Free tool · TTMLIMSC

Convert TTML
to IMSC

Drop in a .ttml (Timed Text Markup Language) file, get a clean .xml (Internet Media Subtitles and Captions) back. Internet Media Subtitles and Captions is the modern W3C streaming profile of TTML used by Netflix, Apple TV, and most streaming services. The conversion runs entirely in your browser — your captions never leave the page.

Input · TTML
Output · IMSC
Everything runs in your browser — no upload, no signup.
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Frequently asked

Why convert TTML to IMSC?+

Timed Text Markup Language is the W3C XML standard used by streaming platforms (Netflix, Disney+) and broadcast pipelines. Internet Media Subtitles and Captions is built for streaming delivery to HLS / DASH manifests and modern OTT ingest. Converting lets you take a file produced for one workflow and use it in the other without re-typing or re-timing anything.

Is timing preserved exactly?+

Yes. The converter only re-encodes the file structure — start and end times round-trip to within one millisecond.

Does any styling survive the conversion?+

Most styling drops in this direction. TTML supports inline styling and IMSC doesn't, so override codes, cue tags, and positioning attributes are stripped. Timing and text always survive.

Does this run on a server?+

No. The conversion is pure JavaScript running in your browser — files never upload anywhere. Works offline once the page is loaded.

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