Moving image signal encoding apparatus and decoding apparatus

Abstract

A moving image signal encoding apparatus includes: a frame decimating circuit for extracting . .encoded.!. frames from an input moving image signal at specified intervals; a frame interpolating circuit for obtaining an interpolated frame between the . .encoded.!. .Iadd.extracted .Iaddend.frames, and a circuit for obtaining an error formed by frame interpolation. A moving image signal decoding apparatus includes: a receiving circuit for extracting a frame code from an inputted signal; a frame decoding circuit for decoding the frame code to obtain a reproduced frame, and a frame interpolating circuit for obtaining an interpolated frame between the reproduced frames. By transmitting an error of the interpolated frame from the encoding apparatus to the decoding apparatus and correcting the error of the interpolated frame with the decoding apparatus, the error of the interpolated frame is eliminated. Alternatively, depending on the value of the error of the interpolated frame obtained with the encoding apparatus, a circuit determines the operation mode as to whether the frame interpolating circuit of the decoder carries out frame interpolation or preceding value holding and sends a flag to show the operation mode to the decoder, so that improvement occurs when the error of the interpolated frame is large.

What is claimed is: 
     
       1. A moving image signal encoding apparatus comprising: a frame decimator for extracting . .the encoded.!. frame from an input moving image signal at specified intervals; a frame encoder for encoding said . .encoded.!. frames .Iadd.extracted by said decimator .Iaddend.to obtain frame codes; a frame interpolator for producing interpolated frames positioned between said . .encoded.!. .Iadd.extracted .Iaddend.frames from said frame codes; an error evaluator for evaluating errors of said interpolated frames, and a transmitter for transmitting said frame codes and output signals of said error evaluator as an output of the moving image signal encoding apparatus. 
     
     
       2. A moving image signal encoding apparatus comprising: a frame decimator for extracting . .encoded.!. frames .Iadd.from an input moving image signal at specified intervals; a frame encoder for encoding said frames extracted by said decimator .Iaddend.to obtain frame codes; a decoder for decoding said frame codes to obtain reproduced frames; a frame interpolator for producing interpolated frames positioned between said reproduced frames; . .and.!. .Iadd.an .Iaddend.interpolated frame encoder for encoding errors of said interpolated frames to obtain interpolated frame codes. .,.!..Iadd.; .Iaddend.and a transmitter for transmitting said frame codes and said interpolated frame codes .Iadd.as an output of the moving image signal encoding apparatus.Iaddend.. 
     
     
       3. A moving image signal encoding apparatus according to claim 2, wherein said decoder includes a means for decoding . .the.!. .Iadd.each of said .Iaddend.frame . .code.!. .Iadd.codes .Iaddend.to obtain a reproduced frame, and a means for obtaining a predicted frame .Iadd.from said reproduced frame.Iaddend., and .Iadd.wherein .Iaddend.said encoder comprises a subtractor for obtaining a predicted error signal from said . .encoded.!. .Iadd.extracted .Iaddend.frame and said predicted frame, and a predicted error encoder for encoding said predicted error signal to obtain a frame code. 
     
     
       4. A moving image signal encoding apparatus according to claim 2, wherein said interpolated frame encoder includes a subtractor for obtaining a difference between said interpolated frame and a corresponding frame of said input moving image signal, and an error encoder for encoding said difference to obtain an interpolated frame code. 
     
     
       5. A moving image signal encoding apparatus according to claim 2, wherein said interpolated frame encoder includes: a subtractor for obtaining a difference between said interpolated frame and a corresponding frame of said input moving image signal; an error calculator for obtaining a value of said difference; an encoded area selector for determining an area for encoding said difference by an output of said error calculator, and an encoder for encoding said difference by using an output of said encoded area selector to obtain an interpolated frame code. 
     
     
       6. A moving image signal encoding apparatus according to claim 2, further comprising a motion estimator for detecting a motion vector of the input moving image signal, wherein said decoder includes a means for decoding . .the.!. .Iadd.each of said .Iaddend.frame . .code.!. .Iadd.codes .Iaddend.to obtain a reproduced frame, and a means for motion compensating said reproduced frame by said motion vector to obtain a predicted frame, and .Iadd.wherein .Iaddend.said encoder includes a subtractor for obtaining a predicted error signal from said . .encoded.!. .Iadd.extracted .Iaddend.frame and said predicted frame, and a predicted error encoder for encoding said predicted error to obtain a frame code. 
     
     
       7. A moving image signal decoding apparatus for decoding a signal . .produced by a moving image signal encoding apparatus comprising: a frame decimator for extracting encoded frames from an input moving image signal at specified intervals; a frame encoder for encoding said encoded frames to obtain frame codes; a decoder for decoding said frame codes to obtain reproduced frames, a frame interpolator for producing interpolated frames positioned between said reproduced frames; an interpolated frame encoder for encoding errors of said interpolated frames to obtain interpolated frame codes, and a transmitter for transmitting said frame codes and said interpolated frame codes;.!. .Iadd.containing frame codes which have been produced by encoding frames extracted from a moving image signal at specified intervals and interpolated frame codes which have been produced by encoding errors of interpolated frames positioned between the extract frames; .Iaddend.said decoding apparatus comprising: a receiver for extracting said frame . .code.!. .Iadd.codes .Iaddend.and said interpolated frame . .code.!. .Iadd.codes .Iaddend.from an input signal; a decoder for decoding said frame . .code.!. .Iadd.codes .Iaddend.to obtain . .the.!. reproduced . .frame.!. .Iadd.frames.Iaddend.; a frame interpolator for producing the interpolated . .frame.!. .Iadd.frames .Iaddend.positioned between said reproduced frames; an error corrector for correcting an error of .Iadd.each of .Iaddend.said interpolated . .frame.!. .Iadd.frames.Iaddend., and a means for producing a moving image signal from said reproduced . .frame.!. .Iadd.frames .Iaddend.and an output of said error corrector. 
     
     
       8. A moving image signal encoding apparatus comprising: a frame decimator for extracting . .encoded.!. frames from an input moving signal at specified intervals; a motion estimator for obtaining motion vectors between said . .encoded.!. .Iadd.extracted .Iaddend.frames; a frame encoder for encoding said . .encoded.!. .Iadd.extracted .Iaddend.frames to obtain frame codes; a frame interpolator for producing interpolated frames positioned between said . .encoded.!. .Iadd.extracted .Iaddend.frames from said frame codes; . .a.!..Iadd.an .Iaddend.error calculator for obtaining errors of said interpolated frames; a selector for selecting whether to output said . .motor.!. .Iadd.motion .Iaddend.vectors or to output a flag to indicate not to output said motion vectors by using the errors obtained by said error calculator, and a means for outputting said frame codes and an output of said selector. 
     
     
       9. A moving image signal decoding apparatus for decoding . .the.!. .Iadd.a .Iaddend.signal . .produced by a moving image signal encoding apparatus comprising: a frame decimator for extracting encoded frames from an input moving image signal at specified intervals; a motion estimator for obtaining motion vectors between said encoded frames; a frame encoder for encoding said encoded frames to obtain frame codes; a frame interpolator for producing interpolated frames positioned between said encoded frames from said frame codes; an error calculator for obtaining errors of said interpolated frames; a selector for selecting whether to output said motion vectors or the output a flag to indicate not to output said motion vectors by using the errors obtained by said error calculator, a means for outputting said frame codes and an output of said selector.!. .Iadd.containing frame codes which have been produced by encoding frames extracted from a moving image signal at specified intervals and interpolated frame codes which have been produced by encoding errors of interpolated frames positioned between the extracted frames and one of either a motion vector between said extracted frames and a flag indicating the absence of a motion vector between said extracted frames.Iaddend.; said decoding apparatus comprising: a receiver for extracting the frame codes and said interpolated frame codes from an inputted signal; a frame decoder for decoding said frame codes to obtain reproduced frames, and a frame interpolator for producing .Iadd.an .Iaddend.interpolated . .frames.!. .Iadd.frame .Iaddend.positioned between said reproduced frames or holding a preceding reproduced frame, wherein, when said receiver outputs . .a.!. .Iadd.said .Iaddend.motion vector, said frame interpolator produces . .an.!. .Iadd.said .Iaddend.interpolated frame, and when said receiver receives . .a.!. .Iadd.said .Iaddend.flag, said frame interpolator holds the preceding reproduced frame.