| CPC H04N 23/698 (2023.01) [G06T 3/40 (2013.01); H04N 19/103 (2014.11); H04N 19/11 (2014.11); H04N 19/119 (2014.11); H04N 19/124 (2014.11); H04N 19/129 (2014.11); H04N 19/13 (2014.11); H04N 19/134 (2014.11); H04N 19/159 (2014.11); H04N 19/174 (2014.11); H04N 19/176 (2014.11); H04N 19/44 (2014.11); H04N 19/51 (2014.11); H04N 19/625 (2014.11); H04N 19/45 (2014.11)] | 7 Claims | 

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               1. A method for decoding a 360-degree image, the method comprising: 
            receiving a bitstream in which the 360-degree image is encoded, the bitstream including data of an extended 2-dimensional image, the extended 2-dimensional image including a 2-dimensional image and a predetermined extension region, and the 2-dimensional image being from an image with a 3-dimensional projection structure and including one or more faces; 
                generating a prediction image by referring to syntax information obtained from the received bitstream; 
                obtaining a decoded image by adding the generated prediction image to a residual image, the residual image being obtained by inverse-quantizing and inverse transforming quantized transform coefficients from the bitstream; and 
                reconstructing the decoded image into the 360-degree image according to a projection format, 
                wherein the projection format is selectively determined based on identification information, among a plurality of pre-defined projection formats including an ERP format in which the 360-degree image is projected in a two-dimensional plane or a CMP format in which the 360-degree image is projected in a cube, 
                wherein a size of the extension region is variably determined based on at least one of first information indicating a width on a left side of the extension region or second information indicating a width on a right side of the extension region, independently of a size of the 2-dimensional image, 
                wherein the extension region is not included in the image with the 3-dimensional projection structure, and 
                wherein at least one of the identification information, the first information or the second information is obtained from the bitstream. 
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