Open-source components
Our piano player and recording studio run inside your browser. These optional libraries make local video export possible. Your performance is not uploaded to our servers.
FFmpeg WebAssembly
Optional MP4 conversion uses @ffmpeg/core 0.12.10 (GPL-2.0-or-later), including the GPL-licensed H.264 encoder libx264. The engine downloads on demand from jsDelivr only after you select Convert to MP4. It is about 30 MB; your recording stays on the device.
See corresponding source and build scripts, project licensing, and FFmpeg source. Codec patents may present separate obligations in some jurisdictions.
JavaScript libraries
@ffmpeg/ffmpeg 0.12.15 and @ffmpeg/util 0.12.2 are MIT-licensed: source. @fix-webm-duration/fix 1.0.1 is MIT-licensed: source.
Limitations
MP4 conversion is CPU- and memory-intensive, especially on mobile. It may fail on older devices. Your original WebM remains downloadable. The system share sheet does not automatically publish to TikTok, X or any social service.