one of the most common audio formats. The format was developed by Microsoft (in collaboration with IBM) and usually stores uncompressed audio data with pulse-code modulation, but it can be used to store sound processed with other audio codecs.
this is a lossless-format (and encoding algorithm) for Apple platforms. M4A is widely used in iPod players and as a component in QuickTime media-players. The m4a codecs decoder is found in open sources - this allows third party users to open files in that format.