| CPC H04N 19/91 (2014.11) [H04N 19/139 (2014.11); H04N 19/176 (2014.11); H04N 19/46 (2014.11); H04N 19/51 (2014.11); H04N 19/70 (2014.11)] | 9 Claims | 

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               1. An apparatus of decoding a video signal including a current block, the apparatus comprising: 
            a processor configured to 
                derive affine coding information of a left block and a top block of the current block, wherein the affine coding information includes an affine flag indicating whether an affine motion prediction has been performed, 
                determine a context index of the affine flag of the current block based on the affine coding information of the left block and the top block, 
                entropy-decode the affine flag of the current block based on the context index, 
                parse an affine parameter flag representing whether 4 parameters or 6 parameters are used for an affine motion model based on the affine flag of the current block, 
                obtain a motion vector predictor based on the 4 parameters or the 6 parameters being used for the affine motion model, and 
                perform a prediction for the current block based on the motion vector predictor, 
                wherein the context index of the affine flag of the current block is determined based on a sum of a value determined based on the affine flag of the left block and a value determined based on the affine flag of the top block. 
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