SHOUTcast is server software for streaming media developed by Nullsoft. It allows digital audio content, primarily in MP3 or HE-AAC format, to be broadcast to and from media player software, enabling hobbyists and professionals to create Internet radio networks. At least one streaming system, Icecast, licensed under the GPL exists.
SHOUTcast is cross-platform, and freeware.
SHOUTcast consists of a client-server model, with each component communicating via a network protocol that intermingles audio data with metadata such as song titles and the station name. It uses HTTP as a transport protocol, although multicast is another option.
SHOUTcast servers and clients are available for Microsoft Windows, FreeBSD, Linux, Mac OS X, and Solaris. Client-only versions exist on Windows Mobile, Android OS, Palm OS, Series 60, the iPhone, UIQ the PlayStation Portable, Nintendo DS (DSOrganize) and on the Wii.
The output format is supported by multiple clients, including Nullsoft's own Winamp, Totem, VLC media player, Amarok, XMMS, Zinf, Songbird, foobar2000 and Apple iTunes. Shoutcast servers are usually linked to by means of playlist files, which are small text files (usually with extensions .pls or .m3u) that contain the URL of the ShoutCast server. An attempt to visit that URL in a normal Web browser will usually result in a ShoutCast status page.
The most common use of SHOUTcast is for creating or listening to Internet audio broadcasts. SHOUTcast makes it possible to inexpensively set up an Internet broadcasting station, so hobbyists and large radio network owners alike can use it to set up their own broadcasting network for a fraction of the cost of a traditional AM broadcasting or FM radio station.
Some traditional radio stations use SHOUTcast to extend their presence onto the Web.