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.
AC3 is an audio format designed by Dolby Digital to offer surround sound listening. This format is available on most Blu-ray and DVD media files and is played using a Dolby Digital DVD Player. Interestingly, AC3 can be output in up to six speakers of a home stereo system. On a computer, AC3 can be opened on VLC Media Player, Apple QuickTime Player, and Windows Media Player.
VLC Media Player Apple QuickTime Player Windows Media Player