WAV, sometimes called WAV, is an audio container format developed by IBM and Microsoft and comes with a .wav filename extension. Unlike popular formats like MP3 and MP4, WAV isn’t a lossy format, so it’s bigger and less popular. WAV files can be opened on various OS platforms via software like Windows Media Player, MPlayer, VLC Media Player, and more.
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.