This is the x264vfw project ("x264vfw")
This project was registered on SourceForge.net on Jan 4, 2008, and is described by the project team as follows:
x264vfw is the VfW (Video for Windows) version of well known x264 encoder + ffh264 decoder (from FFmpeg/Libav project).
Of benefit to users, Open Source software is licensed so you can download and use the software free-of-charge. The source code for this software is made available free-of-charge, you (or a programmer you hire) can make changes to this software to better meet your needs, and you can release your changed code back to the community passing the benefit on to other users.
The exact license terms used by this project on their project summary page and in the licensing documents included in their downloads.
This FREE software is recommended in combination with MSI AfterBurner's Predator function for using external VFW codecs for video capture.