Auto MPG ?

Continuing on my quest to upload files from the HDR T2, I've converted a couple of files to MPG, they are indeed a fair degree smaller. Would it be a big deal I wonder to create a script that could be run under cron to do this in a similar way to 'unencrypt'? While on the subject of unencrypt, is the CPU usage still an issue and is this the same for decrypt via webif?