Compare
TTML vs WebVTT
TTML is an XML-based timed-text specification used with profiles for caption and broadcast workflows. WebVTT is a practical format for subtitle tracks in web video.
Which format should you choose?
Consider TTML when a workflow requires a particular profile or richer subtitle presentation. Choose WebVTT for subtitle tracks in HTML video, after checking the target player.
Good fit for TTML
Broadcast and streaming captions
- Supplying styled timed captions to a system with an agreed TTML profile
Good fit for WebVTT
Web video captions
- Serving a separate caption track with an HTML video element
Basic information
| Field | TTML | WebVTT |
|---|---|---|
| Extension | .ttml, .xml | .vtt |
| MIME type | application/ttml+xml | text/vtt |
| Common uses | Broadcast and streaming captions | Web video captions |
| How to open | Open and validate with a TTML-capable subtitle tool using the target profile. | Open in a text or WebVTT subtitle editor, then preview with the target video. |
| Export or convert | When converting to WebVTT or SRT, review timing, placement, and styling that may not survive. | When converting from SRT, check timestamps, line breaks, and styling. |
Choose by use case
Supplying styled timed captions to a system with an agreed TTML profile
Broadcast and streaming captions
TTMLServing a separate caption track with an HTML video element
Web video captions
WebVTTKey point 1
TTML features and compatibility depend on the profile and implementation in use.
More on the differencesKey point 2
WebVTT is designed for web video captions and can be connected through HTML track elements.
More on the differencesMore on the differences
Follow the delivery specification and validate the chosen profile in the target environment. On conversion, check timing, positioning, styles, and line breaks for information that may not map directly.
- TTML expresses timed text in XML and may support presentation features required by a defined workflow.
- WebVTT is oriented toward web subtitle and caption tracks rather than a general broadcast interchange profile.
- Neither file contains the video itself; playback support must be tested with the actual player.
Frequently asked questions
Can every TTML feature be converted to WebVTT?
No. Some profile-specific styling or positioning may not map. Test representative captions after conversion.
Should I use TTML for subtitles on a website?
Use it if the web platform and workflow support the required TTML profile; otherwise WebVTT is commonly suited to browser video tracks.