This invention proposes arrangements for implementing processes free of signal degradation without entailing increased strains on transmission. Parameter information such as compression, decoding and editing parameters is stored in a database in correspondence with unique information (UMID). Material data (baseband signal) decoded (from compression) for editing purposes is supplemented with the unique information when transmitted. Where the material data is to be edited or re-encoded, the parameter information about the processes performed previously on the data in question is acquired from the database using the unique information as the key, so that the data is subjected to degradation-free signal processing in reference to the acquired parameter information.