File Extension MP4
File extension MP4 is used by MPEG-4 multimedia files, and is an open container format which can store digital audio, video and subtitle streams. MP4 files are commonly used to stream video over the Internet and are preferred over many other formats due to the ability to use different compression algorithms for audio and video streams. This allows higher quality audio and video than other formats without significant increases in file size.
The MP4 format is used to store video in MPEG-4 format, a series of compression standards which were defined by the Moving Picture Experts Group (MPEG) in 1988 with the primary purpose of streaming multimedia content over the Internet. Other applications of the MP4 file format include telephony and media produced for television broadcast. The MPEG-4 standard builds on the previous MPEG-2 standard and has been designed to be scalable, making it suitable for any application from low-bandwidth video streams for use on mobile phones, to full high-definition content. MP4 files are usually used to store video clips, though support for subtitle streams also makes them suitable for the storing of DVD-content.
Though the MPEG-4 specification only officially supports the MP4 file extension, various others are also used to imply the contents of the file. The M4P file extension, for example, is used extensively by Apple to distribute MPEG-4 audio files with DRM copyright protection, and the M4A and M4B file extensions are used by audio books which contain audio streams as well as metadata such as chapter markers and hyperlinks. Despite their differing extensions, these are all implementations of the MPEG-4 format.
The MP4 file format is open, meaning that software developers can freely include support in media players, and as a result MP4 files can be opened using a wide range of applications such as Apple?s QuickTime, RealPlayer or Winamp. With the appropriate codec pack, it is also possible to open MP4 files in other popular media players such as Windows Media Player or Media Player Classic.