M4V is a video container that stores audio and video data used for iTunes files. Files of this type may be protected from illegal viewing and copying with Apple FairPlay DRM. In this case audio or video files should be bought in iTunes store. Not protected files can be viewed almost in any modern player because the format is based on MPEG-4 structure.

MTS is a high definition video extension developed by Sony and Panasonic companies for their high-definition consumer video cameras. Later these companies joined their forces in the Blu-ray Disc Association. AVCHD technology supports 720p and 1080i resolution. The format uses MPEG-2 or MPEG-4 codec for video compression and Dolby Digital AC-3 for audio compression. Blu-Ray players can playback MTS videos without compression.