/System/Library/Frameworks/CoreMediaIO.framework/Versions/A/Resources/VDC.plugin/Contents/Resources/VDCAssistant VDCAssistant is used by the CoreMediaIO Device Abstraction Layer Plug-In that provides video capture from some models of Apple FaceTime cameras and external third-party USB VDC-class cameras using AVFoundation Capture APIs. The process allows multiple applications to simultaneously capture from the same camera.
The binary is a part of CoreMediaIO public framework.