For adding additional data, such as multi-channel extension data, to base data, such as conventional stereo data, a test fingerprint of test data relating to a test time instant of the test data is provided. The test data equals the additional data or the base data or depends on the additional data or the base data in parametric manner. Using the test fingerprint, reference time instant information is determined, which depends on a reference time instant in reference data, the reference data being the conventional stereo data. Finally, the additional data or the base data is manipulated, namely using the reference time instant information and the test time instant information, to obtain manipulated data, by which synchronous reproduction of the data information can be performed. Thus, a robust and flexible possibility for synchronous, especially late extension of base data by additional data is obtained.