How do SDMI devices control digital audio?
SDMI compliant files utilize techniques such as digital watermarking to dictate “usage rules” to SDMI compliant devices. For instance, dictating SDMI devices enforce the rules placed on a song by the record company about the number of copies that may be made of a file. Usage rules usually prevent the public from exercising most types of fair use and do not expire when a work is due to pass into the Public Domain.
