Advanced SubStation Alpha (ASS) is an advanced text-based subtitle format that expands on SubStation Alpha (SSA). It supports extensive text formatting, styling, and animation options, making it ideal for creating detailed and visually appealing subtitles for videos. It is widely used in the fansubbing community and compatible with various media players and subtitle editors.

Advanced SubStation Alpha was introduced in 2002 as an enhancement to the original SubStation Alpha (SSA) format. Developed to cater to the needs of the fansubbing community, ASS added several advanced features, including support for multiple layers, alpha channels, and more sophisticated text styling and positioning options. These enhancements allowed for more detailed and visually appealing subtitles, which were particularly useful for complex typesetting and karaoke effects in anime and other multimedia content. ASS became the preferred format for many subtitle creators due to its robustness and flexibility, and it continues to be widely supported by subtitle editors like Aegisub and media players such as VLC.