rtsp: Move the pollfd setup out of the for loop

libavformat/rtsp.c

@@ -1920,12 +1920,6 @@ static int udp_read_packet(AVFormatContext *s, RTSPStream **prtsp_st,
     struct pollfd *p = rt->p;
     int *fds = NULL, fdsnum, fdsidx;
 
-    for (;;) {
-        if (ff_check_interrupt(&s->interrupt_callback))
-            return AVERROR_EXIT;
-        if (wait_end && wait_end - av_gettime_relative() < 0)
-            return AVERROR(EAGAIN);
-        max_p = 0;
     if (rt->rtsp_hd) {
         tcp_fd = ffurl_get_file_handle(rt->rtsp_hd);
         p[max_p].fd = tcp_fd;
@@ -1953,6 +1947,12 @@ static int udp_read_packet(AVFormatContext *s, RTSPStream **prtsp_st,
             av_free(fds);
         }
     }
+
+    for (;;) {
+        if (ff_check_interrupt(&s->interrupt_callback))
+            return AVERROR_EXIT;
+        if (wait_end && wait_end - av_gettime_relative() < 0)
+            return AVERROR(EAGAIN);
         n = poll(p, max_p, POLL_TIMEOUT_MS);
         if (n > 0) {
             int j = 1 - (tcp_fd == -1);