Data file used by AntiVir, an antivirus application for Windows; saves virus definitions, which contain signatures that are used for recognizing viruses on the computer system; often downloaded during software updates so the software can check for new viruses.
VDF files are saved to the AntiVir installation directory and have the filenames vbase000.vdf, vbase001.vdf, etc.
File format used by Valve's Source game engine; uses Valve's KeyValues format, which is a plain text format that saves key-value parameters in a tree hierarchy; used for various kinds of game metadata, including data for resources, installation scripts, configuration scripts, and visualization elements.
VDF files can often be seen when installing games distributed through Valve's Steam game client.
Filter plugin for VirtualDub, a video capture and processing utility program for Windows; adds extra features such as special effects and additional file support to the VirtualDub program.
VDF filters can be loaded into VirtualDub by clicking on the "Load" button in the Add Filters dialog box. They will be loaded automatically if the VDF files are placed in the plugins folder within the VirtualDub program folder.