Convert SRT to TTML Online Free
Convert SRT subtitle files to TTML XML format for broadcast, streaming platforms, and professional subtitle delivery systems. ChangeThisFile generates valid W3C TTML output.
By ChangeThisFile Team · Last updated: March 2026
ChangeThisFile converts SRT to TTML on a secure server. Upload your SRT subtitle file and it is converted to W3C TTML XML format with proper namespaces and begin/end attributes. Files are auto-deleted after conversion. Free with no signup required.
Convert SRT to TTML
Drop your SRT file here to convert it instantly
Drag & drop your .srt file here, or click to browse
Convert to TTML instantly
SRT vs TTML: Format Comparison
Key differences between the two formats
| Feature | SRT | TTML |
|---|---|---|
| Structure | Plain text blocks | XML with namespace declarations |
| Styling | Basic bold/italic tags | Full CSS-like XML attributes |
| Positioning | Not supported | Named regions with coordinates |
| File size | Compact | Larger due to XML overhead |
| Editability | Any text editor | XML editor recommended |
| Use case | Consumer video players | Broadcast and streaming platforms |
| Standard | Informal | W3C TTML 1.0 / 2.0 |
When to Convert
Common scenarios where this conversion is useful
Submitting subtitles to a broadcast delivery system
Many broadcast networks and streaming platforms require TTML for subtitle ingest. Converting SRT to TTML makes your subtitles compatible with professional delivery specifications.
Integrating subtitles into a professional NLE workflow
Professional non-linear editors like Avid Media Composer and Adobe Premiere handle TTML in broadcast production workflows. Converting SRT to TTML bridges the gap from consumer to professional formats.
Distributing subtitles to SMIL-based media servers
TTML is closely related to SMIL and is used in adaptive streaming. Converting SRT to TTML enables subtitle delivery via MPEG-DASH and HLS streams that support TTML side-cars.
How to Convert SRT to TTML
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1
Upload your SRT file
Drag and drop your SRT subtitle file onto the converter, or click browse to select it. The upload is encrypted.
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2
Server-side conversion
The server parses each SRT cue, converts timestamps to HH:MM:SS.mmm TTML format, and writes a well-formed TTML XML document with standard namespace declarations.
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3
Download the TTML
Save your converted TTML file. The server copy is automatically deleted after processing.
Frequently Asked Questions
TTML (Timed Text Markup Language) is the W3C standard for subtitle interchange in professional, broadcast, and streaming contexts. Netflix, Amazon, and Disney+ all use TTML variants internally.
Yes. The output conforms to W3C TTML 1.0 with standard tt, head, body, div, and p elements and xmlns namespace declarations.
SRT HTML tags like <b>, <i>, and <u> are preserved as plain text in the TTML p elements. Mapping them to TTML tts:fontStyle attributes would require additional processing not included in this basic converter.
Yes. The output TTML file is valid XML that you can edit in any text or XML editor to add region definitions, styling attributes, and positioning as required by your delivery specification.
The converter outputs HH:MM:SS.mmm format (with a period before milliseconds), which is the standard TTML timeExpression format.
Netflix and Amazon use strict TTML profiles (IMSC-1 and IMSC-2) with specific requirements. The converter produces standard TTML that may need additional attributes and styling to meet their exact specs.
Yes. Files are transferred over HTTPS and automatically deleted after the TTML is ready for download.
SRT files are plain text. The 50 MB server limit is not a concern for subtitle files.
You can validate the XML well-formedness with any XML parser. For TTML-specific validation, use the W3C's TTML validator or the Inband Caption Test Suite.
Yes. ChangeThisFile supports TTML to SRT conversion for round-tripping between formats.
Related Conversions
Need to convert programmatically?
Use the ChangeThisFile API to convert SRT to TTML in your app. No rate limits, up to 500MB files, simple REST endpoint.
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