YOUR VIDEO. YOUR DEVICE.

Subtitles, without the upload.

Add multiple selectable subtitles to your videos. All processing happens privately in your browser.

Browser MVP

Select your video

Recommended size (tested): Up to 29.2 MiB
Recommended length (tested): Up to 1 minute
Maximum size: Under 2 GiB in total
Maximum length: No fixed duration limit

Based on generated desktop tests. Longer or larger videos may work, but processing can fail even below the maximum size.

Drop a video hereor choose a file from your deviceChoose video

Validated path: H.264 video + AAC audio in MP4 or MKV. Other streams are checked and may require the CLI.

Add subtitle tracks

0 added

Drop subtitles or choose filesSRT and WebVTT · UTF-8

Your subtitle tracks will appear here. Language hints come from filenames; review them before processing.

Browser limits, stated plainly

Initial benchmark-based recommendation: 29.2 MiB on desktop Chromium and Firefox. This is fixture evidence, not a guarantee for every file or device. The selected engine has a documented 2 GB input ceiling, enforced here at 2 GiB. Output buffers and browser memory can fail below that ceiling. Duration is not a hard limit.

Some videos contain extra information or use formats this app cannot keep. Use the command-line tool for these files. Safari and mobile processing have not been tested yet. Engine licenses and source