Add your TTML file
Drop one or more .ttml 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.
TTML to SUB
Converting a .ttml file to .sub 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 TTML 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 Timed Text Markup Language to MicroDVD subtitles
Converting a .ttml file to .sub extracts the document's content from its office package into a portable form. A .ttml file is a Timed Text Markup Language document: an XML vocabulary in which each <p> element carries begin and end (or dur) attributes plus the caption text. It is the W3C standard that broadcast and streaming systems use as their interchange format for captions and subtitles.
A .sub file in the MicroDVD convention is a frame-based subtitle list: every line reads {startFrame}{endFrame}text, with a pipe character separating the lines inside one cue. Because the timing is expressed in frames rather than milliseconds, a MicroDVD file only means anything alongside the frame rate of the video it was timed to. For this route the practical draw is extremely compact — one line per cue and frame timing matches the source video exactly when the frame rate is known — balanced against meaningless without the correct frame rate; the wrong value drifts the whole file, which is worth knowing before you commit a large batch.
Why convert TTML to SUB?
The practical trigger for this conversion is usually a mismatch: with .ttml, far more verbose than SubRip or WebVTT for the same cues. Switching to .sub buys you extremely compact — one line per cue, which is why it is the better fit for playing back subtitles that were timed against a specific video rip. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
TTML vs SUB at a glance
| Aspect | Timed Text Markup Language (.ttml) | MicroDVD subtitles (.sub) |
|---|---|---|
| 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 | the root <tt> element declares the TTML namespace and optional ttp: parameters such as frameRate, tickRate, and timeBase | each cue is one line: {startFrame}{endFrame} followed by the text, with | separating multiple display lines |
| Strongest at | delivering captions to broadcast and streaming platforms that mandate a TTML profile | playing back subtitles that were timed against a specific video rip |
| Weak spot | far more verbose than SubRip or WebVTT for the same cues | meaningless without the correct frame rate; the wrong value drifts the whole file |
| Metadata | styling, layout, and region definitions are read past rather than applied: timing and text convert, presentation does not, and no external resource is ever fetched | there is no metadata section; the only header-like content is the frame-rate declaration, which is read on input and written on output |
Pick SUB as the output
Select .sub in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if SUB 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 SUB file. Outputs keep the original filename with the .sub extension.
TTML to SUB questions, answered
Will converting TTML to SUB lose quality?
There is no visual quality to lose — ttml is text-oriented and sub 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 TTML files here?
Yes — the .ttml 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 SUB file work?
VLC, MPC-HC, and most desktop players read MicroDVD .sub, and Subtitle Edit converts it. Browsers do not. Novus Convert reads the frame rate from the file's own {1}{1} declaration and falls back to 23.976 when none is present; a binary VobSub .sub is rejected with an explanation rather than being parsed as text. MicroDVD output is written at 25 fps with that rate declared in the first line, so a converted file round-trips to the frame.
Will the SUB file be bigger or smaller than my TTML?
It depends on the content: each cue is one line: {startFrame}{endFrame} followed by the text, with | separating multiple display lines. Convert one representative file first and compare before batch-processing a large set.
What happens to the metadata in my TTML file?
In .ttml, styling, layout, and region definitions are read past rather than applied: timing and text convert, presentation does not, and no external resource is ever fetched. 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 SUB back to TTML?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .ttml → .sub → .ttml is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.