MOD is a sound module format used to store music tracks and uses a .mod filename extension. It features a collection of sample instruments, and the samples are assigned to varying music tracks. The sound samples are opened, depending on score notes. Today, MOD can be opened using various audio tracking programs.
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.