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.
HEVC (High Efficiency Video Coding), is a modern video compression standard developed as the successor to the standard H.264 (Advanced Video Coding). In comparison to H.264, this format offers up to 50% better data compression while providing improved video quality at a similar bitrate. Today, HEVC is used by over 40% of video developers, only second to AVC.