Unique material identifier
The Unique Material Identifier (UMID) is a standard (SMPTE 330M) for generating unique identifications (IDs) of multimedia files and data streams .
The length of a UMID is 32 bytes (Basic UMID) or 64 bytes (Extended UMID). The Basic UMID is only intended for unique identification. The Extended UMID also contains data on the location, the time and the creator.