Aegisub is a free, cross-platform open source tool for creating and modifying subtitles. Aegisub makes it quick and easy to time subtitles to audio, and features many powerful tools for styling them, including a built-in real-time video preview.
The Latest Release version is 3.4.2, released January 12, 2025. See the changelog for a list of changes. Check CI build. To cut down on the download size, the Windows “Full” Install includes only a US English dictionary for the spell checker.
One of the common complaints about the removal of committing changes in the 3.0 release is that when editing subtitles or translating subtitles into another language, it's often useful to be able to see the original version of the line as you work. 3.