[MPlayer-users] change_rectangle in slave mode doesn't do anything

[Steve Ricketts]

I'm using mplayer in slave mode and trying to change the width/height and x/y
location.  No matter what I enter, nothing happens.  

change_rectangle 0 100 (increase width by 100)
change_rectangle 1 -200 (decrease height by 100)
change_rectangle 2 -1 (move to leftmost pos)

Can anyone tell me what I need to do for the ability to resize and reposition a
video under slave mode?