Visualizing binary files with ImHex's DSL, the "pattern language"

Wow, I've never thought of it, but "syntax"-highlighting for binary files would be awesome.. e.g. "these bytes indicate the beginning of the next frame" (when talking about MP3/video files), maybe with mouseover support where it says e.g. "this value at this location indicates it's a $FOO variant of the file".

Anyone know of such a tool?

010 editor has something like this. Okteta too. They both use DSLs to represent formats