Differences with Specs

Nowadays most ASS subtitles are made in Aegisub, which uses libass and xy-vsfilter as renderer, so these two renderers become the de-facto spec of ASS.

It's almost impossible for DOM to render exactly same result in every pixels as VSFilter or libass, ASS.js will provide best efforts to accurate rendering.

Here are some differences:

Feature	VSFilter	libass	ASS.js
\be	✅	✅ not recommended	❌ same as \blur
\q3	✅	❌ same as \q0	❌ same as \q0
fadeaway{width,height}	✅	❌	✅
\k, \kf, \ko, \kt, \K	✅	✅	🚧 WIP