FourCC (literally, four-character code) is a sequence of four bytes used to uniquely identify data formats. The concept originated in the OSType scheme used in the Macintosh system software and was adopted for the Amiga/Electronic Arts Interchange File Format and derivatives. The idea was later reused to identify compressed data types in QuickTime and DirectShow.
Overview
FOURCC is short for "four character code" - an identifier for a video codec, compression format, color or pixel format used in media files. A character in this context is a 1 byte/8 bit value, thus a FOURCC always takes up exatly 32 bits/4 bytes in a file. Another way to write FOURCC is 4CC (4 as in "four" character code). The four characters in a FOURCC is generally limited to be within the human readable characters in the ASCII table. Because of this it is easy to convey and communicate what the FOURCCs are within a media file. AVI files is the most widespread, or the first widely used media file format, to use FOURCC identifiers for the codecs used to compress the various video/audio streams within the files. Some of the more well known FOURCCs include "DIVX", "XVID", "H264", "DX50". But these are just a few of the hundreds in use.
