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 circuitry, and memory coupled to the circuitry. The circuitry, in operation, for each of a plurality of sub-bitstreams having mutually different frame rates, encodes identification information into a header of a bitstream including the plurality of sub-bitstreams, the identification information indicating a temporal ID that is an identifier of a temporal layer related to a temporal scalability and corresponds to the sub-bitstream, and encodes level information indicating a conformance level of the sub-bitstream.

Abstract: An encoder includes: circuitry; and memory coupled to the circuitry. In operation, the circuitry: controls whether to change a resolution of a picture from a resolution of a previous picture preceding the picture in one of display order and encoding order, according to a constraint that allows the changing only when the picture is a random access picture among one or more random access pictures; and when a resolution of a reference picture to be used in encoding of an inter-predicted picture is different from a resolution of the inter-predicted picture, resamples a reference image in the reference picture according to a difference between the resolution of the reference picture and the resolution of the inter-predicted picture, and encodes an image in the inter-predicted picture using the reference image resampled.

Abstract: A decoding method includes: decoding, from a bitstream, cropping information indicating an amount of cropping corresponding to an amount of padding of a first subpicture that is a subpicture (i) which is among a plurality of subpictures constituting a picture, (ii) in which at least one end of the subpicture is included in at least one end of the picture, (iii) to which at least one subpicture is adjacent on a side opposite to the at least one end of the subpicture, and (iv) which is padded so that a size of the subpicture reaches an integer multiple of a preconfigured coding unit size in at least one direction; decoding the first subpicture from the bitstream; and cropping the first subpicture according to the amount of cropping.

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. 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: 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: 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: writes, into a sequence parameter set which is header information of a sequence, video usability information syntax which is information for realizing an additional function in display of an image, and syntax different from the video usability information syntax. The syntax includes at least one parameter related to display timing of the image.

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 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: A reproduction apparatus includes circuitry and memory coupled to the circuitry. In operation, the circuitry: obtains a first segment including first subpictures corresponding to points of time and a second segment including second subpictures corresponding to the points of time; combines the first subpictures and the second subpictures to generate access units corresponding to the points of time; and reproduces the access units generated.

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 circuitry and memory coupled to the circuitry. In operation, the circuitry: writes, into a sequence parameter set which is header information of a sequence, video usability information syntax which is information for realizing an additional function in display of an image, and syntax different from the video usability information syntax. The syntax includes at least one parameter related to display timing of the image.

Abstract: An encoder includes circuitry, and memory coupled to the circuitry. The circuitry, in operation, for each of a plurality of sub-bitstreams having mutually different frame rates, encodes identification information into a header of a bitstream including the plurality of sub-bitstreams, the identification information indicating a temporal ID that is an identifier of a temporal layer related to a temporal scalability and corresponds to the sub-bitstream, and encodes level information indicating a conformance level of the sub-bitstream.

Abstract: An encoder includes circuitry and memory coupled to the circuitry. In operation, in the case where a video parameter set is used for encoding a video, the circuitry writes a first parameter into the video parameter set. The first parameter indicates the maximum number of one or more temporal sublayers in a layer set unit. The circuitry writes a second parameter into a sequence parameter set. The second parameter indicates the maximum number of one or more temporal sublayers in a sequence unit. In the case where the video parameter set is used for encoding the video, the second parameter is limited to less than or equal to the first parameter. In the case where the video parameter set is not used for encoding the video, the second parameter is limited to less than or equal to a fixed value.

Abstract: An encoder includes circuitry and memory coupled to circuitry. In operation, circuitry: designs each of subpictures included in a picture in such a manner that at least one pixel included in the subpicture is included in a conformance cropping window; encodes arrangement information indicating an arrangement of each of the subpictures; and encodes each of the subpictures.

Abstract: An encoder includes circuitry, and memory coupled to the circuitry. The circuitry, in operation, for each of a plurality of sub-bitstreams having mutually different frame rates, encodes identification information into a header of a bitstream including the plurality of sub-bitstreams, the identification information indicating a temporal ID that is an identifier of a temporal layer related to a temporal scalability and corresponds to the sub-bitstream, and encodes level information indicating a conformance level of the sub-bitstream.

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.