operations as those described above the buffer memories 9 and 10 operate in pairs more specifically while a signal read out from the hard disk apparatus 8 is written onto one of the buffer memories 9 or 10 the other buffer memory 10 or 9 reads out a signal which has been supplied from the hard disk apparatus 8 and stored in the buffer memory 10 or 9 at a rate of the video signal and then supplies the signal to the mpeg1 decoder 12 via the second switch 11 portion j of fig4 represents an input to the mpeg1 decoder 12 as shown in fig4 the input has been extended so as to have the same period as that of the output in portion a and is continuously reproduced as shown in fig4 for recording and reproducing a video signal simultaneously and continuously the period of each of the signals a 1 a 2 a 3 is set to be longer than the following time t t seek time for preparing to record data onto the hard disk time required for writing the data having the period onto the hard disk seek time for preparing to reproduce the data from the hard disk time required for reading out the data having the period from the hard disk if the total of these times becomes longer than the period of a 1 a 2 a 3 then the video cannot be recorded but overflows thus the period is required to be sufficiently longer than the.