url_split(NULL, 0, hostname, sizeof(hostname), &port, NULL, 0, uri);
url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &port, NULL, 0, uri);
int udp_set_remote_url(URLContext *h, const char *uri){    UDPContext *s = h->priv_data;    char hostname[256];    int port;        url_split(NULL, 0, hostname, sizeof(hostname), &port, NULL, 0, uri);    /* set the destination address */    if (resolve_host(&s->dest_addr.sin_addr, hostname) < 0)        return AVERROR_IO;    s->dest_addr.sin_family = AF_INET;    s->dest_addr.sin_port = htons(port);    return 0;}