SDL Surface as mplayer output


I’ve a small SDL application and I’d like to use a second surface as
output “window” for mplayer (inside this application even).
But as far as I know, just the top SDL window has window id, or?
So it won’t be possible use the -wid option of mplayer.

Is there any other way to use a surface (for example a 100x100
rectangle) as mplayeroutput?