It seems that you do not need nor want continuous backups and there will never any need to roll back to the previous hour, then do what everybody else does around here — before their world blows up, their laptop is damaged, a command or tool goes awry, there's a disk error underneath your movies, or some new Adobe patch decides to delete something — and run with the occasional and manual backup.
Otherwise, Time Machine will do this and will "borrow" that used storage to keep extra backups — releasing it when your own usage increases — if it can't connect to the TM targets.
Put another way, OS X is using what you aren't — and will transparently release that storage usage back to you if and when you need it — in order to provide you with a benefit.
This is a variation of the system physical memory usage discussion, where somebody sees OS X caching user and disk data in memory and then acquires one of those add-on tools that goes and argues with OS X about this caching, in an effort to have visible free memory — free memory is inherently wasted memory — and which generally means the user is now hitting your disk rather than using some otherwise unoccupied memory to try to reduce the disk I/O and improve your performance.
But to answer your question, you can choose to effectively waste that storage that you're not using. Turn off TM either in general or on the specified device, or for the specified movies, wipe the disk and reload its contents from your (other) backup of your files, and you won't have any background use.