Open-source Claude Code skill renders Khan Academy-style blackboard explainer videos
_haiderfarooq · reddit · 2026-10-17
A developer open-sourced khan-explainer, a Claude Code skill (MIT, local, no API keys) that turns a prompt into a Khan Academy-style MP4: a pen draws stroke by stroke on a blackboard while a voice explains. Built on HTML canvas, Playwright, ffmpeg and the Mac's built-in say voice.
What it makes: blackboard/whiteboard lessons; draw-over-UI tutorials with arrows and numbered steps on your own screenshots; "Khanify" any YouTube video by keeping the speaker's real voice and drawing to their words (one 20-minute talk yielded 22 vertical clips).
How it works: a SKILL.md plus renderer; Claude writes beats (one spoken clause + its drawing), renders in seconds, then reads a contact sheet of every beat and fixes overlaps autonomously, iterating 3-4 times.
The key trick: the voice drives the clock — each line is spoken and measured first, then the pen gets exactly that long to draw, so no hand-typed timestamps and drawing can't outrun the words. Transferable lessons: self-grading output, caching the expensive step, measuring instead of eyeballing coordinates.
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