Drop a video file here or press Menu → Choose video.
Files never leave this device.
Files never leave this device.
0:00 / 0:00
Timeline00:00.000
No video — choose a video to time captions against
No subtitles yet — add one or generate them.
Tap the ruler to jump. Tap a block to select it and seek. Drag a block's ◀ ▶ edges to trim, drag its middle to move. Times shown under “Subtitles” stay exact — zooming never changes them.
No subtitle right now
Subtitles · 0 subtitles
Two subtitles overlap in time — only one can show at once. Open “Timing & more edits” on one of them to fix the times.
Generate subtitles
Listens to your video on this device and writes the words for you. Nothing is uploaded. The first run downloads a recognition model once (internet needed), then it works offline. Always check the words afterward.
English subtitles only. Speech in other languages is automatically translated into English.
Recognition model (advanced)
Kinetic captions
Word-by-word animation, timed to the video. Estimated timings are a rough split — check them below or measure. Measured timings come from the on-device model. Word timings save with the project.
No word timings yet — Kinetic mode shows plain subtitles meanwhile.
The Phrase focus style always shows the whole line — no checkbox needed. This box extends whole-line display to the other styles. “Words at once” applies only to word-by-word display.
Diagnostics (dev only, ?diag=1)
Model, audio levels, returned text, timestamp checks, repetition flags, errors. Nothing here leaves the device.
Hear what the model hears — the exact processed sound (not the original video). Compare with the video above.
More subtitle tools
Dictate with microphone
Voice dictation is unavailable in this browser. Try Chrome or Edge on desktop, or load a subtitle file instead.
Press Start, play the video, and speak each line. Spoken lines become subtitles at the current video position. Your voice goes to your browser maker's speech service for this feature only.
Idle.
Style
The quick brown fox jumps over the lazy dog
Pick a look — the video preview updates right away, using the same layout as the exported video.
Customize style
Tip: select a subtitle, then use Preview to check it against the video frame. “↑ ↓” next to the preview nudges position while you watch.
Effects
Effects render the same in the preview and the exported video. Animation plays once per subtitle, timed to the video — never a looping decoration. Word-by-word karaoke highlighting is not offered: the app has no word timestamps and will not fake them.
Export
Saves your video with the subtitles permanently visible, right on this device.
Checking what this browser can export…
High (1080p): Sharp full-HD detail. Larger file, slower export.
Subtitle file
A text file with all words and timings — useful for YouTube or editing later.
Details & support
No video loaded
Your work saves automatically on this device. Video files are never stored or uploaded — if a project can't find its video, it will ask you to select the file again.