mplayer multicast start up behavior

Apologies for the previous thread hijack and top post.

I'm trying to use mplayer to receive multicast audio, I ran into a
problem where mplayer won't start unless the multicast is already
streaming. ffplay does not have this problem.

See
https://superuser.com/questions/307130/ffmpeg-command-to-stream-video-to-a-multicast-address

If you try to start mplayer before the stream is there, it will fail
with:

Timeout! No data from host 239.1.2.3
udp_streaming_start failed
No stream found to handle url udp://239.1.2.3:4567

Is there a way to make mplayer start without the stream already being
present?

--
Michael A Hawkins
Stamford, CT 06902 USA