What is M4A?

M4A is an extension of the file used with MP4, also known as files of the moving image-4 (MPEG-4). MP4 files are known as "container" files. Because they can contain many types of content, including sound, video, subtitles and three-dimensional (3-D) objects, it is not possible to determine the type of content contained in the MP4 file based on the standard MP4 file extension. To solve this problem, Apple® created the M4A file extension and marked files only for sound.

There are no differences in the format between files with M4A extensions and those with MP4 extensions. MP4 is the only extension of the ensemble officially recognized by the International Standardization Organization (ISO). However, the extension of the M4A file is generally used for non -nicatal management rights, audio content, while MP4 extensions are usually used for MP4 files that contain audio and video. The file type is based on Apple® QuickTime format and is identical to the QuickTime Movie (MOV) file format. MP4 format, howeverIt also has formal support for initial descriptors of objects (IOP) and other MPEG specifications. The MP4 file format is the basis for other file formats, such as 3GP and a group of film moving (JPEG) 2000. The original version of the MP4 file format was released in 2001 and the second version was released in 2003.

MP4 file format is often confused as directly related to MP4 players. The MP4 player is a common name portable media player that is sold as an audio layer 3 (MP3) MPEG. Not only do MP4 players are not specially designed to play MP4 or M4A files, many of them are not in fact unable to play such files.

MP4 files use sound compression and videos to reduce file size. Apple® lossless encoder manages to compress files to MP4 container format with less data loss than other "lossy" formats such as advanceE -sound codecs (AAC) and MP3. The M4A files also have higher sound quality than MP3 and other sound files of the same size. MP4 files can be played on many popular portable sound players, including iPod.