Signal coding apparatus and method, signal recording medium, and signal transmitting method

A signal coding method, comprising the steps of:

• effecting an inter-coding in which a motion is predicted between frames of an input motion-picture signal, a resulted prediction residual signal is decomposed into blocks and each block is subjected to an orthogonal transform such as DCT, effecting an intra-coding in which an input motion-picture image signal is directly decomposed into blocks and of the blocks is subjected to an orthogonal transform;
• judging the orthogonal transform in which the block is to be formed from frames or fields;
• and
• controlling the method of judging, based on the decided type of orthogonal transform, whether the input picture image signal is to be intra- or inter-coded.

A signal recoding medium for recording coded signals, wherein the signals have been coded by:

• effecting an inter-coding in which a motion is predicted between frames of an input motion-picture signal, a resulted prediction residual signal is decomposed into blocks and each block is subjected to an orthogonal transform including DCT,
• effecting an intra-coding in which an input motion-picture image signal is directly decomposed into blocks and of the blocks is subjected to an orthogonal transform;
• and
• the coding is controlled by judging whether the input motion-picture signal is intra- or inter-coded based on a result of judgement of whether the block is composed of frames or fields in an orthogonal transform.

A signal transmitting method, comprising the steps of:

• effecting an inter-coding in which a motion is predicated between frames of an input picture image signal, a resulted prediction residual signal is decomposed into blocks and each of the blocks is subjected to an orthogonal transform including DCT;
• effecting an intra-coding in which an input picture image signal is directly decomposed into blocks and each of the blocks is subjected to an orthogonal transform;
• judging the type of orthogonal transform in which the block is to be formed from frames or fields;
• controlling the method of judging, based on the decided type of orthogonal transform, whether the input picture image signal is to be intra- or inter-coded;
• and
• transmitting a coded data thus produced.