FFMPEG之结构体解析 --- AVCodec

/*** AVCodec.*/
typedef struct AVCodec {/*** Name of the codec implementation.* The name is globally unique among encoders and among decoders (but an* encoder and a decoder can share the same name).* This is the primary way to find a codec from the user perspective.*/const char *name;/*** Descriptive name for the codec, meant to be more human readable than name.* You should use the NULL_IF_CONFIG_SMALL() macro to define it.*/const char *long_name;enum AVMediaType type;enum AVCodecID id;/*** Codec capabilities.* see AV_CODEC_CAP_**/int capabilities;const AVRational *supported_framerates; ///< array of supported framerates, or NULL if any, array is terminated by {0,0}const enum AVPixelFormat *pix_fmts;     ///< array of supported pixel formats, or NULL if unknown, array is terminated by -1const int *supported_samplerates;       ///< array of supported audio samplerates, or NULL if unknown, array is terminated by 0const enum AVSampleFormat *sample_fmts; ///< array of supported sample formats, or NULL if unknown, array is terminated by -1const uint64_t *channel_layouts;         ///< array of support channel layouts, or NULL if unknown. array is terminated by 0uint8_t max_lowres;                     ///< maximum value for lowres supported by the decoderconst AVClass *priv_class;              ///< AVClass for the private contextconst AVProfile *profiles;              ///< array of recognized profiles, or NULL if unknown, array is terminated by {FF_PROFILE_UNKNOWN}/****************************************************************** No fields below this line are part of the public API. They* may not be used outside of libavcodec and can be changed and* removed at will.* New public fields should be added right above.******************************************************************/int priv_data_size;struct AVCodec *next;/*** @name Frame-level threading support functions* @{*//*** If defined, called on thread contexts when they are created.* If the codec allocates writable tables in init(), re-allocate them here.* priv_data will be set to a copy of the original.*/int (*init_thread_copy)(AVCodecContext *);/*** Copy necessary context variables from a previous thread context to the current one.* If not defined, the next thread will start automatically; otherwise, the codec* must call ff_thread_finish_setup().** dst and src will (rarely) point to the same context, in which case memcpy should be skipped.*/int (*update_thread_context)(AVCodecContext *dst, const AVCodecContext *src);/** @} *//*** Private codec-specific defaults.*/const AVCodecDefault *defaults;/*** Initialize codec static data, called from avcodec_register().*/void (*init_static_data)(struct AVCodec *codec);int (*init)(AVCodecContext *);int (*encode_sub)(AVCodecContext *, uint8_t *buf, int buf_size,const struct AVSubtitle *sub);/*** Encode data to an AVPacket.** @param      avctx          codec context* @param      avpkt          output AVPacket (may contain a user-provided buffer)* @param[in]  frame          AVFrame containing the raw data to be encoded* @param[out] got_packet_ptr encoder sets to 0 or 1 to indicate that a*                            non-empty packet was returned in avpkt.* @return 0 on success, negative error code on failure*/int (*encode2)(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame,int *got_packet_ptr);int (*decode)(AVCodecContext *, void *outdata, int *outdata_size, AVPacket *avpkt);int (*close)(AVCodecContext *);/*** Decode/encode API with decoupled packet/frame dataflow. The API is the* same as the avcodec_ prefixed APIs (avcodec_send_frame() etc.), except* that:* - never called if the codec is closed or the wrong type,* - AVPacket parameter change side data is applied right before calling*   AVCodec->send_packet,* - if AV_CODEC_CAP_DELAY is not set, drain packets or frames are never sent,* - only one drain packet is ever passed down (until the next flush()),* - a drain AVPacket is always NULL (no need to check for avpkt->size).*/int (*send_frame)(AVCodecContext *avctx, const AVFrame *frame);int (*send_packet)(AVCodecContext *avctx, const AVPacket *avpkt);int (*receive_frame)(AVCodecContext *avctx, AVFrame *frame);int (*receive_packet)(AVCodecContext *avctx, AVPacket *avpkt);/*** Flush buffers.* Will be called when seeking*/void (*flush)(AVCodecContext *);/*** Internal codec capabilities.* See FF_CODEC_CAP_* in internal.h*/int caps_internal;
} AVCodec;