.ASS file extension

This is the basic program to work with .ASS extension


Aegisub Aegisub Subtitle Script

Aegisub is an open-source application carefully designed to help you create, modify, correct, and synchronize subtitles in any language for your favorite movies and other video files. This feature-rich tool comes with all the functions required to produce high-quality professional subtitles in the most intuitive and straightforward way... (more)

The program works with the following extensions: srt, sub, ssa, ass and ttxt

.ASS extension is also supported by the following programs:

Jubler subtitle editor

Jubler subtitle editor ASS Subtitle file

Jubler is a tool to edit text-based subtitles for Windows users.
Subtitle Workshop

Subtitle Workshop Subtitle File

It allows you to create, edit and convert text-based subtitle files.