How can I find the other 180G of movies that is taking up memory

So I feel a little dumb asking this, but I've had my Macbook for a few years now and haven't had this problem yet. I recently started filming and creating movies on my Macbook and now iMovie is telling me there is no memory left. I have a 500G hard drive and I've checked the storage to see what was taking up so much space. Turned out that I have 340G of movies on my hard drive. The problem is, I have found all of the videos I have filmed and edited and the total size of all of those files is around 160G. So my question is, where are the other 180G of movies? I have my iPhone backed up to my MacBook and it does sync my videos from my phone (but I cant believe that I've filmed 180G of movies with my phone) to Photos. How can I find these movies? I've tried looking through finder and have failed to locate them, and I do know that Photos is totally separate from that (from what I understand). Any help would be greatly appreciated as I'm curently coping all my filmed movies over to an old iPod to try and ffee up what little room I can.