Abstract: In known differential encoder and decoder systems, a number of processing steps within a scanning clock must be performed in the differential pulse code modulator at one location in a time-critical loop, namely a summation, a multiplication with addition, a subtraction and a quantization. For the case, which practically always occurs, particularly in picture processing, where a number of signals not used for the prediction sample is located between the signals used for the prediction sample, a solution is provided in which only a translation and an addition are required within the time-critical loop. Such an arrangement corresponds to a special split-up of the equation for the prediction error signal in single terms. The solution provided can be modified in different manners so as to economize on elaborate components, and can also be used for adaptive modulators. The same measures can also be used in the demodulator.

Abstract: A known method of generating intermediate pictures is based on an assumed linear interpolation of the positional change of corresponding objects in successive reference pictures. Such intermediate pictures, however, do not correspond to real pictures, notably when the reference pictures originate from a sensor moves along a curved path. In accordance with the invention the assignment of corresponding object points in successive reference pictures is subdivided so that the resultant assignment, starting from one reference picture, can be repeatedly performed on the successive intermediate pictures so that ultimately the next reference picture is obtained. Such an assignment algorithm produces faithful intermediate pictures also when the sensor is moved along a curved path.