Free online SSA to SMI converter

A media player, television, or older Windows-based video application may require SAMI subtitles instead of SSA. Converting the file preserves timed dialogue while adapting it to the target player's subtitle parser.

What the SSA format is

SSA (SubStation Alpha) is a text-based subtitle format used for timed dialogue with detailed style and layout controls. An .ssa file can contain script metadata, video resolution, font styles, dialogue events, positioning data, and override tags for colors, fonts, karaoke timing, and screen placement.

SubStation Alpha and Aegisub create SSA files, while Subtitle Edit can open and save them. SSA is common in anime releases, fansub archives, and video projects that use positioned or highly styled captions. The related ASS format extends SSA and is also supported by many of the same subtitle editors.

What the SMI format is

SMI, also called SAMI (Synchronized Accessible Media Interchange), is an HTML-like subtitle format originally associated with Microsoft media software. An .smi file stores timed entries with elements such as <SYNC Start=...> and can use language or caption classes for multiple subtitle tracks.

SAMI is useful when a legacy Windows media workflow or a specific television, set-top box, or media player expects the format. Its markup supports multilingual captions, but it generally represents SSA styling and positioning less precisely. SAMI timestamps are normally expressed in milliseconds, whereas SSA timestamps use centiseconds, so conversion can involve rounding.

How to convert SSA to SMI

Subtitle Edit is a suitable desktop option on Windows because it parses subtitle events instead of merely changing the filename extension.

1. Back up the original .ssa file.
2. Open Subtitle Edit and choose File → Open, then select the SSA file.
3. Check the dialogue, timestamps, line breaks, and special characters. If accented or non-Latin text is corrupted, reopen the file using the correct source encoding.
4. Choose File → Save as. Select SAMI or the .smi format in the save dialog, then save the output.
5. Load the SMI file with the intended video player. If the player detects subtitles automatically, give the subtitle and video the same base filename and store them in the same folder.

You can also convert the file on 101convert.com for free without installing software: upload the SSA file, choose SMI, start the conversion, and download the result. Test the downloaded file before removing the original.

Quality and compatibility limits

• Dialogue text and basic timing usually transfer, but SSA features do not map one-to-one to SAMI.
• Fonts, outlines, shadows, rotations, drawing commands, karaoke effects, transitions, and precise placement may be simplified or discarded.
• Review events that use tags such as \\pos, \\move, or \\k; the text may remain while its intended position or animation is lost.
• Check synchronization near scene cuts. Centisecond-to-millisecond conversion can alter timestamps slightly, and frame-rate changes can cause larger timing errors.
• For multilingual output, verify that the converter writes the required SAMI language classes and that the target player can select them.
• Use UTF-8 when the target device documents UTF-8 support. Older players may require a regional character encoding, and an otherwise valid SMI file can display replacement characters on those devices.