DECODING DEVICE CAPABLE OF FORWARDLY AND BACKWARDLY REPRODUCING PICTURES WITH A HIGH QUALITY

摘要

In a decoding device for decoding an input signal into a decoded signal, a delay circuit delays the decoded signal into a delayed signal with a delay equal to a frame period of a digital video signal which is encoded into an encoded signal by interframe predictive encoding. A forward filter of a predetermined filtering characteristic filters the delayed signal into a first filtered signal. An adder adds the input signal to the first filtered signal to produce an added signal. A subtracter subtracts the input signal from the delayed signal to produce a subtracted signal. An inverse filter filters the subtracted signal into a second filtered signal. Responsive to a mode signal, a selector selects one of the added and the second filtered signals to produce, as the decoded signal, the added and the second filtered signals when the mode signal indicates that the input signal is produced in a forward direction from a leading part to a trailing part of the encoded signal and when the mode signal indicates that the input signal is produced in a backward direction reversed relative to the forward direction, respectively. Another inverse filter may be inserted between the delaying circuit and the subtracter. In this case, the subtracter and the second filter are replaced in position with each other.