You should be seeing dual core 2.5GHz ARM cellphones by the end of the year that can encode/decode 1080P. I think it can edit as well.
I would not think so, since TI has the Cortex A9 on the OMAP4440 pushed quite near it's limits at a little over 1GHz dual core I would bet my right "ARM" that they won't push a new Cortex over 2GHz this year. Ill take that "RISC".
