International Standard Recording Code
ISRC is sort of like an ISBN, but it's for recordings of music and music videos. It's an international, recommended unique identifier code assigned to a recording. The code was formed by IFPI (International Federation of Phonographic Industry).
IFPI also recommends ISRCs to be used for digital rights management tasks and audio fingerprinting - but fortunately doesn't tell how, and doesn't force its use. Some file formats - such as Ogg Vorbis - have a meta information field for ISRC code.