/System/Library/Frameworks/CoreMediaIO.framework/Versions/A/Resources/AVC.plugin/Contents/Resources/AVCAssistant AVCAssistant is used by the CoreMediaIO Device Abstraction Layer Plug-In that provides audio/video capture from FireWire (IEEE 1394) AVC-class devices (DV and HDV cameras and decks) using AVFoundation Capture APIs. The process allows multiple applications to simultaneously capture from the same AVC device.
The binary is a part of CoreMediaIO public framework.