Its a converter and a codec(intermediate) for editing, AVCHD is very processor intensive, and the intermediate codec releaves processor load and interpolates the 4.2.0 8bit video to 4.2.2 10bit video, it gives you a better color space to work in, the files are about twice the size, but no problem with Sata II drives, there are other NLEs that use other methods, like GV/Canopus’s HQ codec, it accomplishes the same thing but is proprietary to Edius.