Abstract: An image processing apparatus includes circuitry and memory coupled to the circuitry. In operation, the circuitry: derives a size of a subpicture included in a picture using a size of the picture, a position of the subpicture, and a size of a coding tree block (CTB) included in the picture, when the subpicture is located at a right border or a bottom border of the picture, the position of the subpicture being indicated using the size of the CTB; and extracts a sub-bitstream of the subpicture from a bitstream of the picture.

Abstract: An encoder includes circuitry and a memory connected to the circuitry. In operation, the circuitry: generates a plurality of predicted values of a pixel in a current picture to be encoded, using a plurality of reference pixels in the current picture, and enables or disables a process of determining a predicted value of the pixel on a block-by-block basis based on availability of at least one reference pixel among the plurality of reference pixels by filtering the plurality of predicted values based on a position of the pixel.

Abstract: An encoder includes circuitry and memory coupled to the circuitry. Given id indicating a lower temporal sublayer other than a highest temporal sublayer in temporal sublayers, the circuitry calculates a DPB output time [id] for a picture in the lower temporal sublayer. In doing so, the circuitry of the encoder subtracts a DPB output delta [id] provided for each of the temporal sublayers from a DPB output delay shared between the temporal sublayers, and given maxid indicating the highest temporal sublayer, calculates the DPB output delta [id] by subtracting a CPB removal delay [maxid] and an offset [id] from a CPB removal delay [id]. Next, the circuitry stores the offset [id] in a bitstream.

Abstract: An encoder includes circuitry and memory coupled to the circuitry. In operation, the circuitry determines whether or not a current video to be processed is a progressive video. When it is determined that the current video is a progressive video, the encoder encodes, into a bitstream, one syntax element indicating a chroma location type which is information indicating locations of chroma samples relative to luma samples for a frame included in the current video. When it is determined that the current video is not a progressive video, the encoder encodes two syntax elements into the bitstream, each of which indicates the chroma location type for a different one of fields of two types included in the current video.

Abstract: An encoder includes circuitry and memory coupled to the circuitry. In operation, the circuitry: encodes a video using (i) a decoding parameter set (DPS) which is identified based on presence of the DPS in a bitstream and (ii) a sequence parameter set (SPS) which is identified based on an identifier for the SPS.

Abstract: An encoder includes circuitry and memory. The circuitry, using the memory: derives a one-dimensional array of a plurality of reference samples for intra prediction; performs smoothing on the one-dimensional array of the plurality of reference samples which has been derived; and generates a prediction image using the plurality of reference samples. In deriving the one-dimensional array, the circuitry projects a value of at least one decoded pixel located on a first line onto a second line perpendicular to the first line, to derive at least one of the plurality of reference samples, and the smoothing is performed on the at least one decoded pixel projected onto the second line.

Abstract: An encoder includes circuitry and memory coupled to the circuitry. The circuitry: assigns a picture level slice index and a subpicture level slice index to each of the slices, the picture level slice index being assigned at a picture level, the subpicture level slice index being assigned at a subpicture level; for each of the slices, encodes the subpicture level slice index of the slice into a slice header of the slice; and encodes each of the slices into a bitstream. The picture level slice index assigned to a current slice to be processed that is included in a current subpicture to be processed is calculated by adding (i) the subpicture level slice index of the current slice and (ii) a total number of slices included in one or more subpictures that have been encoded prior to the current subpicture out of the subpictures.

Abstract: An encoder is an encoder that encodes a block in a picture using a prediction image of the block, and includes circuitry and memory. Using the memory, the circuitry: calculates a first average pixel value which is an average pixel value of first reference samples out of the first reference samples and second reference samples, The first reference samples are referable and located outside the block and adjacent to a first side of the block. The second reference samples are referable and located outside the block and adjacent to a second side of the block. When generating the prediction image, the circuitry applies the same prediction pixel value to inner samples among current samples to be processed that are included in the block. The inner samples constitute a quadrilateral region including at least two current samples in each of a horizontal direction and a vertical direction.

Abstract: An encoder includes: memory; and circuitry coupled to the memory and configured to generate an encoded bitstream. In the encoder, when a multi-layer structure is to be included in the encoded bitstream to be generated, the circuitry generates the encoded bitstream by including in the encoded bitstream (i) a sequence parameter set that refers to a video parameter set and (ii) a network abstraction layer (NAL) unit having a layer identification (ID) greater than zero in the multi-layer structure, and when the multi-layer structure is not to be included in the encoded bitstream to be generated, the circuitry generates the encoded bitstream by including in the encoded bitstream a sequence parameter set that does not refer to the video parameter set.

Abstract: A data generation method is for generating video data that covers a second luminance dynamic range wider than a first luminance dynamic range and has reproduction compatibility with a first device that does not support reproduction of video having the second luminance dynamic range and supports reproduction of video having the first luminance dynamic range, and includes: generating a video signal to be included in the video data using a second OETF; storing, into VUI in the video data, first transfer function information for identifying a first OETF to be referred to by the first device when the first device decodes the video data; and storing, into SEI in the video data, second transfer function information for identifying a second OETF to be referred to by a second device supporting reproduction of video having the second luminance dynamic range when the second device decodes the video data.

Abstract: An encoder includes circuitry and memory. The circuitry, using the memory: derives a one-dimensional array of a plurality of reference samples for intra prediction; performs smoothing on the one-dimensional array of the plurality of reference samples which has been derived; and generates a prediction image using the plurality of reference samples. In deriving the one-dimensional array, the circuitry projects a value of at least one decoded pixel located on a first line onto a second line perpendicular to the first line, to derive at least one of the plurality of reference samples, and the smoothing is performed on the at least one decoded pixel projected onto the second line.

Abstract: An encoder is an encoder that encodes a block in a picture using a prediction image of the block, and includes circuitry and memory. Using the memory, the circuitry: calculates a first average pixel value which is an average pixel value of first reference samples out of the first reference samples and second reference samples, The first reference samples are referable and located outside the block and adjacent to a first side of the block. The second reference samples are referable and located outside the block and adjacent to a second side of the block. When generating the prediction image, the circuitry applies the same prediction pixel value to inner samples among current samples to be processed that are included in the block. The inner samples constitute a quadrilateral region including at least two current samples in each of a horizontal direction and a vertical direction.

Abstract: An encoder includes memory and circuitry coupled to the memory. The circuitry is configured to: generate an encoded bitstream that includes a multi-layer structure; and store, in the encoded bitstream, a syntax element having a value indicating that a layer in the multi-layer structure to be output by a decoder is arbitrarily specified, the syntax element defining that at least one layer is to be output from among layers arbitrarily specifiable by the decoder.

Abstract: An encoder includes circuitry and memory coupled to the circuitry. In operation, the circuitry encodes, per temporal sub-layer, one or more hypothetical reference decoder (HRD) parameters into an HRD-related supplemental enhancement information (SEI) message, the one or more HRD parameters being one or more parameters for an HRD, the one or more parameters being related to a decoding unit, the HRD-related SEI message being an SEI message related to the HRD.

Abstract: A data generation method is for generating video data that covers a second luminance dynamic range wider than a first luminance dynamic range and has reproduction compatibility with a first device that does not support reproduction of video having the second luminance dynamic range and supports reproduction of video having the first luminance dynamic range, and includes: generating a video signal to be included in the video data using a second OETF; storing, into VUI in the video data, first transfer function information for identifying a first OETF to be referred to by the first device when the first device decodes the video data; and storing, into SEI in the video data, second transfer function information for identifying a second OETF to be referred to by a second device supporting reproduction of video having the second luminance dynamic range when the second device decodes the video data.

Abstract: An encoder includes circuitry and memory coupled to the circuitry. In operation, the circuitry encodes a hypothetical reference decoder (HRD) parameter into a buffering period supplemental enhancement information (SEI) message independently from a sequence parameter set. The HRD parameter is related to a decoding unit and an HRD.

Abstract: A data generation method is for generating video data that covers a second luminance dynamic range wider than a first luminance dynamic range and has reproduction compatibility with a first device that does not support reproduction of video having the second luminance dynamic range and supports reproduction of video having the first luminance dynamic range, and includes: generating a video signal to be included in the video data using a second OETF; storing, into VUI in the video data, first transfer function information for identifying a first OETF to be referred to by the first device when the first device decodes the video data; and storing, into SEI in the video data, second transfer function information for identifying a second OETF to be referred to by a second device supporting reproduction of video having the second luminance dynamic range when the second device decodes the video data.

Abstract: An encoder includes memory and circuitry coupled to the memory. The circuitry, for each of temporal sub-layers for temporal scalability different from spatial scalability, stores first parameters into buffering period supplemental enhancement information (SEI) and encodes the first parameters. The first parameters present initial delays in timing to extract data from a coded picture buffer (CPB). The circuitry stores a second parameter into the buffering period SEI and encodes the second parameter. The second parameter indicates a total number of the temporal sub-layers. A value of the second parameter is equal to a value of a third parameter that is encoded into a sequence parameter set and indicates a total number of the temporal sub-layers.

Abstract: An encoder includes memory and circuitry coupled to the memory. The circuitry stores a total number of temporal sub-layers in a bitstream into either a picture timing supplemental enhancement information (SEI) message or a buffering period SEI message, and encodes the total number of the temporal sub-layers.

Abstract: Circuitry of a decoder is configured to decode an image according to a coding structure including an intra random access point (IRAP) picture, leading pictures to be output before the IRAP picture in output order, and trailing pictures to be output after the IRAP picture in the output order. When the image is decoded, the circuitry decodes, according to a flag in a bitstream, at most one trailing picture among the trailing pictures before decoding the leading pictures in decoding order, and decodes the trailing pictures other than the at most one trailing picture after decoding the leading pictures in the decoding order. The flag indicates whether a picture of each of access units in the bitstream is a field picture. The circuitry decodes the at most one trailing picture before decoding the leading pictures in the decoding order when the flag indicates that the picture is a field picture.