PURPOSE: To prevent the perfect dubbing of the contents of a record disk, by reproducing selectively just a part of the recorded sound channels.

CONSTITUTION: The 1st language stereo is selected by the 1st and 2nd channels when the multiplex stereo mode information is recorded to a video disk. Under such conditions, a switch 23 is controlled so as to select the output of a wave detector 21. At the same time, a switching circuit 28 has a control to turn on switches S1 and S3 and turn off switches S2 and S4 respectively. The main channel signal L+R is extracted out of the stereo information by an LPF24. While the subchannel signal L-R is extracted out of a BPF25 and undergoes FM wave detection through a wave detector 27. As a result, the left-right channel stereo signals of the 1st language are extracted out of a matrix circuit 36. While the 2nd language stereo produced by the 3rd and 4th channels is selected by having a control to select the output of a wave detector 22 by the switch 23.