M4a
From Wikipedia, the free encyclopedia.

m4a is the abbreviation for MPEG-4 audio. Its protected form is m4p, with digital rights management. If a filename.m4a file is renamed filename.mp4 it should play in any device or program which supports MPEG-4 audio.

The original article can be found at: http://en.wikipedia.org/wiki/M4a.
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