SSA subtitle format
Overview
SSA (SubStation Alpha) is the predecessor of ASS. It is a rich subtitle format with styling, positioning and animation, but with fewer features than ASS. SSA files are still found in older subtitle releases, particularly from the early 2000s.
- Extension:
.ssa - Successor: ASS (Advanced SubStation Alpha)
- Complexity: High (but less than ASS)
- Browser support: None natively
Structure
SSA shares the same three-section structure as ASS but with the script type v4.00 instead of v4.00+:
[Script Info] ScriptType: v4.00 [V4 Styles] Format: Name, Fontname, Fontsize, PrimaryColour, ... [Events] Format: Marked, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text Dialogue: Marked=0,0:00:01.00,0:00:04.00,Default,,0,0,0,,Hello.
Differences from ASS
- Style format. SSA uses
[V4 Styles], ASS uses[V4+ Styles]. - Event fields. SSA events include a "Marked" field that ASS dropped.
- Fewer override tags. ASS added tags for karaoke, positioning and drawing that SSA does not support.
- Simpler animation. ASS extended animation capabilities significantly.
When you will see SSA
- Legacy fansub releases — anime subtitles from the early 2000s.
- Archival content — older subtitle databases and DVD rips.
- Older editing workflows — before ASS became standard.
Modern usage
New subtitle work uses ASS, not SSA. Most tools that support SSA also support ASS, and the two are treated as closely related. If you encounter an SSA file that fails to open in a modern tool, converting it to ASS first (using Aegisub or Subtitle Edit) may help.
Conversion
Subtitle Convert does not support SSA conversion directly. To convert SSA to SRT, VTT or ASS, use a subtitle editor like Aegisub or Subtitle Edit.