WMV (Windows Media Video) is a collection of video codecs with their respective coding formats introduced by Microsoft on its Windows Media framework. Initially, it was designed to compete with RM format on online streaming apps. It stores compressed videos and is even used to deliver content on Blu-ray/DVDs.
VLC Media Player MPLayer Media Player Classic Windows Media Player
M4R is a filename extension for AAC format, which is developed by Apple Inc. It is typically used to save custom iPhone ringtones from Apple iTunes. M4R can only be created from iTunes purchased songs and is usually DRM protected. It can open on iTunes, VLC Media Player, Apple QuickTime Player, and more.