Image decoding device and image encoding device for adaptive quantization and inverse quantization, and method performed thereby

Abstract

An image decoding method includes obtaining, second feature data from a bitstream for first feature data of a current image, obtaining quantization data and probability data by applying the second feature data to a neural network, modifying the probability data, based on sample values of the quantization data, obtaining quantized first feature data by applying entropy decoding, based on the modified probability data, on bits included in the bitstream, obtaining dequantized first feature data by dequantizing the quantized first feature data based on the sample values of the quantization data, and reconstructing the current image by performing neural network-based decoding on the dequantized first feature data. The first feature data having been obtained by performing neural network-based encoding on the current image.