Video signal coding method

Abstract

In a method for encoding successive frames of a digital motion video signal in the form of compressed digital data including an intraframe coded signal and a plurality of interframe coded signals, a first frame of the digital motion video signal is encoded to form one of an intraframe coded signal and an interframe coded signal to produce a compressed digital signal; the compressed digital signal is decoded to form a decoded signal; a plurality of predicted video signal frames are produced representing a second frame of the digital motion video signal other than the first frame, at least one of the plurality of predicted video signal frames being produced with the use of the decoded signal and a motion vector representing motion between frames of the digital motion video signal; the plurality of predicted video signal frames are compared with the second frame of the digital motion video signal for producing a plurality of difference data each corresponding with a respective one of the plurality of predicted video signal frames; one of the predicted signal frames having a smallest corresponding difference data is selected; and an interframe coded signal of the compressed digital data corresponding to the selected one of the predicted video signal frames is generated.

Description

BACKGROUND OF THE INVENTIONThe present invention relates to video signal coding methods and, more particularly relates to such methods which are suitable for use in transmitting a moving picture video signal.Conventionally, in a moving picture video signal communication system, such as a conference system for a video telephone system, a moving picture video signal is transmitted to a remote point via a transmission line. It has been proposed to efficiently utilize the limited capacity of the transmission line by transmitting less than all of the successive frames of the signal according to a so-called frame skipping process. The receiver reproduces the frames that have been skipped by the transmitter by interpolation based on picture information for the frames preceding and following the skipped frames with the use of motion vectors transmitted in place of the skipped frames (refer to Japanese Patent Publication No. 60-28392).Since the motion vectors include less information than co...

AI Technical Summary

Benefits of technology

It is an object of the present invention to provide a video signal coding method which avoids the problems and disadvantages of the transmission methods described hereinabove.

It is another object of the present invention to provide a video signal coding method having the ability to transmit high quality picture data;

It is a further object of the present invention to provided a video signal coding method which produces encoded data in compressed form for efficiently utilizing the capacity of a transmission line;

Problems solved by technology

In practice, however, it is not always possible for the transmission apparatus to generate accurate motion vector information in the frame skipping process, and in the event that inaccurate motion vectors are transmitted in this fashion, the pictures reproduced by interpolation at the receiver can be objectionably poor in quality.

With the use of such apparatus, the contents of the pictures generated by interpolation at the receiver can become discontinuous in the event that the motion vectors for the transmitted unitary blocks are inaccurate and pictures reproduced with such motion vectors are likewise objectionably poor.

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