US 5,475,430 AGranted

Direct encoding system of composite video signal using inter-frame motion compensation

AssigneeKokusai Denshin Denwa Kabushiki Kaisha

InventorsTakahiro Hamada, Shuichi Matsumoto

Life of this patent

Estimating the term…

Loading patent…

Abstract

Direct encoding of composite video signal which includes both luminance signal (Y) and chrominance signal (C) is carried out without separating luminance signal from chrominance signal. A motion of a block in a frame (8) which provides a motion vector (MV.sub.x, MV.sub.y), and a from a preceding frame is detected in a motion detector reference block is defined in said preceding frame which is locally decoded according to said motion vector. A block to be encoded in a current frame is converted through Hadamard conversion H (1). A composite motion compensation (7) provides a prediction block according to said reference block, which is subject to phase compensation of color sub-carrier, according to remainder of the value MV.sub.x +MV.sub.y when said value is divided by 4assuming that sampling frequency of video signal is four times as high as color sub-carrier frequency. The difference (9) of each element between output matrix of said Hadamard conversion (1) and matrix of said prediction block is quantized (2) and encloded (3). The encoded output is transmitted together with said motion vector. Thus, composite video signal is encoded directly signal, and excellent signal quality with high compression ratio is obtained.

(1) Direct Encoding System of Composite video using inter-frame motion compensation comprising;

an input terminal for receiving a block of input composite video signal which includes both luminance signal (Y) and chrominance signal (C) modulated with color sub-carrier signal, said block being a part of video frame, and having a plurality of pels,
a first Hadamard converter coupled with said input terminal for effecting Hadamard conversion for each block in said input composite video signal,
a subtractor for providing difference between each element of matrix of output of said first Hadamard converter and each related element of matrix of a prediction block,
a quantizer for quantizing output of said subtractor,
a first encoder for encoding output of said quantizer,
an inverse quantizer coupled with output of said quantizer,
an adder coupled with output of said inverse quantizer for providing sum of said output and said prediction block,
a second Hadamard converter coupled with output of said adder for providing inverse Hadamard conversion,
a frame memory coupled with output of said second Hadamard converter to store a frame of locally decoded video signal,
a motion detector coupled with said input terminal through a luminance separation circuit, and output of said frame memory through a luminance separation circuit to provide motion vector (MV.sub.x, MV.sub.y) of each block between a current frame and a preceding frame,
a composite motion compensator having at least a third Hadamard conversion unit, and a phase compensation circuit, coupled with output of said motion detector, and output of said frame memory, to determine a reference block in a preceding frame according to said motion vector (MV.sub.x, MV.sub.y), to carry out Hadamard conversion to said reference block, to effect phase compensation of color sub-carrier of said Hadamard converted reference block, so that the phase compensated reference block is applied to said subtractor as said prediction block,
a second encoder for encoding said motion vector,
a multiplexer for multiplexing outputs of said first encoder and said second encoder, and
an output terminal coupled with output of said multiplexer to provide encoded video signal.

11 more elements

Abstract

Claims6