Residual filtering in signal enhancement coding

Abstract

According to aspects of the invention there is provided a method of encoding an input signal, the method comprising: producing a base encoded signal by feeding an encoder with a downsampled version of an input signal; producing a first residual signal by: obtaining a decoded version of the base encoded signal; and using a difference between the decoded version of the base encoded signal and the downsampled version of the input signal to produce a first residual signal; encoding the first residual signal to produce a first encoded residual signal; producing a second residual signal by: decoding the first encoded residual signal to produce a first decoded residual signal; filtering the first decoded residual signal to produce a filtered version of the first decoded residual signal; correcting the decoded version of the base encoded signal using the filtered version of the first decoded residual signal to create a corrected decoded version; upsampling the corrected decoded version; and using a difference between the corrected decoded signal and the input signal to produce the second residual signal; and encoding the second residual signal to produce a second encoded residual signal, wherein the base encoded signal, the first encoded residual signal and the second encoded residual signal comprise an encoding of the input signal. An encoder, decoder and computer readable media may also be provided.