Matsushita Electric Industrial Co., Ltd.

Satoshi Matsuya

Akiyoshi Tanaka

Wataru Fujikawa

Atsushi Nagata

Ikuo Inoue

Hiroyuki Uwabo

A motion compensated prediction interframe coding system which first measures characteristics regarding the fineness of a pattern or texture of a picture, which is represented by an input television signal and is divided into a group of continuous blocks each quantized by using a quantization step size, and changes the quantization step size into a smaller one if quantizes a block having a picture pattern or texture finer than patterns of the other blocks. Thereby, an amount of generated codes can be limited but a motion compensated prediction frame coding operation can be performed without degrading the fineness of the texture of the original input picture.

Motion compensated prediction interframe coding system

A motion compensated prediction interframe coding system which includes a first checking portion for judging whether a motion compensation of a coding block is effective and outputting a motion compensation control signal representing the result of the judgement, a storage portion for storing motion vectors of the coding block and adjacent blocks and the motion compensation control signal, a second checking portion for comparing the motion vector of the coding block, of which the motion compensation should be effected, with each of the motion vectors of the adjacent blocks, of which the motion compensation should be effected, and judging that the intra-loop filtering processing to be performed after the motion compensation is ineffective if the number of the adjacent blocks, of which the motion vectors are identical with that of the coding block, is equal to or more than a predetermined number and that the filtering processing performed after the motion compensation is effective in another case, a motion-compensated brightness calculating portion for calculating motion-compensated brightness of pixels of the blocks, of which the motion compensation is effected, and a predictive brightness calculating portion for calculating predictive brightness of the pixels of the blocks by performing the filtering processing of the motion-compensated brightness of the pixels only if the filtering processing is effective. Thereby, the amount of the generated prediction error signals are reduced, and the picture quality is improved.

An apparatus for coding a moving-picture signal comprises a first memory temporarily memorizing an input picture signal of one frame. A block of the picture signal, which corresponds to a central portion of the frame, is firstly read out from the first memory and then other blocks of the picture signal are sequentially read out from the first memory in a predetermined order. Each of the blocks of the picture signal has a predetermined number of adjacent pixels. A transform device transforms each block of the picture signal read out from the first memory into transmission information. A second memory stores the transmission information and has a capacity which adaptively varies with a position of the block relative to the frame. A quantizer adaptively quantizes an output from the transform device in accordance with a quantity of the transmission information stored in the second memory and with the position of the block relative to the frame.

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Sagamihara, Japan

Satoshi Matsuya