Source: https://github.com/brianhvo02/libmpv-wasm

Works (to a degree) in Chromium, but not in Firefox. The reason is that the API to give access to a whole folder to a website is missing in Firefox.

An attempt to play a DVD rip ended up with error messages in the browser console about unaligned access. Playing one of the individual VOBs succeeded, consuming approximately one CPU core.

The usual "d" shortcut to enable deinterlacing is not supported, though.