The invention provides an image encoding and decoding method, encoding and decoding device, and encoder and decoder. The image decoding method comprises: analyzing a video bitstream to obtain from an image and/or a segmentation layer data unit of the video bitstream, a reshaping parameter, determining, according to the obtained reshaping parameter, a reshaping parameter for recovering an image; and reshaping, according to the reshaping parameter for recovering the image, the image to be recovered; wherein the image to be recovered is an image obtained from a decoded video bitstream prior to the reshaping step; the image and/or the segmentation layer data unit comprises at least one of the following data units: an image and/or segmentation layer parameter set different from an picture parameter set, a parameter data unit included in an access unit (AU) corresponding to the image to be recovered, segmentation header information, and a system layer picture parameter data unit. The invention resolves problems of
