Method and apparatus for encoding/decoding video signal by using graph-based separable transform

A method for decoding a video signal based on a graph-based separable transform (GBST), the method comprising:

• extracting a residual signal from the video signal;
• performing an inverse-transform for the residual signal based on the GBST;
• and
• generating a reconstruction signal by adding the inverse-transformed residual signal to a prediction signal,
• wherein the GBST represents a transform generated based on line graphs, which are obtained by a Gaussian Markov Random Field (GMRF) modelling of a row and a column of the residual signal.

An apparatus for decoding a video signal based on a graph-based separable transform (GBST), the apparatus comprising:

• a parsing unit configured to extract a residual signal from the video signal;
• an inverse transform unit configured to perform inverse transform on the residual signal based on the GBST;
• and
• a reconstruction unit configured to generate a reconstruction signal by adding the inverse-transformed residual signal and a prediction signal,
• wherein the GBST corresponds to a transform generated based on line graphs which are obtained by GMRF modeling of rows and columns of the residual signal.