Captioner

Captioner is a free, open-source app for Mac, iPhone, iPad and Android that adds animated, word-by-word captions to videos. It transcribes the video with Apple's on-device speech engine, so nothing is uploaded and no account is needed, and burns the captions into a new video in the style the user picks. Fifteen caption styles are included, including highlight boxes, karaoke colors, typewriter reveals and single-word styles, and the font, size, case and colors can all be changed and saved as a preset. Captions can be edited in place, split, merged or translated, and dragged to any position on the video. Folders of clips can be exported in one batch or watched so that new files are captioned automatically, and speakers can be colored by voice. A logo or watermark can be added to every frame. Exports keep the original resolution, frame rate and bit rate, with the audio copied unchanged. The app is aimed at creators who make vertical shorts and social video clips, and it also accepts an existing SRT or WebVTT file in place of transcribing. The Mac version needs macOS 26 or later.