Disclosed is an inexpensive and miniaturized digital video disc playback device having a system decoder capable of error correcting and data buffering by means of a single memory without employing separate error correcting and data buffering memories. The inventive system decoder for demodulating, error correcting, deinterleaving and descrambling of data reproduced from a disc in the digital video disc playback device, includes a memory and a memory controller for generating memory control signals for accessing the memory to record and read data when demodulating, error correcting and descrambling the reproduced data.