Animated Backgrounds with `mplayer -rootwin` in Openbox?

I've decided to try adding an animated background to my Gentoo install, which is using Xorg and Openbox. I run the command mplayer <video file> -rootwin and it starts playing the video on the desktop just as I expect.

Now for the problem. My programs that have transparent backgrounds (ternimal, panels, etc) do not show the video file in the background, it simply comtinues showing whatever the background was prior to running mplayer. Using mplayer2 did not help. I think it may be related to these errors from both mplayer and mplayer2, but I can't find anything about them:

X11 error: BadAccess during XSelectInput Call
X11 error: The 'ButtonPressMask' mask of specified window was probably already used by another application (see man XSelectInput)
X11 error: MPlayer discards mouse control (reconfiguring)

Also, this may be relevant, so here are my USE flags for mplayer:

X a52 cdio dts dvb dvd dvdnav enca encode gif iconv jpeg libass mad mng mp3 network opengl osdmenu png pulseaudio sdl shm truetype unicode v4l vorbis x264 xscreensaver xv xvid
-aalib -alsa (-altivec) (-aqua) -bidi -bindist -bl -bluray -bs2b -cddb -cdparanoia -cpudetection -debug -dga -directfb -doc -dv -faac -faad -fbcon -ftp -ggi -gsm -ipv6 -jack -joystick -jpeg2k -ladspa -libcaca -libmpeg2 -lirc -live -lzo -md5sum -nas -nut -openal -oss -pnm -pvr -radio -rar -rtc -rtmp -samba (-selinux) -speex -tga -theora -toolame -tremor -twolame -vdpau (-vidix) -xanim -xinerama -xvmc -zoran