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.