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.
FLV (Flash Video) is a video container format developed by Adobe Systems and comes with a .flv filename format. FLV is primarily used to stream audio, video, and text data such as subtitles. It supports MPEG-4 Part 10 (H.264) video codec and AAC sound.
RealPlayer, Apple QuicTime Player
VLC Media Player