VIDEOMARKUP

videoMarkup is a tool, designed for media professionals, to easily draw over video files frame-by-frame. Presents as a single-user interface with a 720p video markup window. This code was developed in part by Claude Sonnet 4.6 & Gemini Flash.
Features:

Vector-based pen markup and note annotation

Pen-input, pen pressure sensitivity, size and color adjustment,

Color sampling using Chrome color picker

Export independent markup files as .json file, and import with ease. Users can send json files to edit or expand on each other's markup without sending video files.

Export annotated video as .mp4

Realtime scrubbable video and audio playback.

Copy and paste annotations from frame to frame, easily cursor between annotations

Standalone, offline functionality. Sends & recieves no data, keeps your content secure on local storage.

See the source code.

Try it out in Chrome. Click the "Install" button in your address bar to download. May not render properly in other browsers.