advanced subtitle editor

 Originally created as tool to make typesetting, particularly in anime
 fansubs, a less painful experience, Aegisub has grown into a fully
 fledged, highly customizable subtitle editor.
 .
 It features a lot of convenient tools to help you with timing, typesetting,
 editing and translating subtitles, as well as a powerful scripting environment
 called Automation (originally mostly intended for creating karaoke effects,
 Automation can now be used much else, including creating macros and various
 other convenient tools).