Add your ITT file
Drop one or more .itt files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
ITT to SMI
Converting a .itt file to .smi extracts the document's content from its office package into a portable form. Free, private, and validated — the file never leaves your browser.
Private for supported formats — processed in your browser
Runs on your deviceConvert supported files
Drop ITT files here
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.About converting iTunes Timed Text to SAMI captions
Converting a .itt file to .smi extracts the document's content from its office package into a portable form. An .itt file is an iTunes Timed Text document: a constrained TTML profile that Apple defined for subtitle delivery to the iTunes Store and Apple TV. Its defining trait is timing — cues are addressed in SMPTE timecode (HH:MM:SS:FF) against a frame rate declared in the document header.
An .smi file is a SAMI caption document: HTML-like markup in which <SYNC Start=…> elements mark the millisecond at which a caption appears, and the caption runs until the next SYNC. Microsoft designed it as an accessibility format, so a single file can carry several languages selected by CSS class. For this route the practical draw is several language tracks in one file, chosen by class and plain text and editable anywhere — balanced against never formally standardised, so real-world files vary in structure, which is worth knowing before you commit a large batch.
Why convert ITT to SMI?
The practical trigger for this conversion is usually a mismatch: with .itt, frame timecodes are meaningless without the declared frame rate, so a mis-set header shifts every cue. Switching to .smi buys you several language tracks in one file, chosen by class, which is why it is the better fit for captioning legacy Windows Media and Silverlight content. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
ITT vs SMI at a glance
| Aspect | iTunes Timed Text (.itt) | SAMI captions (.smi) |
|---|---|---|
| Format type | Text-based — characters and structure, so there is no visual quality loss | Text-based — characters and structure, so there is no visual quality loss |
| How it stores data | timing is frame-accurate: begin and end are HH:MM:SS:FF timecodes resolved against ttp:frameRate, optionally scaled by ttp:frameRateMultiplier for drop-frame rates such as 23.976 | the document has an HTML shape: <SAMI> wrapping <HEAD> with a <STYLE> block and <BODY> with the SYNC elements |
| Strongest at | delivering subtitles to Apple's ingest specifications | captioning legacy Windows Media and Silverlight content |
| Weak spot | frame timecodes are meaningless without the declared frame rate, so a mis-set header shifts every cue | never formally standardised, so real-world files vary in structure |
| Metadata | the frame-rate parameters are read because timing depends on them; styling attributes are dropped, since millisecond caption targets have nowhere to record them | style-class and title information describes presentation and language selection, not the cues; conversion keeps timing and text |
Pick SMI as the output
Select .smi in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if SMI is selectable, the route is real and validated.
Convert on your device
Press Convert. The package is unzipped in memory and its XML content parsed locally; nothing is uploaded.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid SMI file. Outputs keep the original filename with the .smi extension.
ITT to SMI questions, answered
Will converting ITT to SMI lose quality?
There is no visual quality to lose — itt is text-oriented and smi is text-oriented, so the question is structural fidelity. Text, ordering, and basic structure are preserved; complex layout, embedded objects, and styling beyond the target's model are simplified.
Is it private to convert ITT files here?
Yes — the .itt file is processed inside your browser tab and never uploaded. The package is unzipped in memory and its XML content parsed locally; nothing is uploaded. Close the tab and the file is gone from memory.
Where will the SMI file work?
Windows Media Player, VLC, PotPlayer, and MPC-HC read .smi, and Subtitle Edit converts it. Browsers do not. Novus Convert parses the SYNC blocks locally with document types and external entities refused and script and style content removed before any text is read, then writes any of the twelve timed-text targets.
Will the SMI file be bigger or smaller than my ITT?
It depends on the content: the document has an HTML shape: <SAMI> wrapping <HEAD> with a <STYLE> block and <BODY> with the SYNC elements. Convert one representative file first and compare before batch-processing a large set.
What happens to the metadata in my ITT file?
In .itt, the frame-rate parameters are read because timing depends on them; styling attributes are dropped, since millisecond caption targets have nowhere to record them. Re-encoding through the browser pipeline does not carry embedded metadata into the output, which doubles as a privacy scrub — check the exported file if you specifically need tags preserved.
Can I convert SMI back to ITT?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .itt → .smi → .itt is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.