OSC
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OSC is a way to get different devices and applications to talk to each other. VRChat announced on February 16th 2022 OSC for Avatars[1]. Most commonly used to have body-,eye- and face trackers communicate with VRChat.
OSCQuery
OSCQuery is a protocol to connect OSC applications together easier. Information on how to connect with VRChat with OSCQuery. VRChat also provides a C# library on GitHub.
OSCQuery Libarys currently available to the public:
Typescript with example scripts on github by Jangxx: node-oscquery
Python with examples on the github readme.md vrchat_oscquery, An older vairant also more discriptive: tinyoscquery
Rust implementation with baseline functionally: oscquery
Resources
OSC Overview on the VRChat Documentation
Full OSCQuery proposal and how it functions while including example code