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Khan Academy-style explainer videosNew

Turn a script into a blackboard lesson: a black board, a thin pen writing by hand in coloured ink, simple doodles, and a calm voice explaining as it draws. It copies the look of Khan Academy's grammar series.

950 downloads

A finished board from the lesson "What is an AI agent?"

See one

"What is an AI agent?", the first lesson of a six-part series made with it (3 minutes):

It makes vertical 9:16 videos too, for Reels, Shorts and TikTok. This one-minute roofing ad is one:

What you get

  • An MP4 at 1920×1080, or 1080×1920 for vertical
  • Handwriting drawn stroke by stroke, not typed on
  • Doodles traced from generated line drawings, in the board's ink colours
  • A natural ElevenLabs voice that keeps talking while the pen finishes
  • A check of the finished video: its narration is transcribed and compared with your script

A board from the lesson on skills

How it works

  1. You write the lesson as a short Python file: what's said, and what gets written or drawn on each line (write, draw_image, shape, typed, clear). Seven worked examples come with it: the six-part AI agents series and the roofing ad.
  2. It draws the doodles the lesson needs, from a one-line description of each.
  3. It renders a still of every board first, so overlapping or cut-off words are fixed before the full render.
  4. It renders the video with the voice, then checks it by transcribing the narration against the script.

What you need

  • A Linux machine you can reach over SSH: it renders there, and scripts/setup.sh installs the engine, a Python 3.12 environment and the fonts on it
  • ffmpeg and uv on that machine
  • An ElevenLabs API key for the voice and a fal.ai key for the doodles