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The delay time is dependent on the number of picture elements included inside a block. The video signal is supplied from the delay circuit 2a to a subtractor 2b. Here the distinction between the image sign, and the prediction sign supplied via a line 105a branching from an output line 105 of a prediction sign generator 5, is produced, and the distinction, i.e. the prediction error signal, is then supplied to a quantizer 3 which features to restrict the number of potential levels.

Where the transmission path has a high transmission speed in order that it is attainable to assign a quantity of bits to one picture element on an average, the movement vector information occupies only a useful reference portion of the entire thing of information transmitted. However, where the transmission pace is low, the movement vector info occupies a considerable portion of the entirety of knowledge transmitted, for instance, more than 50%. An example of the movement vector information measured close to an precise image image, is talked about in a Hirano et al paper entitled "Investigation regarding the Block Size in the movement compensated inter-frame Coding", lecture No. 697 presented before the general assembly of the Institute of Electronics and Communication Engineers of Japan, communication section, 1980. According to this paper, the entropy of motion vector utilized as a measure of the movement vector info is about zero.1 bit/picture component where a block constituted by a plurality of picture components has a dimension of four lines×8 picture elements.

Generally speaking, a function that makes smallest the prediction error is outlined as the optimum operate. Consequently, the motion compensation inter-frame prediction system could also be thought-about as an adaptive prediction coding system which adaptably determines a most adaptive prediction function among many prediction features.

Therefore, the reproduced picture signal is reworked by the scan inverter circuit 14 back to the video signal in authentic time series, then the decoded video sign is sent out on line 214. 10 is a block diagram displaying an embodiment of the predictive decoding system in accordance with the current invention. In the figure, the video sign which has been coded by prediction by means of the predictive coding system of FIG.

A motion included within the television sign is mostly assumed to be a parallel movement, and realization of high coding efficiency for shifting pictures has been tried by performing inter-frame prediction in consideration of the quantity of shift of a picture between contiguous frames. Such an approach is called movement compensation inter-frame prediction.

The sum of these two code lengths is taken into account to be an amount of data generated when the particular prediction perform is used. With regard to the other prediction functions, the sum of two code lengths is equally determined. A prediction perform which is obtained when the results of comparability of the sum of the 2 code lengths exhibits a minimal is set as an optimum prediction function, that is, a motion vector. It is possible to make smaller the amount of the transmission info when the motion vector is decided in this method than when the movement vector is determined by using solely the prediction error information as within the prior artwork. The share of the codes necessary to characterize this motion vector with respect to all of the transmission info varies significantly relying upon the transmission pace at the transmission path used.

For the predictive coding system using motion compensation, the range of correction, i.e., the variety of vectors N, ought to preferably be as giant as potential and the number of picture parts in a block be as small as attainable. From this viewpoint, the method of look at this by which essential hardware is set by the value of N and a broad variety of movement compensation disadvantageously wants an increased hardware. In distinction, the strategy of primarily uses M arithmetic items repeatedly for N occasions, and the hardware requirement navigate to this website is virtually decided by the worth of M. Thus, it can be seen that the strategy of is extra advantageous. The tackle of the prediction signal generator memory 8-11a for writing the above-mentioned supplementary image elements is preferably next to the addresses for storing image components which are needed for determining the optimum prediction function find more info for the present block, for facilitating read/write management. For this function, A1 by way of A8 are written following the addresses for storing x1 by way of x16 as proven in FIG. The necessary storage capacity of the prediction signal generator memory 8-11a is expressed, utilizing symbols k, L, m and n, as (2m+k)×(2n+L) for figuring out the optimum prediction function of the present block, k×(2n+L) for supplementary picture elements for determining the optimum prediction operate of the following block, amounting to 2(m+k)×(2n+L) in total.