[fun_]

they all callup swrenderer so yes all player that use the default framework can benefit from the Hardware Overlay like the default Google Player does
Though for some reason Archos doesn't want to

I see. thank you.

Imho i find the idea of rendering the Video on a OpenGL surface silly for the GUI ok but for the Video hmm it's just overhead and if you don't want to manipulate the video layer why doing it ?

well, you asked this part to me? I'm not XBMC developer...

I think why using OpenGL is because it can get benefit from 3D GPU. 3D GPU will do necessary work to show decoded raw frames such as color space conversion, scaling, etc.
and this XBMC libstagefright aim to offer hardware decoding function to several devices by general way, i.e. libstagefright + OpenGL.

using hardware specific function such as RK's color space converter, hardware overlay, and deinterlacer should be done in "XBMC for rockchip" as koying mentioned.

I guess using hardware composer (hwc) framework in Android may be better, it will use best hardware for composing on each device. but I'm not video app developer, I'm not sure hwc can be used for video streams from native code without overhead.