Search by sound is the retrieval of information based on audio input. There are a handful of applications, specifically for mobile devices that utilize search by sound. Shazam (service), Soundhound (previously Midomi), Axwave, ACRCloud and others have seen considerable success by using a simple algorithm to match an acoustic fingerprint to a song in a library. These applications take a sample clip of a song, or a user-generated melody and check a music library/music database to see where the clip matches with the song. From there, song information will be queried and displayed to the user. These kind of applications are mainly used for finding a song that the user does not already know. Searching by sound is not limited to just identifying songs, but also for identifying melodies, tunes or advertisements, sound library management and video files.