avformat/rtsp: support for listen_timeout option for sdp

Now the listen timeout is hardcoded(10s).
How to test(30s timeout):
./ffprobe  -listen_timeout 30 -protocol_whitelist rtp,udp,file -i test.sdp

Signed-off-by: Limin Wang <lance.lmwang@gmail.com>

libavformat/rtsp.c

@@ -55,7 +55,6 @@
  * and read_packet(), in seconds  */
 #define POLL_TIMEOUT_MS 100
 #define READ_PACKET_TIMEOUT_S 10
-#define MAX_TIMEOUTS READ_PACKET_TIMEOUT_S * 1000 / POLL_TIMEOUT_MS
 #define SDP_MAX_SIZE 16384
 #define RECVBUF_SIZE 10 * RTP_MAX_PACKET_LENGTH
 #define DEFAULT_REORDERING_DELAY 100000
@@ -115,6 +114,7 @@ static const AVOption sdp_options[] = {
     RTSP_FLAG_OPTS("sdp_flags", "SDP flags"),
     { "custom_io", "use custom I/O", 0, AV_OPT_TYPE_CONST, {.i64 = RTSP_FLAG_CUSTOM_IO}, 0, 0, DEC, "rtsp_flags" },
     { "rtcp_to_source", "send RTCP packets to the source address of received packets", 0, AV_OPT_TYPE_CONST, {.i64 = RTSP_FLAG_RTCP_TO_SOURCE}, 0, 0, DEC, "rtsp_flags" },
+    { "listen_timeout", "set maximum timeout (in seconds) to wait for incoming connections", OFFSET(initial_timeout), AV_OPT_TYPE_INT, {.i64 = READ_PACKET_TIMEOUT_S}, INT_MIN, INT_MAX, DEC },
     RTSP_MEDIATYPE_OPTS("allowed_media_types", "set media types to accept from the server"),
     COMMON_OPTS(),
     { NULL },
@@ -122,6 +122,8 @@ static const AVOption sdp_options[] = {
 
 static const AVOption rtp_options[] = {
     RTSP_FLAG_OPTS("rtp_flags", "set RTP flags"),
+    { "listen_timeout", "set maximum timeout (in seconds) to wait for incoming connections", OFFSET(initial_timeout), AV_OPT_TYPE_INT, {.i64 = READ_PACKET_TIMEOUT_S}, INT_MIN, INT_MAX, DEC },
+    RTSP_MEDIATYPE_OPTS("allowed_media_types", "set media types to accept from the server"),
     COMMON_OPTS(),
     { NULL },
 };
@@ -1985,9 +1987,10 @@ static int udp_read_packet(AVFormatContext *s, RTSPStream **prtsp_st,
 {
     RTSPState *rt = s->priv_data;
     RTSPStream *rtsp_st;
-    int n, i, ret, timeout_cnt = 0;
+    int n, i, ret;
     struct pollfd *p = rt->p;
     int *fds = NULL, fdsnum, fdsidx;
+    int runs = rt->initial_timeout * 1000LL / POLL_TIMEOUT_MS;
 
     if (!p) {
         p = rt->p = av_malloc_array(2 * rt->nb_rtsp_streams + 1, sizeof(struct pollfd));
@@ -2028,7 +2031,6 @@ static int udp_read_packet(AVFormatContext *s, RTSPStream **prtsp_st,
         n = poll(p, rt->max_p, POLL_TIMEOUT_MS);
         if (n > 0) {
             int j = rt->rtsp_hd ? 1 : 0;
-            timeout_cnt = 0;
             for (i = 0; i < rt->nb_rtsp_streams; i++) {
                 rtsp_st = rt->rtsp_streams[i];
                 if (rtsp_st->rtp_handle) {
@@ -2049,7 +2051,7 @@ static int udp_read_packet(AVFormatContext *s, RTSPStream **prtsp_st,
                 }
             }
 #endif
-        } else if (n == 0 && ++timeout_cnt >= MAX_TIMEOUTS) {
+        } else if (n == 0 && --runs <= 0) {
             return AVERROR(ETIMEDOUT);
         } else if (n < 0 && errno != EINTR)
             return AVERROR(errno);