Abstract: An apparatus is provided to reduce the memory capacity required to hold the data of a search area when motion vector detection is conducted in a wider area by using a plurality of motion vector detecting circuits. A motion vector detecting device includes an object pixel memory, reference pixel memory, motion vector detecting circuits, and a vector selecting circuit. Data of different blocks are provided to each of motion vector detecting circuits from the object pixel memory. Data of common search areas are simultaneously provided to the motion vector detecting circuits from the reference pixel memory. Output from each of the motion vector detecting circuits is processed by the vector selecting circuit to provide a motion vector in a search area which is wider than the search area of each motion vector.

Abstract: In a motion-vector detecting device for detecting motion-vectors of images processed through a two-dimensional filter by a subsampling method, a filter circuit must process pixel values at a block boundary by delaying the pixel value in both horizontal and vertical directions, which complicates reading pixel data from memory and increases the size of the filter circuit. The present invention provides a motion-vector detecting device for detecting motion-vectors by searching a match of a coding block of a coding image with a prediction candidate-block in a searching area of a reference image.

Abstract: The invention is directed to provide a code-amount control device for use in video-coding device, which controls the generated code-amount of each block (block length) after variable-length coding in the video-coding process to surely be less than the designated target code-amount. The code amount control device is provided with a rate control circuit for setting a target code-amount of each of blocks to be encoded, a rounding circuit for converting a sequence of quantized values into a set of the number of continuous zeroes and following thereto non-zero quantized values and a code-length table containing variable code-length values to be allocated to respective sets of the number of continuous zeroes and non-zero values.

Abstract: A motion image coding apparatus providing enhanced image quality as compared with the prior art includes a coding unit for coding first, second and third frames, a prediction efficiency calculating circuit for calculating prediction efficiency in inter-frame prediction, in coding by the coding unit using said first or second frame as a reference frame, and a reference frame interval determining circuit for determining a reference frame interval which is a time interval between the first and second frames, time interval between the second frames and time interval between the first frames.