$ show ebitengine/oto
oto is a low-level cross-platform audio playback library for Go. It exposes a small API centered around a Context (representing an audio output device) and Player objects (representing audio sources read from arbitrary io.Readers). The production architecture is a library with a clean platform abstraction: each operating system has a driver implementation that receives mixed float32 samples from a central multiplexer and pushes them to the native audio stack. Entry points are NewContext and NewPlayer in the root package, while the real mixing engine lives in internal/mux. The data flow is straightforward: user audio data enters via io.Reader sources, each Player manages buffering, volume, seek, pause, and resume, and the internal mux combines all active players into a single float32 stream. Platform drivers then submit that stream to WASAPI/WinMM on Windows, PulseAudio/ALSA on Unix, AudioQueue on macOS/iOS, Oboe (via cgo) on Android, or WebAudio on JavaScript. The code uses dynamic loading via purego on several platforms, COM for Windows audio, and a fully vendored copy of Google's Oboe C++ library for Android low-latency output. The codebase is well-engineered for a portable audio library. It demonstrates robust fallback chains (e.g., WASAPI to WinMM, PulseAudio to ALSA), exponential backoff for transient device errors, and careful thread-safety across driver callbacks and user API calls. It is an application library, not a data/research repository. Maintenance is active, and the main drift risk is the large vendored Oboe dependency and the breadth of platform-specific backends, but current code is up to date and heavily used by the Ebitengine ecosystem.
The LLM identified 2 files worth highlighting for reuse:
Core audio mixer that takes multiple io.Reader streams, manages their playback state and volume, and mixes all active players into a single float32 sample buffer for platform drivers. It uses sync.Pool to reuse byte buffers and carefully clamps mixed samples to avoid NaN/Inf propagation. This package is self-contained, tested, and could be extracted into another streaming audio engine with minimal modification.
Provides the root Context API plus a small atomicError helper that safely combines errors from multiple goroutines via Join/Load. The error aggregation pattern is generic and reusable in any concurrent Go system where background worker failures must be reported without data races.