Abstract: An in-loop filtering procedure for improving the picture quality of a reconstructed image (video) can be performed. The in-loop filtering procedure can be also performed on a picture divided into sub pictures. According to embodiments of the present document, sub picture-related information and in-loop filtering-related information can be efficiently signaled.

Abstract: A method by which a video decoding device decodes a video, according to the present document, can comprise the steps of: parsing, from a bitstream, number information related to the number of slices of which the height within a tile of a current picture is explicitly signaled; parsing, from the bitstream, on the basis of the number information, height information related to the height of the slices of which the height is explicitly signaled; deriving the number of slices in the tile on the basis of the number information and the height information; generating prediction samples by predicting the current block of the current picture on the basis of the slices within the tile; generating reconstructed samples on the basis of the prediction samples; and generating a reconstructed picture for the current picture on the basis of the reconstructed samples.

Abstract: An image decoding method performed by a decoding device according to the present disclosure comprises the steps of: obtaining prediction-related information and indication information comprising a first flag which indicates whether or not a sample adaptive offset (SAO) process to be applied to a current block is applied at a picture level or a slice level; parsing information related to the SAO process from a picture header or a slice header on the basis of the first flag; generating prediction samples for the current block on the basis of the prediction-related information; generating reconstructed samples for the current block on the basis of the prediction samples; and performing the SAO process for the reconstructed samples on the basis of the information related to the SAO process.

Abstract: According to the disclosure of the present document, a decoded picture buffer (DPB) may be updated on the basis of DPB-related information. The DPB-related information may include a syntax element related to a maximum required size of the DPB. In updating the DPB, a bumping process may be invoked on the basis of a case where a first condition, in which the number of pictures in the DPB is neither greater than nor equal to a value obtained by adding 1 to a value of the syntax element related to the maximum required size of the DPB, is satisfied.

Abstract: A video decoding method performed by a video decoding apparatus, according to the present document, comprises: parsing number information about the number of slices of which heights are explicitly signaled in a tile of a current picture from a bitstream; parsing height information about the heights of slices of which heights are explicitly signaled from the bitstream based on the number information; deriving the number of slices in the tile based on the number information and the height information; and decoding the current picture based on the slices in the tile, wherein the height information includes the same number of syntax elements as a value of the number information, and based on the value of the number information being n, the heights of a 0th slice to an n?1th slice in the tile may be derived based on the syntax elements.

Abstract: An image decoding method according to the present invention comprises the steps of: acquiring information to form a reference picture set of a current picture by entropy decoding the received bitstream information; and performing prediction on a prediction block inside the current picture by using a reference picture list which is formed based on the reference picture set.

Abstract: According to embodiments of the present document, information for carrying out in-loop filtering across virtual boundaries can be efficiently signaled. For example, in-loop filtering can be carried out on the basis of signaling of information which is related to whether in-loop filtering across virtual boundaries is enabled or not.

Abstract: According to a disclosure of the present document, information/parameter related to splitting of a picture can be signaled on the basis of a no-picture partition flag, information related to a tile, and information related to a slice, unnecessary redundant signaling can be removed accordingly, and the number of bits assigned to the signaling can be reduced, thereby deriving an effect of increasing an overall coding efficiency.

Abstract: A method by which a decoding device decodes an image, according to the present document, comprises the steps of: acquiring image information including decoded picture buffer (DPB) parameter information and an output layer set (OLS) DPB parameter index for a target OLS; deriving the DPB parameter information about the target OLS on the basis of the OLS DPB parameter index; updating a DPB on the basis of the DPB parameter information about the target OLS; and decoding the current picture on the basis of the updated DPB.

Abstract: According to embodiment(s) of the present document, multilayer-based coding can be performed. The multilayer-based coding can include a sub-bitstream extraction process. Inputs of the sub-bitstream extraction process can include a value related toa target OLS index and a value related to a highest temporal identifier.

Abstract: An image decoding method performed by a decoding apparatus according to the present document comprises the steps of: acquiring a flag indicating whether a picture header (PH) network abstraction layer (NAL) unit exists; acquiring a PH on the basis of the flag; and decoding a current picture related to the PH on the basis of the PH.

Abstract: According to embodiments of the present document, a zero-order exponential Golomb coding scheme (ue(v)) is used for a parsing procedure of an information/syntax element related to luma/chroma ALF filter coefficient absolute values, so that operational overhead and complexity can be reduced. In addition, since the range of values of the information related to the luma/chroma ALF filter coefficient absolute values is fixed, coding that uses ue(v) can be efficiently performed.

Abstract: A video decoding method can comprise the steps of: acquiring image information from a bitstream, the image information including a picture header related to a current picture, and the current picture including a plurality of slices; parsing, from the picture header, a first flag indicating whether information necessary for an inter prediction operation is in the picture header and/or a second flag indicating whether information necessary for an intra prediction operation is in the picture header; parsing, from the picture header, the information necessary for the inter prediction operation and/or the information necessary for the intra prediction operation based on the first flag and/or the second flag; and generating prediction samples based on the information necessary for the inter prediction operation and/or the information necessary for the intra prediction operation.

Abstract: The present invention relates to a video encoding method, a video decoding method, and a device using the same, and the video encoding method according to the present invention comprises the steps of: specifying a tile and a slice by partitioning an inputted picture; performing encoding on the basis of the tile and the slice; and transmitting the encoded video information, wherein the picture is partitioned into one or more tiles and one or more slices, and the restrictions for parallel processing can be applied to the tiles and the slices.

Abstract: A decoding method performed by a decoding apparatus, according to embodiments of the present document, may comprise the steps of: acquiring, via a bitstream, image information including residual information; generating reconstructed samples of a current picture on the basis of the residual information; and generating modified reconstructed samples by performing an in-loop filtering procedure on the reconstructed samples of the current picture, wherein whether or not the in-loop filtering procedure is performed across virtual boundaries is determined. The virtual boundaries can bring, to the decoding apparatus, advantages from a hardware perspective.

Abstract: A video decoding method performed by a video decoding apparatus, according to the present document, comprises the steps of: obtaining image information from a bitstream, wherein the image information includes a picture header associated with a current picture, and the current picture includes a plurality of slices; parsing at least one of a first flag and a second flag from the picture header; generating prediction samples by performing at least one of intra prediction and inter prediction on a current block in the current picture on the basis of at least one of the first flag and the second flag; generating reconstructed samples on the basis of the prediction samples; and generating a reconstructed picture on the basis of the reconstructed samples.

Abstract: A (decoded) picture may be split into subpictures/tiles. Information on the subpictures may be obtained by a decoding device, and a decoding procedure may be performed on the basis of the information on the subpictures. In addition, information on the tiles may be obtained by a decoding device, and a decoding procedure may be performed on the basis of the information on the tiles. According to embodiments of the present document, subpicture-related information and tile-related information can be efficiently signaled, and an in-loop filtering procedure can be performed on the basis of the subpicture-related information.

Abstract: A video decoding method performed by a video decoding device according to the present document comprises the steps of: acquiring image information from a bitstream, the image information including a picture header associated with the current picture including a plurality of slices; parsing, from the picture header, a first flag indicating whether information necessary for an inter-prediction operation for a decoding process is present in the picture header; parsing, from the picture header, a second flag indicating whether information necessary for an intra-prediction operation for the decoding process is present in the picture header; and generating prediction samples by performing at least one of intra-prediction or inter-prediction for the slices in the current picture on the basis of the first flag or the second flag.

Abstract: In a method for decoding an image by a decoding apparatus according to the present disclosure, a current picture is configured to include a single slice, on the basis of a flag indicating whether information on a subpicture exists and a flag indicating whether the subpicture includes a single slice.

Abstract: According to embodiment(s) of the present document, computational overhead and complexity can be reduced by using a 0th-order exponential Golomb coding scheme (ue(v)) for procedures of parsing syntax elements/information about absolute values of luma/chroma ALF filter coefficients. In addition, coding using ue(v) can be efficiently performed by fixing the range of values of the information about the absolute values of the luma/chroma ALF filter coefficients.