A company called Tune Hunter has filed a lawsuit in Texas Eastern District Court which alleges that a large number of companies are infringing on its patent for a music identification system.

Shazam, Samsung, Apple, Amazon.com, Napster, Motorola, Gracenote, Verizon Wireless, LG Electronics, AT&T Mobility, and Pantech Wireless have all been named in the suit. The company claims that Shazam violated the patent, and the other companies directly benefited from that infringement.

The patent covers: "a music identification/purchasing system, specifically to a method for marking the time and the name of the radio station in portable device such as a key holder, watch, cellular phone, beeper or the like which will allow the user to learn via internet or regular telephone the name of the song, artist and/or music company by matching the stored data with broadcast archive".

Shazam "listens" to songs and identifies them. It's available as an app in the iPhone App Store, as well as the Android and BlackBerry platforms. The company claims that it'll be available on 250 million devices by the end of the year.

The Texas Eastern District Court often features in patent lawsuits because it has a reputation for quick rulings which don't cost much in legal fees.