A music library contains music-related materials for patron use. Collections may also include non-print materials, such as digitized music scores or audio recordings. Use of such materials may be limited to specific patron groups, especially in private academic institutions. Music library print collections include dictionaries and encyclopedias, indexes and directories, printed music, music serials, bibliographies, and other music literature. Types Traditionally, there are four types of music libraries: Those developed to support departments of music in university or college settings; Those developed to support conservatories and schools of music; Those housed within public libraries; Those developed as independent libraries or archives supporting music organizations. Musical instrument library A musical instrument library lends or shares musical instruments. Examples can be found in Canada; Perth, Australia; and Massachusetts, Illinois, Ohio, Washington and New Paltz, New York in the United States. Such libraries producing diapason is varying from orchestral instruments to ethno. With the development of the media industry (film production, production of computer games, advertising), musical works created using digital technologies have become especially in demand. Such a genre of musical composition as trailer music was born - music for film advertising (trailer, teaser). A similar genre is characterized by the use of various audio effects libraries and musical instruments. Over the past decade, a galaxy of digital musical instrument library companies has grown. Among the companies, such giants as Spitfire, Cinesamples, Heavyocity, Soundiron, Native Instruments etc. Some are focused on reproducing the sounds of the instruments of the classical orchestra in digital format, others on creating libraries of traditional folk instruments. Famous such libraries as of Arabic instruments, Turkish, Iranian, Indian, Japanese and others. The companies are focused on the production of digital instrument libraries, which are almost as good as the living ones in sound quality. Digitalization of musical instruments is a historical process that takes place in technogenic civilizations. Other uses Production music libraries license their copyrighted music for use in film, television, and radio productions. Performance libraries serve performing music groups, particularly large orchestras, by acquiring, preparing, and maintaining music for performance. Digital music libraries and archives preserve recordings and digitized scores or literature in a variety of electronic formats. Many music libraries dedicate part of their duties to digitizing parts of their collection and maintaining digital files. Digital preservation requires specific procedures to avoid decay, obsolescence, and loss. Digital materials may be part of a larger, physical