m4v

M4V is a video container format developed by Apple as part of the MP4 family. It uses the .m4v filename extension and is based on the ISO Base Media File Format (ISOBMFF). Like MP4, an M4V file can contain video encoded with MPEG-4 or H.264/AVC, audio encoded with AAC or MP3, as well as subtitle tracks, chapters, and other metadata. The exact features depend on how the file was created.

While functionally similar to MP4, M4V is most commonly associated with content purchased or rented from the iTunes Store. Many iTunes videos are protected with Apple's FairPlay digital rights management (DRM), which restricts playback to authorized devices and applications. DRM-protected M4V files typically cannot be played on non-authorized players. In many cases, unencrypted M4V files behave the same as MP4 files and can be renamed to .mp4 to improve compatibility, though this does not bypass any DRM.

Availability and compatibility: Apple devices natively support M4V, and many third-party media players support unencrypted M4V. DRM-protected M4V playback depends on platform licensing and may require iTunes, Apple TV, or other compatible software.

See also: MP4, ISOBMFF, FairPlay, Apple iTunes.