HD-SDI another methord?

I am not sure about that particular chip, but most common are National (now TI) chips. Check here. (http://www.national.com/analog/interface/sdi)

You can use deserializer, however remember the speed, You'll have to work with... If it deserializes to 10bit bus, which is then 1485/10=148.5MHz clock - it is possible, but if You use speed more than 300MHz, it could be a tough task.

Using Cyclone IV, which is smaller than EP4CGX30 (or EP4CGX40, can't remember exactly) it's impossible to use HD-SDI, even the transceivers are capable of doing such speed. Probably thats Altera market trick, to move You to the larger devices.

Check the SDI User Guide, everything is written there - what devices support particular standard.