Convert sub to ssa

What is the difference between .sub and .ssa?

Description: MicroDVD is a subtitle file format for digital video. Its name is derived from the MicroDVD Player, a media player application designed to play DVD videos along with subtitles, originally developed by Tiamat Software. The application was first released in 2000 but development ended in 2001. Media players that support the format are able to interpret MicroDVD subtitles and mix their contents with their corresponding video files.; SubStation Alpha (SSA) is a text-based subtitle file format used for captioning video and audiovisual media. It is widely used in fan-made anime music videos, karaoke videos, and other fan-made video projects. SSA files contain the timing, positioning, and content of each subtitle, which can be edited and modified with text editing software.