Abstract: A video decoding apparatus including a memory for storing at least first and second reference pictures, a prediction signal forming circuit for forming a prediction signal to produce an output signal, using a first reference signal designated by a first motion vector for the first reference picture and a second reference signal designated by a second motion vector for the second reference picture read out of the memory. Also included is a decoding circuit for decoding the transmitted first motion vector and a transmitted motion vector difference, and for further decoding the second motion vector by adding a scaled motion vector and the motion vector difference. The scaled motion vector is derived by scaling the first motion vector to a motion vector for the second reference picture. Further included is a decoding circuit for decoding a transmitted difference signal and for obtaining the output signal by adding the difference signal and the prediction signal.

Abstract: A video coding apparatus comprises a memory for storing a coded picture signal used as a reference picture signal, a vector detecting circuit for detecting, from plural field picture signals or plural frame picture signals which are read out from the memory and the reference picture signals, an optimum motion vector regarding a picture to be coded, a prediction signal producing circuit for subjecting a spatial-temporal filtering to a reference picture designated by the optimum motion vector to produce a prediction signal, and a coding circuit for coding the to-be-coded picture signal on the basis of the prediction signal.

Abstract: A method of detecting a motion vector in an image coding apparatus, including blocking an input image block to be coded into a plurality of input blocks each consisting of a plurality of pixels; sub-sampling a coded image signal to obtain a coded and sub-sampled image signal; sub-sampling the input image block at a predetermined pixel interval to obtain a sub-sampled input block; searching a primary block most correlated with the sub-sampled input block from the coded and sub-sampled image signal in a predetermined range, to output a primary motion vector which indicates the primary block most correlated with the sub-sampled input blocks; and controlling at least one of a central position of a searching area and a searching pel accuracy in accordance with a type of the primary motion vector, to search a secondary block most correlated with one of the input blocks from a coded image signal, to obtain a secondary motion vector.

Abstract: A video coding apparatus comprises a memory for storing a coded picture signal used as a reference picture signal, a vector detecting circuit for detecting, from plural field picture signals or plural frame picture signals which are read out from the memory and the reference picture signals, an optimum motion vector regarding a picture to be coded, a prediction signal producing circuit for subjecting a spatial-temporal filtering to a reference picture designated by the optimum motion vector to produce a prediction signal, and a coding circuit for coding the to-be-coded picture signal on the basis of the prediction signal.

Abstract: A coding apparatus for coding symbolized information signals includes a coding unit for assigning fixed-length code words to a plurality of information symbol strings consisting of at least one type of a given number of information symbols and coding the information signals on the basis of this assignment, a control information adding unit for adding control information containing information for performing predetermined processing to the code words, and a transmitting/recording unit including at least one of a unit for transmitting and a unit for recording the code words added with the control information.