Seems to me that for frequency modulation to work, the carrier frequency must be many times the data speed. A few cycles at any one frequency are required to establish a datum. This is the case for binary or analog transmitting. It's how audio frequencies can be broadcast by FM.
We cannot try to make the data rate so fast that it allows time for only one or two cycles of the FM carrier. A datum could not be recognized in that event. I'm not sure but I would imagine video (or HD video) gets into this realm.
---------- Post added at 06:10 ---------- Previous post was at 05:35 ----------
Now that I remember that my computer can receive HD Youtube videos over wifi. 2.4 GHz....
However that isn't full-screen tv quality.
So it would appear it becomes a question how large the frame size is, and how fast the frame rate is.