Comment 6 for bug 531692

I looked about your hardware, it seems like your card (4500MHD) has a full set of the hardware acceleration:
http://en.wikipedia.org/wiki/Intel_GMA#GMA_X4500
VA-API claims to the support of the G45 chipset:
http://www.freedesktop.org/wiki/Software/vaapi
You may try to rely on the Wikipedia info about your video card. It may be the variations of the chipsets (GL40 GS40 GM45 GS45) virtually the same that G45 is, but I don't exactly know it.
Anyway, try to install va-api library and patched mplayer-vaapi.
More info about mplayer-vaapi you can find here:
http://www.splitted-desktop.com/~gbeauchesne/mplayer-vaapi/