tl:dr; mp4, gateway.
Discussion
testing
https://gateway.ipfs.io/ipfs/QmaoF4cKdQRu9T6JMVGqZT82gRkWQyh5LeNBdji3rZRbsm?filename=beanie.mp4
i suck
looks like they were using the cloudflare gateway and direct link to the mp4 without the ?filename=xxx you're using here.
That didn't work either.. Some files are breaking due to CORS errors. I suspect this isn't working because it's missing the extension