Inter-frame predictive encoding system with encoded and transmitted prediction error

Abstract

In an inter-frame predictive encoding system, reference frames are set. The reference frames are separated at equal intervals. The reference frames are selected from successively inputted frames of a video signal. Each of the reference frames is encoded. A prediction signal for a dependent frame between the reference frames is generated on the basis of a signal of the reference frames which precedes and follows the dependent frame respectively. A signal of the dependent frame is generated on the basis of the prediction signal corresponding thereto. An error of the predicting of the signal of the dependent frame is encoded. .Iadd.A complementary decoding system reconstructs the video signal from the encoded reference frames and the encoded error. .Iaddend.

What is claimed is: 
     
       1. An inter-frame predictive encoding system comprising: means for separating successively-inputted frames of a video signal into reference frames and dependent frames, the reference frames being spaced at predetermined intervals, the dependent frames situated between the reference frames;   means for encoding display information of the reference frames;   means for predicting display information of each dependent frame on the basis of display information of reference frames which precede and follow said dependent frame respectively;   means for generating an error between the predicted display information and corresponding actual display information of said dependent frame; and   means for encoding said error.   
     
     
       2. The inter-frame predictive encoding system of claim 1 wherein said predicting means comprises means for multiplying the two dimensional position of the preceding reference frame by a first predetermined weight coefficient; means for multiplying the display information of the following reference frame by a second predetermined weight coefficient; and means for predicting the display information of the dependent frame on the basis of a resultant of said multiplication between the display information and the first weight coefficient and a resultant of said multiplication between the display information and the second weight coefficient. 
     
     
       3. In an inter-frame predictive encoding system comprising means for performing motion-compensated inter-frame prediction using motion vectors between successively inputted frames of a video signal; the improvement comprising: means for setting specified frames separated at equal intervals, the specified frames being selected from successively inputted frames of a video signal;   means for detecting motion vectors between the specified frames;   means for detecting motion vectors between .[.adjacent.]. .Iadd.a .Iaddend.non-specified .[.frames.]. .Iadd.frame located .Iaddend.between the specified frames .Iadd.and the specified frames .Iaddend.as differences with respect to said motion vectors between the specified frames.   
     
     
       4. An inter-frame predictive encoding system as recited in claim 3 further comprising: means for generating a prediction signal for a non-specified frame between the specified frames on the basis of a signal of the specified frames which precede and follow the non-specified frame respectively;   means for generating a prediction error representing a difference between the prediction signal and a signal of the non-specified frame corresponding thereto;   encoding means for encoding said prediction error; and   means for outputting and transmitting encoded data which are generated by the encoding in the encoding means.   
     
     
       5. An inter-frame predictive encoding system comprising: means for setting reference frames separated at equal intervals, the reference frames being selected from successively inputted frames of a video signal;   first encoding means for encoding each of the reference frames;   means for generating a prediction signal for a dependent frame between the reference frames on the basis of a signal of the reference frames which precede and follow the dependent frame respectively;   means for generating a prediction error representing a difference between the prediction signal and a signal of the dependent frame corresponding thereto;   second encoding means for encoding said prediction error; and   means for outputting and transmitting encoded data which are generated by the encoding in the first encoding means and the second encoding means. .Iadd.   
     
     
       6.  A decoding system for decoding video signals encoded by the system of claim 1, said decoding system comprising: decoding means for receiving and decoding the encoded display information of said reference frames and said encoded error, each of said decoded reference frames producing an output which corresponds to the display information for said reference frame;   prediction signal generating means for reconstructing said predicted display information for each dependent frame based upon the two reference frames which respectively precede and follow said dependent frame;   means for combining said error and said predicted display information for said dependent frame; and   means for outputting the display information for each reference and dependent frame in proper sequence to produce a video signal. .Iaddend. .Iadd.7. A decoding system for decoding video signals that have been encoded in an encoder by arranging said video signals into spaced-apart reference frames and dependent frames located therebetween; said display information of said reference frames being out from said encoder in encoded form and used therein to predict the display information for said dependent frames, said encoder generating and outputting a prediction error signal for each dependent frame corresponding to the difference between the predicted and actual display information for each dependent frame, said decoding system comprising:   decoding means for receiving and decoding each of the encoded reference frames and the prediction error signal for each of the dependent frames; and   processing means for reconstructing the display information for each dependent frame from the corresponding prediction error signal and the reference frames which precede and follow said dependent frame. .Iaddend. .Iadd.8. The decoding system in accordance with claim 7 including means for outputting the display information for said reference frames and said dependent frames in proper sequence. .Iaddend. .Iadd.9. The decoding system in accordance with claim 7, wherein said processing means includes   memory means for storing the display information of said two reference frames which respectively precede and follow said dependent frame;   means for combining weighted values of said display information for said two reference frames to generate predicted display information for said dependent frame; and   means for combining the predicted display information and the prediction error signal for each dependent frame to reconstruct the display information for each dependent frame. .Iaddend. .Iadd.10. The decoding system in accordance with claim 9, wherein said weighted values are generated by multiplying said display information by weighting coefficients selected such that the reference frame temporally closer to the dependent frame is given a greater weight. .Iaddend. .Iadd.11. The decoding system in accordance with claim 9, wherein said weighted values are generated by multiplying said display information by weighting coefficients that are selected to be linearly related to the temporal position of said dependent frame relative to the two reference frames on either side thereof. .Iaddend. .Iadd.12. The decoding system in accordance with claim 9, wherein said processing means further includes means for calculating motion vectors representative of image movement between said two reference frames and means for calculating motion-compensated predicted display information for each of said dependent frames located between said two reference frames from said motion vectors and the display information of said reference frames. .Iaddend. .Iadd.13. A method for decoding video signals that have been encoded in an encoder by arranging said video signals into spaced-apart reference frames and dependent frames located therebetween, said display information of said reference frames being output from said encoder in encoded form and used therein to predict the display information for said dependent frames, said encoder generating and outputting a prediction error signal for each dependent frame corresponding to the difference between the predicted and actual display information for each dependent frame, said method comprising the steps of:   (a) receiving and decoding each of the encoded reference frames and the prediction error signal for each of the dependent frames;   (b) reconstructing the display information for each dependent frame from the corresponding prediction error signal and the reference frames which precede and follow said dependent frame; and   (c) outputting the display information for said reference frames and said dependent frames in proper sequence to generate a video signal. .Iaddend. .Iadd.14. The method in accordance with claim 13 wherein step (b) includes the steps of;   storing the display information of said two reference frames which respectively precede and follow each dependent frame;   combining weighted values of said display information for said two reference frames to generate predicted display information for said dependent frame; and   combining the predicted display information and the prediction error signal for each dependent frame to reconstruct the display information for each   
     
     
        dependent frame. .Iaddend. .Iadd.15.  The method in accordance with claim 14 wherein said weighted values are generated by multiplying said display information for said two reference frames by weighting coefficients selected such that the reference frame temporally closer to the dependent frame is given a greater weight. .Iaddend. .Iadd.16. The method in accordance with claim 13, wherein step (b) includes the steps of; calculating motion vectors representative of image movement between said two reference frames; and   calculating motion-compensated predicted display information for each of said dependent frames located between said two frames from said motion vectors and the display information of said two reference frames. .Iaddend.