M4V是苹果开发的MPEG-4文件扩展名，与MP4相当。它对苹果iTunes商店的电影或视频进行编码。M4V和MP4的区别在于，M4V受到保护，如果任何人的电脑中有iTunes许可证，就可以播放。
M4V is Apple developed MPEG-4 file extension that is comparable to MP4. It encodes the movies or videos from Apple iTunes store. The difference between M4V and MP4 is that M4V is protected and it can be played if anyone has a license iTunes in his computer.
