Video Freeze on QuickTime

I have an 2009 (I know, a dinosaur) iMac, running on El Capitan 10.11.6. I'm trying to play a video from a USB Flash drive, which is a rather huge 200+ GB file. It opens by default to QuickTime (version 10), plays for a few moments, then audio goes out, it slows, freezes, goes out of sync, and basically stops playing. If a restart it, it does the same thing: plays OK for a few moments, then the audio goes out, it slows down, and freezes. Is there anything I can do to get it to play (use or install a different player?), or is my computer too old with too little space to handle such a big file on the flash drive? Thanks for any help.