Aegisub

Aegisub is a subtitle editing program designed for creating Advanced Substation Alpha (SSA) subtitles. It is the standard subtitle editor used for modern fansubbing. It contains features for translating, timing, visual typesetting, and can export to various subtitle formats. Aegisub is an open-source application written in C++, and supports Windows, macOS, and Linux. It can be extended with automation scripts using Lua or MoonScript.

History
Aegisub was started in 2005 by Niels Martin Hansen (jfs) and Rodrigo Braz Monteiro (amz) to replace the previously established subtitle editor Medusa. In 2012, maintenance of the project was mainly taken over by Thomas Goyne (plorkyeran), and version 3.0 was released. Regular releases continued until 2014, where version 3.2.2 would be the last official version to be released. Plorkyeran continued to periodically upload trunk builds on his website until 2016, with one more build being uploaded in 2018.

After Plorkyeran stopped actively maintaining Aegisub, several forks of the project appeared to fix critical issues. One fork was by wangqr, initially to fix aspects of the build system and improve high-DPI compatibility. Later, wangqr's fork added a CMake build system and further stability fixes, as well as a feature to time subtitle lines to changes in the video and a new audio back-end.

Another fork was started by CoffeeFlux and line0 under the name of the TypesettingTools organization. It initially focused on fixes and improvements critical to fansubbing, such as fixing color space conversion when loading videos. However, the fork soon put further feature additions on hold and in 2019 began a multi-year effort to port the build systems of Aegisub to a single platform-independent Meson build system. This was led mainly by CoffeeFlux and Myaamori. In January of 2021, the port was largely finished, in particular supporting generation of an installer file for Windows machines. Following this, CoffeeFlux received access to the upstream Aegisub repository in order to eventually release a new stable version. As of 2022, this is still in progress, with the biggest blocking issues being the merging of a Meson port to libass and security improvements to Aegisub's automatic updater.

With the TypesettingTools fork of Aegisub being mostly feature-frozen for an extended period of time, Ristellise (Shinon) started a new fork called AegisubDC. It was based on wangqr's fork, and began by releasing Windows builds of the application with the latest libraries - in particular libass and FFMS2. Later on, it would add multiple highly requested features, the most notable one being video panning and zoom, following a pull request to the upstream repository by moex3. The released builds also came with DependencyControl pre-installed. The fork only targeted Windows, although its new could be manually pulled into other forks by users. AegisubDC stopped active maintenance in March of 2022, and the repository was archived four months after, pointing users to arch1t3cht's new fork.

In June of 2022, arch1t3cht started a new fork, based on the TypesettingTools fork. Following the end of AegisubDC's maintenance and in anticipation of the TypesettingTools fork being eventually merged into the upstream repository to release a new stable version, the objective of this fork was to reconcile existing forks by rebasing the additions of wangqr's fork and AegisubDC onto the TypesettingTools fork and fixing any remaining issues. As such, it included additions like video zoom and (later on) wangqr's improvements to DPI awareness. Furthermore, it would add further requested features such as line folding, new audio and video providers, and new functions in the automation API. The repository is split into various branches for individual additions, in the hope that possible future forks will be able to easily follow the changes and pick which commits to keep. It builds on the work done by the TypesettingTools fork and thus uses its new build system to build on all major platforms, and releases installer files which also bundle DependencyControl and its required libraries.

As of 2022, fansubbing groups such as GJM recommend fansubbers to use arch1t3cht's fork of Aegisub.