Indeed, in fact if using YUV & overlay/textured, 720p should be within the bandwidth limitations (other possible bottlenecks aside eg decoding).
Thanks for the detailed answers, and sorry yto the OP for the thread detour 
It might be pushing it for a SAM460, which is why I'd really like to see a hardware decoder.
These are often incorporated into ARM Socs (seperate from the GPU), but we could add one via PCI or PCI-e.
And yes, sorry for the detour.
I myself am a rapib MorphOS user, but that doesn't mean I don't want a Sam460 or X1000. And, as OS4 is the closest OS to MorphOS, obviousaly I keep track of developments in it.