A method and an apparatus for encoding a picture and decoding a bitstream representing a matrix using a neural network is provided. The method includes obtaining a resizing method out of a plurality of resizing methods. The resizing method is applied to resize an input of size S to a size S. The resized input is processed by the neural network, wherein the neural network comprises one or more downsampling layers. Subsequently, the method provides an output of the neural network, the output having a size P that is smaller than S in the at least one dimension