/** * Open an input stream and read the header. The codecs are not opened. * The stream must be closed with avformat_close_input(). * * @param ps Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context). *           May be a pointer to NULL, in which case an AVFormatContext is allocated by this *           function and written into ps. *           Note that a user-supplied AVFormatContext will be freed on failure. * @param url URL of the stream to open. * @param fmt If non-NULL, this parameter forces a specific input format. *            Otherwise the format is autodetected. * @param options  A dictionary filled with AVFormatContext and demuxer-private options. *                 On return this parameter will be destroyed and replaced with a dict containing *                 options that were not found. May be NULL. * * @return 0 on success, a negative AVERROR on failure. * * @note If you want to use custom IO, preallocate the format context and set its pb field. */

int avformat_open_input(AVFormatContext **ps,  const char *filename,  AVInputFormat *fmt,  AVDictionary **options)

typedef struct URLProtocol {const char *name;int (*url_open)(URLContext *h, const char *url, int flags);int (*url_read)(URLContext *h, unsigned char *buf, int size);int (*url_write)(URLContext *h, const unsigned char *buf, int size);int64_t (*url_seek)(URLContext *h, int64_t pos, int whence);int (*url_close)(URLContext *h);struct URLProtocol *next;int (*url_read_pause)(URLContext *h, int pause);int64_t (*url_read_seek)(URLContext *h, int stream_index,int64_t timestamp, int flags);int (*url_get_file_handle)(URLContext *h);int priv_data_size;const AVClass *priv_data_class;int flags;int (*url_check)(URLContext *h, int mask);
} URLProtocol;

URLProtocol ff_pipe_protocol = {.name                = "pipe",.url_open            = pipe_open,.url_read            = file_read,.url_write           = file_write,.url_get_file_handle = file_get_handle,.url_check           = file_check,
};

URLProtocol ff_rtmp_protocol = {.name                = "rtmp",.url_open            = rtmp_open,.url_read            = rtmp_read,.url_write           = rtmp_write,.url_close           = rtmp_close,.url_read_pause      = rtmp_read_pause,.url_read_seek       = rtmp_read_seek,.url_get_file_handle = rtmp_get_file_handle,.priv_data_size      = sizeof(RTMP),.flags               = URL_PROTOCOL_FLAG_NETWORK,
};