VSTAU

VSTAU is an informal term used in audio software to describe cross-format compatibility between Steinberg's Virtual Studio Technology (VST) and Apple's Audio Units (AU) plugin formats. It is not an official standard or specification. The term combines VST and AU to describe tools, workflows, or packaging approaches that aim to allow plugins to run in hosts that use either format, or to enable developers to publish a single plugin family for multiple hosts.

Background and context: VST and AU have distinct software development kits, binary interfaces, and runtime expectations. VST has been predominant on Windows, while AU is native to macOS. Cross-format support has historically required additional layers, dual-format builds, or bridging approaches to make a given plugin usable across different host environments.

Implementation and scope: Common strategies involve multi-format development toolchains that can produce VST, VST3, and AU versions from a single codebase. Plugins may be distributed with separate binaries for each format, allowing hosts to load the appropriate version. Some workflows rely on wrappers or packaging setups that present a unified installation while delivering the correct format per host. Feature parity, parameter automation, and licensing considerations can vary between formats and implementations.

Reception and status: VSTAU remains a niche concept rather than a standardized pathway. Most producers rely on native formats for stability and performance within a given DAW. In practice, developers often publish plugins as multi-format packages to maximize reach, using frameworks that support multiple formats during the build process.

See also: VST, AU, JUCE, plugin wrapper, cross-format plugin development.