I moved on from that a decade ago but it was a neat project at the time.
But I deployed my first integration of WASM about a month ago for PaperlessPost.com. It is a custom h264 video decoder that renders into a canvas that manages timing relative to other graphics layers over this video. This code works around a series of bugs we've found with the built in video player. It went smoothly enough that we are looking into a few other hot spots in our code that could also be improved with WASM.
One avenue for WASM might be simply polyfilling the features that are not consistently implemented across browsers.
Ten years ago I did the same but in Java and JOGL (before Apple banned OpenGL graphics within Java Applets embedded within a webpage). Was used for AR Watch try on within https://www.watchwarehouse.com and Ebay. The pain of Flash and Applets still wake me up at night.
I'm also building something very similar but with the ability for custom codecs (https://www.v-nova.com/ is very good). Probably the same issues too! Could I know more about your solution?