VMR versus Overlay mixer

[vlada]

Hi, could somebody explain me what is the difference between these two mixers. Is there a possibility to use VMR with "theatre mode" of ATI and Maxtor cards? If I use VMR instead of overlay, the video is not displayed in fullscreen on my TV. It only works with overlay. Thanks, Vlada

[ultimatebilly]

Overlay is a hardware-feature of your graphic card, which doesn't put much load on your CPU, because the GPU is doing most of the work.
VMR (Video Mixer Renderer) is a software overlay, which is generated by your CPU...
It seems that your card doesn't support using VMR for TV fullscreen-playback, because it's a feature of your card which uses it's GPU, and which was specifically designed for that task (whereas the graphic card may not be able to provide this feature for applications using software rendering).
I hope was I said is correct, I don't have much knowledge about this myself, that's only what I heard...
Overlay works with some kind of chroma-keying mechanism, it put's a layer of colour (green?) over the picture and put's the video on it by making the overlay invisible - but as you can see I don't really understand/know how this work...

I hope this was of any help!