Abstract: A method for motion estimation includes steps for constructing a first image segment representing a portion of present image frame and a second image segment having a plurality of image segments of an adjacent frame, comparing said plurality of image segments of said second image segment with the image signal within the first image segment, and generating a number of error values, detecting a first motion vector at one scale of resolution using the generated error values, outputting the error value associated with a reference segment pointed by the first motion vector, and the error values corresponding to the reference segment shifted by one unit of selected resolution respectively in selected direction(s), generating a second motion vector in finer scale of resolution using the output error values, and summing the first and second motion vectors.

Abstract: An apparatus for controlling a quantization step size for use in an encoder which divides one image frame into first blocks and encodes the divided first blocks and transmits the encoded data at a constant transmission rate.

Abstract: A method and apparatus for motion estimation in accordance with the present invention compares image signals of image blocks within a previous frame corresponding to a motion vector detected among error values used for detecting the motion vector of a pixel unit and surrounding image blocks which are generated by moving the reference image block to every direction per one pixel respectively with the image signal of image blocks within a present frame which the motion estimation is performed, and then generates error values according to the comparison results. By vertically comparing the generated error values, a vertical component in the motion vector of a half-pixel unit is detected. By horizontally comparing the generated error values, a horizontal component to the motion vector of a half-pixel unit is detected. Accordingly, the present invention leads to a greater efficiency to reduce the amount of data to be processed for the detection of the motion vector of a half-pixel unit.

Abstract: A variable length decoding apparatus contains a variable length code table of variable length codes which are used to decode variable length coded data and which are grouped together based on bit patterns of the variable length codes. The apparatus also includes a memory for storing the coded data in increments of N-bit data and for outputting a current N-bit data based on control signals generated in accordance with the contents of a previous N-bit data output from the memory. The apparatus also includes a controller which inputs the current N-bit data and compares the N-bit data with code state values that respectively identify the groups of the variable length codes. As a result, the controller determines the group of codes to which the current N-bit data belongs and outputs control signals based on such determination.

Abstract: A forced intra-frame coding method for a video processing system includes steps by which video data is coded in the vertical direction of a frame while coding is performed to permit production of forcibly intra-frame coded macro block lines maintaining a predetermined vertical interval. Whenever the coding for respective frames is finished, the forcibly intra-frame coded macro block lines are shifted downward by one macro block, which allows the original image to be restored relatively rapidly. Furthermore, the coding direction of macro blocks is established as the vertical direction. Vertical coding permits the amount of data for respective macro blocks to stay uniform and, thus, facilitates control of an associated transmission buffer in the video processing system.

Abstract: A method for motion estimation includes steps for comparing image signals of image blocks within a previous frame corresponding to a motion vector detected among error values used for detecting the motion vector of a pixel unit and surrounding image blocks which are generated by moving the reference image block in every direction by one pixel, respectively, with the image signal of image blocks within a present frame for which the motion estimation is performed, and then generating error values according to the comparison results. By vertically comparing the generated error values, a vertical component of the motion vector in half-pixel units is detected. By horizontally comparing the generated error values, a horizontal component of the motion vector in half-pixel units is detected. It will be appreciated that the method leads to greater efficiency in motion estimation by reducing the amount of data required to be processed during detection of the motion vector in half-pixel units.