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.