Why does Movies take up 312 GB of my 750 GB of storage when I only have one movie stored

My MacBook Pro (Retina, mid 2012) has 750 GB storage, 16 GB Memory, runs OS 10.11.6, processor 2.7 GHz, Intel Core i7. Movies and Other in storage take up 565 GB of my 750 GB storage, however, I only have One (1) movie on my computer. My Apps use 79 GB, Photos use 34 GB, Audio uses 33 GB, and Backups uses 4 GB. Why do the Movies and Other take up so much of the storage and how can I fix the imbalance? How do I fix?