HiDef (short for high definition), also called 24p, is a 24 frames-per-second digital video format for high-resolution capture of motion pictures.
[1] As of 2003, there are two 24p HD formats: Sony 24p and Panasonic 24p.
Notably, they were used by George Lucas for the production of his second Star Wars prequel, Attack of the Clones.
The advantage of shooting with digital-capture cameras is the efficiency in the production process.
Also, if it is projected with a digital projector, no transference to film is required, either.