I made an upload tool that needed to handle very large files, and I used WebSockets to do it.

The strategy I used was to parse the MOV/MP4 locally, consider between 2-60 frames of data, hash it, then stream up the hashes to the server. Any hash the server didn't have got a reply to push those bytes.

The two-way nature of this dialog made WebSockets a good fit, although it certainly could have been emulated using other methods, it would have been much more code.