Burn Subtitles into Video
Import an SRT, VTT or ASS file, style it, and watch a live preview before exporting an MP4 with the captions burned into the picture and the audio untouched. Nothing is uploaded — the video and the subtitle file both stay on your machine.
Why the preview is trustworthy
Most caption tools draw the live preview one way and burn the export another — different code, sometimes a different font engine entirely — so what you style is a guess at what you will get. Here, one function draws every caption: the same layout math, the same fonts, the same canvas drawing calls, whether it is running once for the frame under your cursor or once for every frame of the finished export.
That is also why fonts are loaded explicitly before anything draws, rather than left to load lazily the way a web page's text does. A canvas never triggers that lazy load on its own, so skipping the explicit step is exactly the kind of bug that looks fine on the machine that already has the font cached and wrong everywhere else.
Built on the same core as the other subtitle tools
This tool shares its parser, timing math and quality checks with the subtitle converter, the timing shifter and the fps converter. A file that has already been repaired, retimed or converted in one of those tools opens here exactly as you left it.
Frequently asked questions
Is my video uploaded anywhere?
No. Decoding, styling and re-encoding all happen in your browser using WebCodecs and the Mediabunny library. The only thing that ever leaves your device is nothing — not the video, not the subtitle file.
Does the audio survive?
Yes, and it is checked, not assumed. Audio tracks that do not need re-encoding are copied through untouched; where the container needs a different codec, the audio is transcoded rather than dropped. If a track genuinely cannot be carried, the tool tells you before exporting rather than shipping a silently mute file.
Will the export actually match the preview?
That is the point of the design: one drawing function renders both the live preview and every exported frame, using the same fonts, the same layout, the same code. What you see while styling is what gets burned in.
What subtitle formats can I burn in?
SRT, WebVTT, ASS and SSA. ASS/SSA styling — alignment, italics, karaoke word timing — carries through automatically; you can still restyle anything manually.
Which fonts are available?
Inter, IBM Plex Sans and Noto Sans (Latin, Cyrillic and Greek), plus your system's default sans as a zero-download option. None of these carry CJK or Arabic glyphs — a Japanese, Chinese or Arabic track still wraps and directs correctly, it just renders through the system font rather than one of the three bundled faces.
Is there a size or length limit?
Video files are capped at 2048.0 MB, since the whole file is decoded in your browser's memory. There is no hard duration cap — long or large files get an honest warning and a time estimate instead of a refusal.
What if my browser can't export video?
WebCodecs video encoding is not universal yet — some Linux and older Firefox builds lack it. When that happens, export is disabled with a plain explanation, and you can still download your styled, retimed subtitle file on its own.