[MPlayer-dev-eng] mplayer UDP port number

[bertolaz]

Hi,
I'm a master student and for my thesis I have to manage the QoS of a 
multimedia streamig service. My application reserve an amount of bandwtidth 
for an rtsp session and  needs to know in advance on which port the player 
will receive the flow.  
I'd like to know if it's possible to set the host UDP port number for an 
incoming flow in the command line.  Is there a way to tell mplayer which port

to use?
I've read mplayer documentation but it seems to me that it's possible only to

specify the server port number, is it right?
can anyone help me? 
thanks 
Rosa