Sonus

Sonus is a local-first desktop music player that streams audio from YouTube Music using yt-dlp — no ads, no accounts, no cost. It features a retro pixel-art GUI built with egui, a 10-band equalizer, recommendation radio, and a SQLite-backed library. Cross-platform: Linux, Windows, and macOS.

Features

• YouTube Music search — music only, no vlogs or random videos
• Recommendation radio — keeps playing after your queue ends, falling back to your listening history when the network radio fails
• Native desktop GUI — egui + eframe with pixel-art styling, no browser engine
• 8 built-in themes — Winamp Green, Osaka Jade, Amber CRT, C64, Midnight, Tokyo Night, Solarized Dark, Gruvbox — plus custom TOML themes
• 10-band equalizer — with presets, running in the audio pipeline
• Library — SQLite-backed tracks, playlists, favourites, play history
• Low memory — streams instead of hoarding; audio is never fully downloaded

Architecture

A Cargo workspace of 8 crates, each with a single responsibility:

crates/
  sonus-core/     Shared types: Track, Queue, Playlist, Theme
  sonus-deps/     Downloads/verifies/updates yt-dlp & ffmpeg binaries
  sonus-ytdlp/    yt-dlp subprocess: search, radio, metadata, streaming
  sonus-audio/    Playback engine (rodio), ring buffer, EQ, spectrum
  sonus-library/  SQLite library: tracks, playlists, history, favourites
  sonus-cache/    LRU file cache for audio data
  sonus-gui/      GUI: pixel-art widgets, views, theme manager
  sonus/          Binary entry point and CLI

How playback works

Audio flows yt-dlp → ffmpeg → ring buffer → rodio. The GUI owns the queue and decides what plays next; AudioEngine is not Send (rodio’s output stream holds platform-specific handles), so it lives on a dedicated audio thread and the GUI talks to it over a channel. A pre-roll gate holds the sink until enough audio has buffered, so the clock never runs ahead of the sound.

Distribution

Prebuilt packages for every release: Windows installer (Inno Setup) + portable zip, Debian .deb, Fedora .rpm, macOS .app bundle, and an AUR PKGBUILD. The GUI can also self-install yt-dlp and ffmpeg on first launch — no terminal required.

Engineering highlights

• Custom pixel-art widget set (seven-segment display, spectrum analyzer, beveled panels, retro sliders) rendered entirely through egui’s paint API
• SHA-256 verification of downloaded dependency binaries
• Offline-aware radio that degrades gracefully from network recommendations to local listening history
• Custom TOML theme format with automatic derivation of bevel/dim/shade variants