Free online ASS to SMI converter

Some older televisions, standalone media players, and subtitle programs accept SAMI/SMI but not ASS. Converting lets you keep the dialogue and timing in a format those devices can read, although advanced visual effects usually require manual adjustment.

What the ASS format is

ASS (Advanced SubStation Alpha) is a subtitle format used for anime, karaoke, fansubs, and video projects that need precise visual control. It stores dialogue timing in centiseconds, named styles, fonts, colors, margins, screen positions, animations, karaoke effects, and inline override tags.

A typical file contains sections such as [Script Info], [V4+ Styles], and [Events]. Aegisub and Subtitle Edit can create or edit ASS files, while players such as VLC and mpv can render them. ASS is intended for subtitles whose appearance is part of the authoring work, not just for plain captions.

What the SMI format is

SMI is the extension commonly used for SAMI (Synchronized Accessible Media Interchange), a Microsoft-developed subtitle format. A SAMI file uses HTML-like markup with timed <SYNC> elements; its timestamps are normally expressed in milliseconds, and the caption text is placed inside markup.

SAMI can contain timed captions, basic formatting, multiple language tracks, and hearing-impaired text. It is supported mainly by older televisions, standalone media players, and Windows-oriented subtitle software. It does not provide ASS-level support for transformations, vector drawings, animated tags, complex positioning, or karaoke effects.

How to convert ASS to SMI

Using 101convert.com:

1. Open the built-in ASS-to-SMI converter on 101convert.com.
2. Upload the .ass file.
3. Choose SMI or SAMI as the output format and start the conversion.
4. Download the resulting .smi file. For playback, place it beside the video with a matching base name, such as movie.mp4 and movie.smi.

This method requires no installation. Do not upload confidential subtitle content unless the service’s handling of uploaded files meets your requirements.

Using Subtitle Edit:

1. Open Subtitle Edit and choose File → Open to load the ASS file.
2. Check the imported text, timings, line breaks, and any warnings about malformed override tags.
3. Choose File → Save as, select SAMI or SMI, and save with an .smi extension.
4. If an encoding option is available, try UTF-8 first. Use a device-specific legacy encoding only when the target device displays UTF-8 incorrectly.

Subtitle Edit is useful when the imported subtitles need inspection or correction before export. If the program asks how to handle unsupported formatting, retain the plain text and timing unless the target device explicitly supports the formatting.

Quality and compatibility limits

The conversion normally preserves subtitle text and cue start times, but ASS styling is reduced to the smaller set SMI can represent. Font choices, exact positioning, borders, shadows, fades, drawing commands, animated tags, and karaoke timing may be removed or approximated.

ASS commonly represents timing in centiseconds, whereas SAMI uses millisecond timestamps. Conversion can therefore round times; this is usually insignificant for ordinary dialogue but can affect frame-sensitive karaoke and rapidly changing captions.

Check the saved file in a subtitle-capable player and, when possible, on the actual television or media player. Device support varies: some require the subtitle and video to have identical base names, some accept only particular character encodings, and some recognize only specific filename casing or SAMI markup. If accented characters are corrupted, verify the file’s encoding and any declared character set before changing it, because an incompatible conversion can make the captions unreadable.