Hmix

Hmix is an open-source software library designed to manage and mix multiple data streams, with emphasis on hierarchical composition and extendable plug-in architecture. It supports audio, video, sensor, and analytics streams and is designed to operate in real-time environments.

The project defines a graph-based core where processing elements, called nodes, are connected by edges to form a data flow. Node types include sources, mixers, transformers, joiners, and sinks. The graph can be built programmatically or via a configuration file; scheduling uses a deterministic pipeline to minimize jitter.

History: Hmix originated as a research prototype in the early 2010s at a university lab, with public releases beginning in 2013. It has since seen community-driven development and multiple major releases with improvements in performance and cross-platform support.

Features: real-time mixing and routing, hierarchical composition, modular adapters for audio backends (for example, ALSA and Core Audio) and video decoders, Python and C++ APIs, bindings for Node.js via WebAssembly, and a plugin interface for custom mixers, such as crossfades, dynamic range control, and time-stretched overlays. It includes built-in support for synchronization and latency budgeting, and diagnostic tooling.

Applications and reception: used in live events, media production pipelines, research experiments in sensor fusion, and educational labs. It has been noted for its modularity and portability, though adoption is concentrated within niche domains.

Licensing and community: released under a permissive license such as MIT or Apache-2.0, with ongoing maintenance by a community of contributors and occasional corporate sponsors.