Supported video and subtitle formats.

Check the file before uploading, and choose the output based on whether captions should be permanent or controlled by the player.

Last updated August 26, 2026

Video uploads

The uploader accepts MP4, MOV, WebM, and MKV video files. A file must contain a readable video track and spoken audio for automatic transcription.

Upload and duration limits

Guests and Free accounts support videos up to 10 minutes and uploads up to 500 MB. Starter raises the limit to 120 minutes and 5 GB.

Captioned video output

Export an MP4 with captions permanently burned into the picture. Free exports support up to 1080P, while Starter supports up to 4K.

Separate subtitle files

Download SRT for broad platform support, VTT for web players, or TXT when you only need the transcript text. Separate files preserve editable text outside the rendered video.