OT: high-definition video and 4gb of ram

hello,

my current system has 2gb ram.  it works great.

is it really necessary to have 4gb of ram for simple hi-def video projects?

i'm not talking about 90 minute movies.  just simple little things, but filmed in hi-def
with a camcorder.

i don't mean "preferable"... i mean "necessary", as in "your computer will lock up
within 10 seconds of trying to do hi-def video on anything less than 4gb of ram."