rtsp: Send mode=record instead of mode=receive

This seems to be the correct mode to send, according to the
original RTSP RFC, and matches the method RECORD which is
sent later when starting to send data.

Darwin Streaming Server works fine with either of them.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/rtsp.c

@@ -1284,7 +1284,7 @@ int ff_rtsp_make_setup_request(AVFormatContext *s, const char *host, int port,
                      "%s/UDP;multicast", trans_pref);
         }
         if (s->oformat) {
-            av_strlcat(transport, ";mode=receive", sizeof(transport));
+            av_strlcat(transport, ";mode=record", sizeof(transport));
         } else if (rt->server_type == RTSP_SERVER_REAL ||
                    rt->server_type == RTSP_SERVER_WMS)
             av_strlcat(transport, ";mode=play", sizeof(transport));