MPSub to TTML Converter
FileFlip converts MPSub to TTML entirely inside your browser, using FFmpeg compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert an MPSub file to TTML?#
- Drop your MPSub file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to TTML and the conversion starts on its own. FileFlip downloads 30.8 MB of WebAssembly the first time and nothing after that, then runs FFmpeg on your own machine.
- Save the TTML file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting MPSub to TTML lose quality?#
No. Subtitle cues are text, and converting MPSub to TTML rewrites the same timings and the same lines in the target's syntax. Anything TTML has no syntax for, such as positioning or styling, is dropped rather than degraded.
Is it safe to convert MPSub files online?#
Yes, because nothing is uploaded. FileFlip converts MPSub files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What MPSub to TTML actually does to the file#
Converting MPSub to TTML runs on FFmpeg, downloads 30.8 MB of WebAssembly the first time and nothing after that, rewrites the cues as text in the target's syntax, keeps cue durations.
| Engine | FFmpeg |
|---|---|
| Conversion path | One step: MPSub → TTML |
| Downloaded to your browser | 30.8 MB, once, then cached by your browser |
| Quality | Text preserved, unsupported styling dropped |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Cue durations | Kept | Carried through into the converted file. |
What is an MPSub file?#
An MPSub file is MPlayer's native subtitle script, opening with a FORMAT line that declares whether the lines that follow are timed in seconds or in frames, with each subtitle giving its gap since the previous line and its own duration rather than an absolute start and end time.
Recognize MPSub if it turns up as MPlayer's own subtitle export; there's little reason to author new subtitles in it outside that ecosystem.
Convert MPSub to SRT to get absolute, frame-rate-independent timecodes that any player can read.
What is a TTML file?#
A TTML file is an XML document that marks up timed text with a <body> of styled, positioned regions and a series of <p> elements carrying start and end times, built to move captions between broadcast and streaming systems without losing formatting.
Use TTML when delivering captions into a broadcast or streaming pipeline that expects it, such as Netflix's or the EBU's ingest specifications.
Convert TTML to SRT or VTT when the destination is a general video player rather than a broadcast or streaming delivery system, since those rarely parse TTML directly.
MPSub to TTML questions people ask#
What is an MPSub file?
An MPSub file is MPlayer's own subtitle format, where each line is timed by its offset from the previous line's end and its own duration, rather than by an absolute start and end timecode. A FORMAT line at the top of the file declares whether those offsets are measured in seconds or in frames.
Does MPSub timing break if the video's frame rate changes?
It depends on how the file was authored. An MPSub file with FORMAT=TIME is timed in seconds and stays in sync at any frame rate, but one authored in frame mode times its offsets in frame counts and drifts out of sync the same way MicroDVD does when the frame rate changes.
Can I convert an MPSub file to another format?
An MPSub file can be read and converted into a format like SRT that uses absolute, frame-rate-independent timecodes. Producing MPSub as an output is uncommon, since it's a format MPlayer exports rather than one other tools generate.
What is a TTML file used for?
A TTML file carries styled, timed captions through broadcast and streaming delivery pipelines, the way Netflix, the EBU and other distributors specify for ingesting subtitles. It's built for interchange between systems, not for opening directly in a typical media player.