avcodec.h

手机端的H264源码

    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;\
\
	/**\
     * 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;\
    \
	/**\
     * 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;\
    \

#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

/**
 * main external api structure.
 */
typedef struct AVCodecContext {
    /**
     * 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;

    /**
     * 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;

    /**
     * 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

    /**
     * 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;    

    /* 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 
    
    /**
     * 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;    
    
    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;        
        
    /**
     * called at the beginning of each frame to get a buffer for it.
     * if pic.reference is set then the frame will be read later by lavc
     * width and height should be rounded up to the next multiple of 16
     * - encoding: unused
     * - decoding: set by lavc, user can override
     */
    int (*get_buffer)(struct AVCodecContext *c, AVFrame *pic);
    
    /**
     * called to release buffers which where allocated with get_buffer.
     * a released buffer can be reused in get_buffer()
     * pic.data[*] must be set to NULL
     * - encoding: unused
     * - decoding: set by lavc, user can override
     */
    void (*release_buffer)(struct AVCodecContext *c, AVFrame *pic);

    /**
     * is 1 if the decoded stream contains b frames, 0 otherwise.
     * - encoding: unused
     * - decoding: set by lavc
     */
    int has_b_frames;    
    
#define FF_DCT_AUTO    0
#define FF_DCT_FASTINT 1
#define FF_DCT_INT     2
#define FF_DCT_MMX     3
#define FF_DCT_MLIB    4
#define FF_DCT_ALTIVEC 5
#define FF_DCT_FAAN    6
    
    /**
     * idct algorithm, see FF_IDCT_* below.
     * - encoding: set by user
     * - decoding: set by user
     */
    int idct_algo;
#define FF_IDCT_AUTO         0
#define FF_IDCT_INT          1
#define FF_IDCT_SIMPLE       2
#define FF_IDCT_SIMPLEMMX    3
#define FF_IDCT_LIBMPEG2MMX  4
#define FF_IDCT_PS2          5
#define FF_IDCT_MLIB         6
#define FF_IDCT_ARM          7
#define FF_IDCT_ALTIVEC      8
#define FF_IDCT_SH4          9
#define FF_IDCT_SIMPLEARM    10


#define FF_EC_GUESS_MVS   1
#define FF_EC_DEBLOCK     2

    /**
     * dsp_mask could be add used to disable unwanted CPU features
     * CPU features (i.e. MMX, SSE. ...)
     *
     * with FORCE flag you may instead enable given CPU features
     * (Dangerous: usable in case of misdetection, improper usage however will
     * result into program crash)
     */
    unsigned dsp_mask;

    /**
     * bits per sample/pixel from the demuxer (needed for huffyuv).
     * - encoding: set by lavc
     * - decoding: set by user
     */
     int bits_per_sample;
    
    /**
     * the picture in the bitstream.
     * - encoding: set by lavc
     * - decoding: set by lavc
     */
    AVFrame *coded_frame;
    
#define FF_CMP_SAD  0
#define FF_CMP_SSE  1
#define FF_CMP_SATD 2
#define FF_CMP_DCT  3
#define FF_CMP_PSNR 4
#define FF_CMP_BIT  5
#define FF_CMP_RD   6
#define FF_CMP_ZERO 7
#define FF_CMP_VSAD 8
#define FF_CMP_VSSE 9
#define FF_CMP_CHROMA 256
        
    /**
     * internal_buffer count. 
     * Dont touch, used by lavc default_get_buffer()
     */
    int internal_buffer_count;
    
    /**
     * internal_buffers. 
     * Dont touch, used by lavc default_get_buffer()
     */
    void *internal_buffer;
    
    /**
     * CODEC_FLAG2_*.
     * - encoding: set by user.
     * - decoding: set by user.
     */
    int flags2;

    /**
     * Thread count.
     * is used to decide how many independant tasks should be passed to execute()
     * - encoding: set by user
     * - decoding: set by user
     */
    int thread_count;
    
} AVCodecContext;

/**
 * AVCodec.
 */
typedef struct AVCodec {
    const char *name;
    enum CodecType type;
    int id;
    int priv_data_size;
    int (*init)(AVCodecContext *);
    int (*encode)(AVCodecContext *, uint8_t *buf, int buf_size, void *data);
    int (*close)(AVCodecContext *);
    int (*decode)(AVCodecContext *, void *outdata, int *outdata_size,
                  uint8_t *buf, int buf_size);

    struct AVCodec *next;
    void (*flush)(AVCodecContext *);    
} AVCodec;


extern AVCodec h264_decoder;

extern AVCodec *first_avcodec;

/* returns LIBAVCODEC_VERSION_INT constant */
unsigned avcodec_version(void);
/* returns LIBAVCODEC_BUILD constant */
unsigned avcodec_build(void);
void avcodec_init(void);

void register_avcodec(AVCodec *format);
AVCodec *avcodec_find_encoder(enum CodecID id);
AVCodec *avcodec_find_encoder_by_name(const char *name);
AVCodec *avcodec_find_decoder(enum CodecID id);
AVCodec *avcodec_find_decoder_by_name(const char *name);

void avcodec_get_context_defaults(AVCodecContext *s);
AVCodecContext *avcodec_alloc_context(void);
void avcodec_get_frame_defaults(AVFrame *pic);
AVFrame *avcodec_alloc_frame(void);

int avcodec_default_get_buffer(AVCodecContext *s, AVFrame *pic);
void avcodec_default_release_buffer(AVCodecContext *s, AVFrame *pic);
void avcodec_default_free_buffers(AVCodecContext *s);

int avcodec_thread_init(AVCodecContext *s, int thread_count);
void avcodec_thread_free(AVCodecContext *s);
int avcodec_thread_execute(AVCodecContext *s, int (*func)(AVCodecContext *c2, void *arg2),void **arg, int *ret, int count);
//FIXME func typedef

/**
 * opens / inits the AVCodecContext.
 * not thread save!
 */
int avcodec_open(AVCodecContext *avctx, AVCodec *codec);

int avcodec_decode_video(AVCodecContext *avctx, AVFrame *picture, 
                         int *got_picture_ptr,
                         uint8_t *buf, int buf_size);
int avcodec_parse_frame(AVCodecContext *avctx, uint8_t **pdata, 
                        int *data_size_ptr,
                        uint8_t *buf, int buf_size);

int avcodec_close(AVCodecContext *avctx);

void avcodec_register_all(void);

void avcodec_flush_buffers(AVCodecContext *avctx);

/* misc usefull functions */

/**
 * returns a single letter to describe the picture type
 */
char av_get_pict_type_char(int pict_type);


/* memory */
void *av_malloc(unsigned int size);
void *av_mallocz(unsigned int size);
void *av_realloc(void *ptr, unsigned int size);
void av_free(void *ptr);
char *av_strdup(const char *s);
void av_freep(void *ptr);
void *av_fast_realloc(void *ptr, unsigned int *size, unsigned int min_size);
/* for static data only */
/* call av_free_static to release all staticaly allocated tables */
void av_free_static(void);
void *av_mallocz_static(unsigned int size);

#ifdef __cplusplus
}
#endif

#endif /* AVCODEC_H */