libass is a portable subtitle renderer for the ASS/SSA (Advanced Substation Alpha/Substation Alpha) subtitle format. It is mostly compatible with VSFilter.
Source code is available from our GitHub repository.
Please use the issue tracker to report bugs or feature requests. We have an IRC channel, too. Talk to us on irc.freenode.net/#libass.
The following projects/companies use libass:
- GStreamer (assrender plugin)
- Kodi (XBMC)
- PunkGraphicsStream (BD subtitle encoder)
- MX Player
Information about the ASS format:
- ASS specification (incomplete)
- ASS override tags (Aegisub manual)
- VSFilter source code (Guliverkli2)