ASS
Advanced SubStation Alpha
A heavily-styled subtitle format used by Aegisub and the anime fansub community. Supports per-cue fonts, colors, positioning, and karaoke timing.
In depth
ASS (Advanced SubStation Alpha) is the v4+ successor to SSA. It's a sectioned plain-text format with [Script Info], [V4+ Styles], and [Events] blocks. Beyond timing and text, ASS supports inline override codes for bold/italic/color/position, karaoke timing, transformations, and animated effects — making it the format of choice for typesetting in fansubs and stylized hardsubs.
When to use it
Use ASS when you need typography control beyond what SRT or VTT can express — kinetic typography, multi-style speakers, karaoke, or precise positioning. Aegisub is the industry-standard editor.
Frequently asked
What's the difference between SSA and ASS?+
ASS (v4+) added richer styling, soft margins, and override codes. Most modern tools speak ASS; SSA is legacy.
Can I play ASS files in a browser?+
Not natively. Browsers only read WebVTT from <track>. To use ASS-styled captions on the web, either burn them into the video (hardcode) or use a JavaScript renderer like JASSUB.
What are override codes?+
Inline tags like {\b1} (bold), {\i1} (italic), {\an8} (top-center alignment), and {\fs60} (font size). They start with a backslash inside curly braces.
The most common subtitle file format. Plain text with numbered cues and HH:MM:SS,mmm timestamps.
The W3C web standard for subtitles. Used by HTML5 <track> elements. Like SRT but with dot-separated milliseconds and styling support.
Subtitles permanently rendered into the video frame. They can't be turned off, but they look identical on every player and platform.