In version 0.10.20 gstpoll has a new, windows specific, gstpoll implementation instead of relying on winsock's select(). rtsp does not work any more with this and times out in the rtsp code (waiting for the socket to be ready for writing).

I've instrumented the gstpoll code to show the API called by the rtsp/rtcp/udp code and I attach this log as first comment.

I've somehow managed to "fix" the problem by calling gst_poll_fd_ignored() before actually writing in the rtsp socket but it's clearly not the intended use of the function. The patch "solving" the problem is attached as second comment

To reproduce the issue, you can setup a rtsp server with vlc for instance:
$ vlc --ttl 10 -vvv -I  telnet --telnet-password gst --rtsp-host 0.0.0.0:5554
$ telnet 127.0.0.1 4212 (passord gst)
> new test vod enabled
> setup test input /home/damien/samples/xxxxxxxx.mpeg

gst-launch-0.10.exe  --gst-debug-no-color --gst-plugin-path=c:\xxxxxxxx\lib\gstreamer-0.10 rtspsrc location="rtsp://10.250.154.29:5554/test" ! decodebin ! ffmpegcolorspace ! directdrawsink

I think it would be usefull to Cc. Ole André but I don't want to be gross, so let's hope he'll discover this bug report quickly :p