Convert mv4 to heif

What is the difference between .mv4 and .heif?

Description: 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.; Based on HEVC (High-Efficiency Video Coding), the HEIF format is an image file container with one or multiple images and is the default image format for Apple Live Photos. It replaced the JPEG format as it's smaller in size and has lossless compression ensuring high-quality photos.