Video code and decode apparatus for snr scalability

The present invention is a video that allows, complexity is reduced to about half and applied to a device with limited resources such as available power or computational power, such as mobile communication terminals, the SNR scalability performance remains the same as conventional video decoder that of about the encoding and decoding apparatus, the coding apparatus eseuen al scalability video consisting of a base layer encoder and enhancement layer encoder for encoding the small quantization step than the quantization step of said base layer for encoding the base layer with a large quantization step in the encoder, to enter the same image data received by the said base layer encoder to the discrete cosine transformer of an enhancement layer encoder and conversion cosine discrete, subtracts the data output from the quantizer of the base layer coder in the discrete cosine transformed data and, the After the input to the quantization of the enhancement-based layer encoder, and reproduction through the inverse quantizer and an inverse discrete cosine converter for improving the output data layer coder in the quantizer, in that the reproduced signal output from the quantizer of the base layer encoder and then by summing the data stored in the frame memory, with the data and configured to perform the motion compensation for the image data received by the discrete cosine transformer of the enhancement layer encoder, the decoding apparatus includes a base layer stream and an enhanced layer stream and a variable length decoding groups, adder to the decoded enhancement layer data to the inverse quantization inverse quantizer and the inverse quantization to the data adding the base layer decoded data through a said variable length decoding for decoding the received, respectively, the adder converting the summed data through an inverse discrete cosine and clothing of high quality It characterized by configured to output the original image.