ffmpeg——rtsp

void av_url_split(char *proto, int proto_size,
                  char *authorization, int authorization_size,
                  char *hostname, int hostname_size,
                  int *port_ptr,
                  char *path, int path_size,
                  const char *url)
{//{协议}：//{用户名}:{密码}@{主机名}:{端口号}/{路径}/{文件}?{参数}
    /* parse protocol *///1.解析出协议，如http://，放入proto
    if ((p = strchr(url, ':'))) {
        av_strlcpy(proto, url, FFMIN(proto_size, p + 1 - url));
        p++; /* skip ':' */
        if (*p == '/') p++;
        if (*p == '/') p++;
    } else {
        /* no protocol means plain filename */
        av_strlcpy(path, url, path_size);
        return;
    }

    /* separate path from hostname */
    ls = strchr(p, '/');
    ls2 = strchr(p, '?');
    if(!ls)
        ls = ls2;
    else if (ls && ls2)
        ls = FFMIN(ls, ls2);
    if(ls)
        av_strlcpy(path, ls, path_size); //2.得到路径，放入path中
    else
        ls = &p[strlen(p)]; // XXX

    /* the rest is hostname, use that to parse auth/port */
    if (ls != p) {
        /* authorization (user[:pass]@hostname) */
        if ((at = strchr(p, '@')) && at < ls) {
            av_strlcpy(authorization, p,
                       FFMIN(authorization_size, at + 1 - p));  //3.得到{用户名}:{密码}，放入authorization中
            p = at + 1; /* skip '@' */
        }

        if (*p == '[' && (brk = strchr(p, ']')) && brk < ls) {
            /* [host]:port */
            av_strlcpy(hostname, p + 1,
                       FFMIN(hostname_size, brk - p));  //4.得到主机名，放入hostname中
            if (brk[1] == ':' && port_ptr)
                *port_ptr = atoi(brk + 2);   //5.得到端口号，放入port_ptr中
        } else if ((col = strchr(p, ':')) && col < ls) {
            av_strlcpy(hostname, p,
                       FFMIN(col + 1 - p, hostname_size));
            if (port_ptr) *port_ptr = atoi(col + 1);
        } else
            av_strlcpy(hostname, p,
                       FFMIN(ls + 1 - p, hostname_size));
    }
}