Cog is an open sourceaudio player for Mac OS X. The basic layout is a single-paned playlist interface with two retractable drawers, one for navigating the user's music folders and another for viewing audio file properties, like bitrate. Along with supporting most audio formats compatible with Mac OS X's Core Audio API, Cog supports a wide array of other audio formats, along with their metadata, which are otherwise unsupported on OS X.
In April 2006, Cog joined other OS X audio software Max and Tag in an effort by the respective authors to consolidate OS X open source audio software on the internet. Subsequently, the Cog website was redesigned to Tag and Max's website design, and its forums were also moved to the Tag and Max Forums. In July 2007, Cog moved to its own separate forums shortly before the release of version 0.06.