.SSA

.SSA file extension

This is the basic program to work with .SSA extension

Aegisub

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

.SSA extension is also supported by the following programs:

Subtitle Workshop

Subtitle Workshop Subtitle File

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

Jubler subtitle editor SSA Subtitle file

Jubler is a tool to edit text-based subtitles for Windows users.
Sub Station Alpha

Sub Station Alpha Sub Station Alpha 4

Subtitles modifier

Subtitles modifier

A complete and easy-to-use tool to modify and improve your subtitle files.
SubViewer

SubViewer SubViewer3

SubViewer is a utility for adding and synchronizing subtitles .