Image data encoding / decoding method and apparatus

Abstract

The present invention provides an image data encoding / decoding method and apparatus that improves compression performance. [Solution] The 360-degree image decoding method includes the steps of: generating a predicted image by referring to syntactic information obtained from a received bitstream; obtaining a decoded image by combining the generated predicted image with a residual image obtained by inverse quantization and inverse transformation of the bitstream; reconstructing the decoded image into a 360-degree image in a projection format; obtaining a group of motion vector candidates, including the motion vector of a block adjacent to the current block to be decoded, from the motion information contained in the syntactic information; deriving a predicted motion vector from the group of motion vector candidates based on selection information extracted from the motion information; and determining the predicted block of the current block to be decoded using the final motion vector derived by adding the predicted motion vector with the difference motion vector extracted from the motion information.

Claims

1. A method for decoding 360-degree images, The step of receiving a bitstream in which the 360-degree image has been encoded, The process involves generating a predicted image by referring to syntactic information obtained from the received bitstream, The steps include: combining the generated predicted image with the residual image obtained by inverse quantization and inverse transformation of the bitstream to obtain a decoded image; The steps include: reconstructing the decoded image into a 360-degree image using a projection format; The step of generating the aforementioned predicted image is: The steps include obtaining a group of motion vector candidates from the motion information contained in the syntactic information, which includes the motion vectors of blocks adjacent to the current block to be decoded, The steps include: deriving a predicted motion vector from a group of motion vector candidates based on the selected information extracted from the aforementioned motion information; A method for decoding a 360-degree image, comprising the step of determining the predicted block of the current block to be decoded using a final motion vector derived by adding the predicted motion vector with the difference motion vector extracted from the motion information.

2. The aforementioned group of motion vector candidates is If a block adjacent to the current block is on a different surface from the surface to which the current block belongs, A method for decoding a 360-degree image according to claim 1, wherein the method consists only of motion vectors for blocks belonging to surfaces that have image continuity with the surface to which the current block belongs, among the adjacent blocks.

3. The aforementioned adjacent blocks are, The method for decoding a 360-degree image according to claim 1, wherein the block is adjacent to the current block in at least one of the directions of upper left, top, upper right, left, and lower left.

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