Abstract: Quantization interval determining method and circuit are provided. The quantization interval determining circuit has a quantizer matrix calculator, a macroblock classifier, a reference quantization interval storage, a block classifier, a bit table storage, a histogram calculator, a frame bit generation predictor, a reference quantization interval adjuster, a target bit allocator, and a bit rate controller. In the quantization interval determining method and circuit, a video signal is classified based on human visual sense characteristics, a reference quantization interval suited for each class is determined, a target bit is adaptively allocated, considering distribution of the video signal, to determine a quantization interval compatible with a given transmission speed, simultaneously with the reference quantization interval determination, and then a final quantization interval is determined.

Abstract: A method and apparatus for coding an image for reducing the amount of bit generation. Those are realized by eliminating a perceptual error from a predict error, which is generated in performing a differential pulse coded modulation (DPCM) procedure with respect to a movement between moving pictures, by using a look up table (LUT) defined for human perceptual color tolerance in the YUV chromatic domain.

Abstract: A decoding signal error concealment system for concealing data which are determined as errors during the process of decoding coded image data into signals in a digital VTR system including an error correction decoder, a block data selecting unit a block data decoding unit, an address and control signal generating unit, a line memory unit and a filtering data selecting unit. The system substitutes error data with image data of the preceding frame when reproducing image data which includes error data, thus enabling substitution of image data including chrominance signals, and prevents boundary effects of the substituted image data.