Convert VTT to TTML Online Free
Convert WebVTT subtitle files to TTML XML format for broadcast delivery, professional subtitle tools, and streaming platforms. ChangeThisFile generates standards-compliant TTML output.
By ChangeThisFile Team · Last updated: March 2026
ChangeThisFile converts VTT to TTML on a secure server. Upload your WebVTT file and it is converted to W3C TTML XML with proper namespace declarations and begin/end attributes per cue. Files are auto-deleted after conversion. Free with no signup required.
Convert VTT to TTML
Drop your VTT file here to convert it instantly
Drag & drop your .vtt file here, or click to browse
Convert to TTML instantly
VTT vs TTML: Format Comparison
Key differences between the two formats
| Feature | VTT | TTML |
|---|---|---|
| Standard | W3C WebVTT | W3C TTML XML |
| Structure | Plain text cue blocks | XML document with hierarchy |
| HTML5 support | Native <track> element | Via polyfills/players |
| Styling | CSS STYLE blocks | XML tts:* attributes |
| Positioning | Cue settings inline | Named regions |
| Primary use | Web video players | Broadcast/streaming platforms |
| File size | Compact | Larger XML structure |
When to Convert
Common scenarios where this conversion is useful
Submitting web captions to a broadcast ingest system
If you created VTT captions for your website and need to deliver them to a broadcast network or professional streaming platform that requires TTML, converting VTT to TTML bridges the gap.
Converting captions for MPEG-DASH or HLS delivery
Adaptive streaming formats like MPEG-DASH support TTML as a sidecar subtitle format. Converting VTT captions to TTML enables subtitle delivery via DASH streams.
Delivering captions to a professional subtitle authoring tool
Tools like EZTitles, Cavena, and Swift subtitle systems work with TTML. Converting VTT to TTML makes web-origin captions compatible with these professional workflows.
How to Convert VTT to TTML
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1
Upload your VTT file
Drag and drop your WebVTT subtitle file onto the converter, or click browse. The upload is encrypted.
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2
Server-side conversion
The server strips the WEBVTT header and cue IDs, converts each cue's start and end times to TTML HH:MM:SS.mmm format, and wraps everything in a valid TTML XML document.
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3
Download the TTML
Save your converted TTML file. The server copy is automatically deleted after processing.
Frequently Asked Questions
When submitting subtitles to a broadcast delivery system, a professional streaming platform like Netflix or Amazon, or a subtitle management system that requires TTML as its input format.
VTT CSS styles are not automatically converted to TTML tts:* attributes. The output TTML contains unstyled <p> elements. Add tts:* attributes manually for styled subtitle delivery.
Yes. The output is a well-formed TTML document with standard tt, head, body, div, and p elements and proper xmlns declarations conforming to TTML 1.0.
VTT cue identifiers are discarded. TTML uses xml:id attributes which are not generated automatically by this converter.
Netflix and Amazon require specific TTML profiles (IMSC-1 and IMSC-2) with additional metadata. The base TTML from this converter may need profile-specific attributes added before submission.
Yes. Files are transferred over HTTPS and automatically deleted as soon as the TTML is ready.
VTT files are plain text and compact. The 50 MB server limit is not a concern.
Yes. ChangeThisFile supports TTML to VTT conversion for round-tripping between web and broadcast formats.
Yes. VTT files from YouTube (via yt-dlp or YouTube Studio export) are supported and convert correctly to TTML.
DFXP is an earlier distribution profile of TTML from 2006. Modern TTML (1.0 and 2.0) superseded DFXP. They are structurally nearly identical, which is why ChangeThisFile converts both.
Related Conversions
Need to convert programmatically?
Use the ChangeThisFile API to convert VTT to TTML in your app. No rate limits, up to 500MB files, simple REST endpoint.
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