A blank for disc is heat treated for adjusting a surface hardness thereof to not less than Hv700. The delivery roller is activated in a state where the first detection sensor detects the sheet on the sheet supply tray while the second detection sensor does not detect the leading end portion of the sheet on the sheet supply tray. A modified composition may also contain dimethyl sulfoxide and a terpene solvent. The rocking element includes an upper end and a lower end. The first device then displays the user interface as defined by the data. When encoding, a downmixed audio signal, first additional information for restoring multi-channel audio signals from the downmixed audio signal, and second additional information representing characteristics of a residual signal are multiplexed.