Patent ID: 8619872

Claim:
A method for decoding an image signal, comprising: deriving virtual position information of a virtual reference macroblock pair, by a video coding apparatus; deriving position information of a reference macroblock pair based on the virtual position information of the virtual reference macroblock pair, by the video coding apparatus, the reference macroblock pair being included in a Macroblock Adaptive Frame Field frame (MBAFF frame) of a base layer; obtaining motion information of the reference macroblock pair according to the position information of the reference macroblock pair, wherein if one macroblock in the reference macroblock pair is an intra coded macroblock and the other macroblock in the reference macroblock pair is an inter coded macroblock, motion information of the intra-coded macroblock is set using motion information of the inter-coded macroblock; predicting motion information of a target macroblock pair from the motion information of the reference macroblock pair, by the video coding apparatus, the target macroblock pair being included in a Macroblock Adaptive Frame Field frame (MBAFF frame) of an enhanced layer; and decoding the target macroblock pair using the motion information of the target macroblock pair, by the video coding apparatus, wherein the Macroblock Adaptive Frame Field frame is a frame adaptively decoded as a frame macroblock and a field macroblock, wherein the enhanced layer differs from the base layer in an aspect ratio or a spatial resolution.