Why isn't Wirecast 64 bit yet?
In 2003 64-bit CPUs were introduced to the (previously 32-bit) mainstream personal computer arena in the form of the x86-64 and 64-bit PowerPC processor architectures and in 2012.

A 64-bit register can store 264 (over 18 quintillion or 1.8×1019) different values. Hence, a processor with 64-bit memory addresses can directly access 264 bytes (=16 exbibytes) of byte-addressable memory.
(http://en.wikipedia.org/wiki/64-bit_computing)