A method for ascertaining at least one first predetermined data unit (D1, D2, D3, D4) to be indicated at an exploiter of rights related to at least one predetermined first piece of music, including the steps of: a) providing a data source; b) first examination if at least one predetermined metadata unit (M1, M2, M3) associated with the at least one first piece of music can be ascertained based on the data source; c) establishing a communicative link to a database, which respectively provides at least one second predetermined data unit (D1, D2, D3, D4) related to respective second pieces of music for a plurality of the second pieces of music, wherein at least one second information (M1, M2, M3, M4) is respectively associated with the second pieces of music; d) if the first examination in b) yields that the at least one predetermined metadata unit (M1, M2, M3) can be ascertained, ascertaining the at least one predetermined metadata unit (M1, M2, M3) and second examination if at least one of the second pieces of music is identifiable with the at least one first piece of music, wherein the second examination is effected based on a comparison of the at least one metadata unit (M1, M2, M3) of the at least one first piece of music to the at least one second information (M1, M2, M3, M4) of the respective second pieces of music; e) if the second examination in d) yields that at least one of the second pieces of music is identifiable with the at least one first piece of music, providing the second predetermined data unit (D1, D2, D3, D4) of the second piece of music identifiable with the at least one first piece of music as the predetermined data unit (D1, D2, D3, D4) to be indicated at the exploiter of rights related to the first piece of music; characterized in that an application program, in which the at least one first piece of music was used, and/or a file, which contains a reference to the at least one first piece of music used in an application program is provided as the data source. a) providing a data source; b) first examination if at least one predetermined metadata unit (M1, M2, M3) associated with the at least one first piece of music can be ascertained based on the data source; c) establishing a communicative link to a database, which respectively provides at least one second predetermined data unit (D1, D2, D3, D4) related to respective second pieces of music for a plurality of the second pieces of music, wherein at least one second information (M1, M2, M3, M4) is respectively associated with the second pieces of music; d) if the first examination in b) yields that the at least one predetermined metadata unit (M1, M2, M3) can be ascertained, ascertaining the at least one predetermined metadata unit (M1, M2, M3) and second examination if at least one of the second pieces of music is identifiable with the at least one first piece of music, wherein the second examination is effected based on a comparison of the at least one metadata unit (M1, M2, M3) of the at least one first piece of music to the at least one second information (M1, M2, M3, M4) of the respective second pieces of music; e) if the second examination in d) yields that at least one of the second pieces of music is identifiable with the at least one first piece of music, providing the second predetermined data unit (D1, D2, D3, D4) of the second piece of music identifiable with the at least one first piece of music as the predetermined data unit (D1, D2, D3, D4) to be indicated at the exploiter of rights related to the first piece of music;