SAMI to ASS Converter
FileFlip converts SAMI to ASS entirely inside your browser, using FFmpeg compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert a SAMI file to ASS?#
- Drop your SAMI file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to ASS and the conversion starts on its own. FileFlip downloads 30.8 MB of WebAssembly the first time and nothing after that, then runs FFmpeg on your own machine.
- Save the ASS file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting SAMI to ASS lose quality?#
No. Subtitle cues are text, and converting SAMI to ASS rewrites the same timings and the same lines in the target's syntax. Anything ASS has no syntax for, such as positioning or styling, is dropped rather than degraded.
Is it safe to convert SAMI files online?#
Yes, because nothing is uploaded. FileFlip converts SAMI files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What SAMI to ASS actually does to the file#
Converting SAMI to ASS runs on FFmpeg, downloads 30.8 MB of WebAssembly the first time and nothing after that, rewrites the cues as text in the target's syntax, keeps cue durations.
| Engine | FFmpeg |
|---|---|
| Conversion path | One step: SAMI → ASS |
| Downloaded to your browser | 30.8 MB, once, then cached by your browser |
| Quality | Text preserved, unsupported styling dropped |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Cue durations | Kept | Carried through into the converted file. |
What is a SAMI file?#
A SAMI file is an HTML-flavored caption script built from <SYNC Start=milliseconds> blocks, each holding the caption text for one moment in the media, with CSS-style classes used to hold more than one language's captions in the same file.
Recognize SAMI as a legacy Windows Media caption file if it turns up alongside older video content; there's little reason to author new captions in it today.
Convert SAMI to SRT or VTT to caption video outside the Windows Media Player ecosystem, where SAMI support is inconsistent.
What is an ASS file?#
An ASS file is a SubStation Alpha v4+ script split into a Script Info section, a Styles section defining named formatting templates, and an Events section holding every line of dialogue with its timing, style reference and any positioning, karaoke or drawing overrides applied inline.
Use ASS when the subtitles need typesetting: positioned signs, karaoke, styled dialogue for multiple speakers, or effects timed to the video.
Convert ASS to SRT only when the destination can't render ASS at all, and only if losing every style, position and karaoke tag is acceptable, since none of that survives the conversion.
SAMI to ASS questions people ask#
Why does my SAMI file show captions in the wrong language?
A SAMI file can hold more than one language's captions in the same file, each under its own CSS-style class, and the player decides which class to display. If the wrong language shows, the player is choosing a different class than the one intended, not that the file is broken.
What is a SAMI (.smi) file?
A SAMI file is Microsoft's caption format from the Windows Media era, marking up timed captions with HTML-like <SYNC> tags in a file that Windows Media Player loads automatically when it shares a video's filename. The name stands for Synchronized Accessible Media Interchange.
Does Windows Media Player play SMI files automatically?
Yes. Windows Media Player looks for a .smi file with the same name as the video file in the same folder and loads its captions automatically, without the file needing to be selected manually.
What does ASS stand for in subtitle files?
ASS stands for Advanced SubStation Alpha, the styled subtitle format built by extending SubStation Alpha with an alpha channel for transparency, more override tags and better karaoke timing. The extension survived being an easy target for jokes because the format itself became the standard for typeset fansubs.