Apple Video and Audio Formats Defined

MP4

     Movie or video clip that uses MPEG-4 compression, a standard developed by the Moving Picture Experts Group (MPEG); commonly used for sharing video files on the Internet.

MOV

    Common multimedia format often used for saving movies and other video files; uses a proprietary compression algorithm developed by Apple Computer; compatible with both Macintosh and Windows platforms.

M4V

   MPEG-4 file extension used for videos downloaded from the Apple iTunes store and includes music videos, TV episodes, and full-length movies; similar to a .MP4 file,  but may be copy-protected using Apple's FairPlay DRM copyright protection.

AAC

     Compressed audio file similar to a .MP3 file, but offers several performance improvements; examples include a higher coding efficiency for both stationary and transient signals, a simpler filter bank, and better handling of frequencies above 16 kHz; maintains quality nearly indistinguishable from the original audio source.