WHAT IS M4V?
Apple created the M4V file type from the MP4 format. M4V is used to store movies, TV series, and music videos in the iTunes Store. Note that M4V files from the iTunes Store may be copy protected. Some apps allow playback of unprotected M4V files, though. If you have a Windows PC, you can use QuickTime, but many mobile devices don’t fully support M4V. To learn how to avoid compatibility problems, just look through this table.
Based on the MP4 multimedia container format, Apple placed a level of protection on M4V files to prevent unauthorized reproduction. Aside from Apple’s FairPlay DRM copyright protection, files in the M4V format use the H.264 codec, which allows devices to store chapter information. As for sound, M4V uses AC-3 and AAC audio codecs. You won’t be able to play copy-protected files with M4V specifications without authorization, but you may also come across unprotected M4V content. You can open these files using third-party programs by changing the file extension from .m4v to .mp4.
Apple QuickTime Player, Apple iTunes, VLC, and others