Many M4V files are protected by Apple’s FairPlay Digital Rights Management (DRM) , which restricts playback to authorized devices and accounts.
Not all M4V files are protected. Tools like HandBrake often use ".m4v" as a default extension for standard MP4 videos to ensure compatibility with Apple features like chapter markers and AC3 audio. How to Open "4501731.m4v" 4501731.m4v
The M4V format is closely related to the more common MP4 format but is specifically optimized for the Apple ecosystem. Many M4V files are protected by Apple’s FairPlay