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.
MKA is a free Matroska Multimedia Container format that can store multiple audio, video, image, and subtitle tracks. It’s used to save typical multimedia content such as TV shows and movies and comes with a .mkv for video files. When used on audio files, it features a .mka filename extension, .mks for subtitles, and .mk3d for stereoscopic video files.