AP3 file format is a VS10XX VSOS App from Asprova – an APS (Advanced Planning and Scheduling) system for Microsoft Windows OS. In short, it saves the scheduling project created via Asprova. Naturally, other apps can use files with .ap3 extensions. Just be cautious with AP3 data from unknown sources.
ASF (Advanced Systems Format) is a digital multimedia format designed to save and open content online. It is the primary container for Windows Media Video and Windows Media Audio content. Today, ASF supports smooth playback on HTTP servers, media servers, and local storage with programs like Windows Media Player.