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PolyMeilex/Neothesia
Flashy Synthesia Like Software For Linux, Windows and MacOs
Neothesia is a MIDI visualizer that shows falling note blocks over a virtual piano keyboard, letting you follow along with a MIDI file like Synthesia — the commercial app it's explicitly trying to replace. Built in Rust with wgpu for rendering, it runs on Linux, Windows, and macOS and supports video export via an ffmpeg encoder crate.
Custom wgpu renderer with hand-written WGSL shaders for each visual element (waterfall, keyboard, glow effects) — this is why it actually looks good rather than just being a SDL2 rect dump. The workspace is well-decomposed: midi-file, midi-io, piano-layout, and nuon are independent crates with their own READMEs, so the rendering core isn't tangled with MIDI parsing. Flatpak packaging and Flathub distribution means Linux users can actually install it without building from source. Video encoding is a first-class feature with a dedicated ffmpeg-encoder crate, not an afterthought.
1,475 stars for a three-year-old project filling a real gap (Synthesia went closed-source) suggests limited reach — the GUI is functional but the UX still feels rough enough to slow adoption. No song library or built-in MIDI source: you have to bring your own .mid file, which raises the barrier for the target audience (people learning piano). The `neothesia-ai` crate exists but its purpose is completely undocumented — a mystery folder with audio and args modules. Configuration is in RON format, which is reasonable for Rust devs but confusing for musicians who just want to change colors.