Markdown SVG Renderer Adds MP4 Export for Animated SVGs

Simon Willison's markdown-svg-renderer tool, first built in May, has been upgraded with new features, most notably the ability to convert animated SVGs into MP4 videos directly in the browser. The tool allows users to paste Markdown or provide a URL to a CORS-friendly document or GitHub Gist, rendering SVG content with tabs for PNG, JPEG, and now MP4 export. The MP4 tab, added on 16 August 2026, analyzes the SVG for animations, estimates loop duration, renders frames, and uses ffmpeg.wasm (over 30MB) to compile them into an MP4 video. This enables sharing animated SVGs on platforms that do not support SVG animation natively. The tool is available at markdown-svg-renderer, and an example URL with a Gist is provided. Willison notes his fondness for drawing pelicans riding bicycles, which motivated the tool's development. The post also mentions a sponsorship option for $10/month offering a curated email digest of LLM developments.