Convert SMI Subtitles to TTML Format
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About SMI
SMI or SAMI (Synchronized Accessible Media Interchange) is a format developed by Microsoft for subtitles in Windows Media Player. It uses an HTML-like syntax, which allows for basic styling and formatting of the subtitle text. It also has features for including multiple language tracks in a single file. Its usage has declined significantly with the wane of Windows Media Player.
About TTML
TTML (Timed Text Markup Language) is an XML-based standard for delivering timed text, meaning subtitles and captions, for web video and television broadcast. It's a W3C recommendation and is designed to be a professional, feature-rich format for the broadcast and streaming industry. It supports extensive styling, timing, and layout options and is the basis for many other professional formats like DFXP.
SMI vs TTML
| Feature | SMI | TTML |
|---|---|---|
| Styling Support | true | true |
| Positioning Support | true | true |
| Animation Support | false | true |
| Learning Curve | intermediate | expert |
| Quality Rating | 3 | 5 |
| Patent Status | proprietary | open standard |
| Year Introduced | 1998 | 2010 |
Frequently Asked Questions
Is SMI still used?
SMI is largely considered a legacy format. While it was popular in the early 2000s, especially in some Asian markets, its proprietary nature and the rise of open standards like VTT have made it uncommon for modern content.
What are the advantages of SMI?
Its main historical advantage was its ability to include multiple languages in one file and its use of familiar HTML-like tags for styling, which was accessible to web developers at the time. However, modern formats have surpassed its capabilities.
Is TTML used by major streaming services?
Yes, TTML and its profiles (like DFXP for Netflix) are the backbone of subtitle delivery for many major streaming platforms, including Netflix, Hulu, and Amazon Prime Video, as well as in professional broadcasting. Its robustness and rich feature set make it ideal for these high-stakes environments.
Is TTML easy to create by hand?
No, TTML is not designed to be human-readable or easily editable by hand. Its XML structure is verbose and complex. It is typically generated and processed by professional authoring software and is not suitable for casual subtitling.
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