How to Convert SRT to SMI (SAMI) Subtitles | AllSubConverter
SMI (SAMI, Synchronized Accessible Media Interchange) is a subtitle format developed by Microsoft for Windows Media Player. It is still common in Korean subtitle communities and in workflows that need multiple language tracks in a single file. If you need subtitles for a legacy Windows media pipeline or a multi-language caption setup, you may need to convert SRT to SMI. This guide explains how SAMI works and what conversion involves.
What Makes SAMI Different
SAMI is essentially an HTML document. Captions live inside <SYNC Start=ms> elements, where the start time is an integer number of milliseconds. Because it is HTML-based, SAMI supports CSS styling and, importantly, multiple language tracks selected by CSS class. One SMI file can hold captions in several languages at once.
SRT, by contrast, is plain text with no styling, no positioning, and only one language per file. Converting SRT to SAMI wraps the subtitles in the HTML/SYNC structure and gives you a foundation you can style or extend with additional languages.
One SMI file can carry several languages. SRT carries one.
How the Conversion Works
Each SRT cue becomes a <SYNC> element. The converter reads the SRT start time, converts it to milliseconds, and sets it as the Start attribute. The cue text goes inside a <P Class=...> element, and line breaks become <br> tags. The result is a complete SAMI document with the required <SAMI>, <HEAD>, and <STYLE> sections.
Timing is preserved exactly, because both SRT and SAMI work in milliseconds. Nothing is rounded.
How to Convert SRT to SMI
Use our free SRT to SMI converter. Upload an SRT file and the tool produces a valid SAMI document. To add a second language, convert another SRT file and merge the SYNC elements under a different CSS language class.
Frequently Asked Questions
Does SAMI timing match SRT exactly?
Yes. SAMI start times are in milliseconds, the same unit SRT uses, so timing is preserved with no rounding.
Can one SMI file hold multiple languages?
Yes. That is one of SAMI main strengths. Each language is a CSS class, and the player lets the viewer switch between them. You build this by merging multiple converted files.
Will modern players read SMI files?
Most modern HTML5 players do not. SMI is best for Windows Media Player and legacy systems. For web video, convert SRT to VTT instead.