Abstract: Video encoder and decoder, provided with a motion compensator for motion-compensated video coding or decoding in which a picture is coded or decoded in blocks in alternately horizontal and vertical steps. The motion compensator is provided with addressing means (160) and controlled multiplexers (111-119) for refreshing a search area memory (101-109) at each step, in conformity with the direction of the step.

Abstract: A motion detector, particularly for use in a television system for transmitting television pictures in a digital form, is adapted to partition each picture into pixel blocks, to subject each pixel block to a modified intraframe transform for determining a first coefficient which corresponds to the basic picture having the lowest horizontal and highest vertical frequency, and to determine a plurality of further coefficients which correspond to basic pictures also having the lowest horizontal frequency, but a vertical frequency which is lower than that for the first coefficient. The motion detector signalizes the presence of motion within a pixel block if the first coefficient has a large absolute value, but if simultaneously none of the further coefficients has a sufficiently large absolute value. If the first coefficient has a sufficiently large absolute value, absence of motion is nevertheless signalized if simultaneously one of the further coefficients also has a sufficiently large absolute value.

Abstract: A damping material (19) is provided on one of the two side faces (7, 8), of a magnetic head having two plate shaped ferrite core limbs (3, 4). The material consists of a synthetic resin filled with less than 30% by volume of filler having a density of more than 10.times.10.sup.3 kg/m.sup.3. The filler is at least 74% by weight of the damping material and the density of the damping material is larger than 4.times.10.sup.3 kg/m.sup.3 and its modulus of elasticity ranges between 10.sup.7 and 10.sup.9 Pa.