Can be used in get_buffer/release_buffer.\
     * This isn't used by libavcodec unless the default get/release_buffer() is used.\
     * - encoding: \
     * - decoding: \
     */\
    uint8_t *base[4];\
    /**\
     * 1 -> keyframe, 0-> not\
     * - encoding: Set by libavcodec.\
     * - decoding: Set by libavcodec.\
     */\
    int key_frame;\
\
    /**\
     * Picture type of the frame, see ?_TYPE below.\
     * - encoding: Set by libavcodec. for coded_picture (and set by user for input).\
     * - decoding: Set by libavcodec.\
     */\
    int pict_type;\
\
    /**\
     * presentation timestamp in time_base units (time when frame should be shown to user)\
     * If AV_NOPTS_VALUE then frame_rate = 1/time_base will be assumed.\
     * - encoding: MUST be set by user.\
     * - decoding: Set by libavcodec.\
     */\
    int64_t pts;\
\
    /**\
     * picture number in bitstream order\
     * - encoding: set by\
     * - decoding: Set by libavcodec.\
     */\
    int coded_picture_number;\
    /**\
     * picture number in display order\
     * - encoding: set by\
     * - decoding: Set by libavcodec.\
     */\
    int display_picture_number;\
\
    /**\
     * quality (between 1 (good) and FF_LAMBDA_MAX (bad)) \
     * - encoding: Set by libavcodec. for coded_picture (and set by user for input).\
     * - decoding: Set by libavcodec.\
     */\
    int quality; \
\
    /**\
     * buffer age (1->was last buffer and dint change, 2->..., ...).\
     * Set to INT_MAX if the buffer has not been used yet.\
     * - encoding: unused\
     * - decoding: MUST be set by get_buffer().\
     */\
    int age;\
\
    /**\
     * is this picture used as reference\
     * - encoding: unused\
     * - decoding: Set by libavcodec. (before get_buffer() call)).\
     */\
    int reference;\
\
    /**\
     * QP table\
     * - encoding: unused\
     * - decoding: Set by libavcodec.\
     */\
    int8_t *qscale_table;\
    /**\
     * QP store stride\
     * - encoding: unused\
     * - decoding: Set by libavcodec.\
     */\
    int qstride;\
\
    /**\
     * mbskip_table[mb]>=1 if MB didn't change\
     * stride= mb_width = (width+15)>>4\
     * - encoding: unused\
     * - decoding: Set by libavcodec.\
     */\
    uint8_t *mbskip_table;\
\
    /**\
     * motion vector table\
     * @code\
     * example:\
     * int mv_sample_log2= 4 - motion_subsample_log2;\
     * int mb_width= (width+15)>>4;\
     * int mv_stride= (mb_width << mv_sample_log2) + 1;\
     * motion_val[direction][x + y*mv_stride][0->mv_x, 1->mv_y];\
     * @endcode\
     * - encoding: Set by user.\
     * - decoding: Set by libavcodec.\
     */\
    int16_t (*motion_val[2])[2];\
\
    /**\
     * macroblock type table\
     * mb_type_base + mb_width + 2\
     * - encoding: Set by user.\
     * - decoding: Set by libavcodec.\
     */\
    uint32_t *mb_type;\
\
    /**\
     * log2 of the size of the block which a single vector in motion_val represents: \
     * (4->16x16, 3->8x8, 2-> 4x4, 1-> 2x2)\
     * - encoding: unused\
     * - decoding: Set by libavcodec.\
     */\
    uint8_t motion_subsample_log2;\
\
    /**\
     * for some private data of the user\
     * - encoding: unused\
     * - decoding: Set by user.\
     */\
    void *opaque;\
\
    /**\
     * error\
     * - encoding: Set by libavcodec. if flags&CODEC_FLAG_PSNR.\
     * - decoding: unused\
     */\
    uint64_t error[4];\
\
    /**\
     * type of the buffer (to keep track of who has to deallocate data[*])\
     * - encoding: Set by the one who allocates it.\
     * - decoding: Set by the one who allocates it.\
     * Note: User allocated (direct rendering) & internal buffers cannot coexist currently.\
     */\
    int type;\
    \
    /**\
     * When decoding, this signals how much the picture must be delayed.\
     * extra_delay = repeat_pict / (2*fps)\
     * - encoding: unused\
     * - decoding: Set by libavcodec.\
     */\
    int repeat_pict;\
    \
    /**\
     * \
     */\
    int qscale_type;\
    \
    /**\
     * The content of the picture is interlaced.\
     * - encoding: Set by user.\
     * - decoding: Set by libavcodec. (default 0)\
     */\
    int interlaced_frame;\
    \
    /**\
     * If the content is interlaced, is top field displayed first.\
     * - encoding: Set by user.\
     * - decoding: Set by libavcodec.\
     */\
    int top_field_first;\
    \
    /**\
     * Pan scan.\
     * - encoding: Set by user.\
     * - decoding: Set by libavcodec.\
     */\
    AVPanScan *pan_scan;\
    \
    /**\
     * Tell user application that palette has changed from previous frame.\
     * - encoding: ??? (no palette-enabled encoder yet)\
     * - decoding: Set by libavcodec. (default 0).\
     */\
    int palette_has_changed;\
    \
    /**\
     * codec suggestion on buffer type if != 0\
     * - encoding: unused\
     * - decoding: Set by libavcodec. (before get_buffer() call)).\
     */\
    int buffer_hints;\
\
    /**\
     * DCT coefficients\
     * - encoding: unused\
     * - decoding: Set by libavcodec.\
     */\
    short *dct_coeff;\
\
    /**\
     * motion referece frame index\
     * - encoding: Set by user.\
     * - decoding: Set by libavcodec.\
     */\
    int8_t *ref_index[2];

#define FF_QSCALE_TYPE_MPEG1 0
#define FF_QSCALE_TYPE_MPEG2 1
#define FF_QSCALE_TYPE_H264  2

#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 somewhere else; don't deallocate image (data/base), all other tables are not shared.
#define FF_BUFFER_TYPE_COPY     8 ///< Just a (modified) copy of some other buffer, don't deallocate 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

/**
 * main external API structure
 */
typedef struct AVCodecContext {
    /**
     * information 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 libavcodec. 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 need additional format info. It is stored here.
     * If any muxer uses this then ALL demuxers/parsers AND encoders for the
     * specific codec MUST set it correctly otherwise stream copy breaks.
     * In general use of this field by muxers is not recommanded.
     * - encoding: Set by libavcodec.
     * - decoding: Set by libavcodec. (FIXME: Is this OK?)
     */
    int sub_id;

    /**
     * Motion estimation algorithm used for video coding.
     * 1 (zero), 2 (full), 3 (log), 4 (phods), 5 (epzs), 6 (x1), 7 (hex),
     * 8 (umh), 9 (iter) [7, 8 are x264 specific, 9 is snow specific]
     * - encoding: MUST be set by user.
     * - decoding: unused
     */
    int me_method;

    /**
     * some codecs need / can use extradata like Huffman tables.
     * mjpeg: Huffman tables
     * rv10: additional flags
     * mpeg4: global headers (they can be in the bitstream or here)
     * The allocated memory should be FF_INPUT_BUFFER_PADDING_SIZE bytes larger
     * than extradata_size to avoid prolems if it is read with the bitstream reader.
     * The bytewise contents of extradata must not depend on the architecture or CPU endianness.
     * - encoding: Set/allocated/freed by libavcodec.
     * - decoding: Set/allocated/freed by user.
     */
    uint8_t *extradata;
    int extradata_size;

    /**
     * This is the fundamental unit of time (in seconds) in terms
     * of which frame timestamps are represented. For fixed-fps content,
     * timebase should be 1/framerate and timestamp increments should be
     * identically 1.
     * - encoding: MUST be set by user.
     * - decoding: Set by libavcodec.
     */
    AVRational time_base;

    /* video only */
    /**
     * picture width / height.
     * - encoding: MUST be set by user.
     * - decoding: Set by libavcodec.
     * Note: For compatibility it is possible to set this instead of
     * coded_width/height before decoding.
     */
    int width, height;

#define FF_ASPECT_EXTENDED 15

    /**
     * the number of pictures in a group of pictures, or 0 for intra_only
     * - encoding: Set by user.
     * - decoding: unused
     */
    int gop_size;

    /**
     * Pixel format, see PIX_FMT_xxx.
     * - encoding: Set by user.
     * - decoding: Set by libavcodec.
     */
    enum PixelFormat pix_fmt;

    /**
     * Frame rate emulation. If not zero, the 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 a horizontal band. It improves cache usage. Not
     * all codecs can do that. You must check the codec capabilities
     * beforehand.
     * - 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 second
    int channels;

    /**
     * audio sample format
     * - encoding: Set by user.
     * - decoding: Set by libavcodec.
     */
    enum SampleFormat sample_fmt;  ///< sample format, currently unused

    /* The following data should not be initialized. */
    /**
     * Samples per packet, initialized when calling 'init'.
     */
    int frame_size;
    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 libavcodec.
     * - decoding: unused