CamillaDSP is a real-time audio stream processing engine written in Rust. It captures audio from a configurable backend (ALSA, PulseAudio, PipeWire, CoreAudio, WASAPI, ASIO, or file), processes it through a user-defined pipeline of filters, mixers, compressors, and other DSP components, and outputs it to a playback device. The pipeline is defined via YAML configuration, supporting biquad filters, FIR convolution (with hand-optimized NEON and AVX+FMA SIMD kernels), loudness, limiting, noise gates, and dithering. A websocket-based control interface allows runtime adjustments of volume, mute, faders, and config reloads. The architecture is modular with separate threads for capture, processing, and playback, using a PI rate controller for buffer level regulation. Benchmarks demonstrate attention to performance. While primarily an application, the DSP filter implementations and utility components (ring buffer, conversion routines, rate controller) are reusable building blocks for audio software.
musikcube is a cross-platform, terminal-based music player and streaming server written in C++. It consists of a core library (`musikcore`) with a plugin-based architecture for decoders, encoders, audio outputs, DSP, and data streams. The project includes three distinct front-ends: a terminal UI (`musikcube`) built on a custom curses++ framework, a native Windows UI (`musikwin`) using a custom Win32 wrapper, and an Android remote client (`musikdroid`) written in Kotlin. The server plugin enables remote control and audio streaming via WebSocket and HTTP. The core manages a SQLite-backed music library with indexing, metadata extraction (via TagLib), and playlist management. Audio playback supports gapless and crossfade transitions, visualizers, and an equalizer. The system is designed for extensibility through a well-defined SDK interface set, allowing third-party plugins for decoders, outputs, and DSP. The codebase is mature (copyright 2004-2023) and shows signs of organic growth, with heavy vendored third-party dependencies and platform-specific code. While not architecturally pristine, it demonstrates solid engineering, a clean plugin API, and reusable UI frameworks.