Apparatus, a method and a computer program for video coding and decoding

Abstract

A method comprising: deriving a first prediction block () at least partly based on an output of a neural net () using a first set of parameters; deriving a first encoded prediction error block (-) through encoding a difference of the first prediction block and a first input block; encoding () the first encoded prediction error block into a bitstream; deriving a first reconstructed prediction error block () from the first encoded prediction error block; deriving a training signal () from one or both of the first encoded prediction error block and/or the first reconstructed prediction error block (); retraining () the neural net () with the training signal () to obtain a second set of parameters for the neural net (); deriving a second prediction block () at least partly based on an output of the neural net using the second set of parameters; deriving a second encoded prediction error block (-) through encoding a difference of the second prediction block and a second input block; and encoding () the second encoded prediction error block into a bitstream. The invention relates to image or video encoding or decoding, especially by online training a neural network () that is in the prediction loop.