Abstract: For picture decoding and encoding of neural-network-based bitstreams, a picture is represented by an input set of samples which is obtained from the bitstream. The picture is reconstructed from output subsets, which are generated as a result of processing the input set L. The input set is divided into multiple input subsets Li. The input subsets are each subject to processing with a neural network having one or more layers. The neural network uses as input multiple samples of an input subset and generates one sample of an output subset. By combining the output subsets, the picture is reconstructed. In particular, the size of at least one input subset is smaller than a size that is required to obtain the size of the respective output subset, after processing by the one or more layers of the neural network.

Abstract: The present disclosure relates to methods and apparatuses for decoding data for (still or video processing into a bitstream). Two or more sets of segmentation information elements are obtained from the bitstream. Then, each of the two or more sets of segmentation information elements are inputted respectively into two or more segmentation information processing layers out of a plurality of cascaded layers. In each of the two or more segmentation information processing layers, the respective sets of segmentation information are processed. The decoded data for picture or video processing are obtained based on the segmentation information processed by the plurality of cascaded layers. Accordingly, the data may be decoded from the bitstream in an efficient manner in the layered structure.

Abstract: The present disclosure relates to picture or video encoding and decoding. A picture portion includes a luma component and a chroma component with a resolution lower than a resolution of the luma component. To obtain matching resolution of the luma component and the chroma component, a selection is performed between a down-sampling processing of the luma component and an up-sampling processing of the chroma component. Then, the selected processing is applied to a picture portion. The bitstream is then generated based on the selected processing, and includes encoding the processed picture portion. The selection between chroma up-sampling and luma down-sampling enables adaption of the input picture portion for the desired application. For example, some applications may aim at reducing complexity or bitrate in which case the luma down-sampling may be more favorable, whereas other application may aim at higher quality in which case chroma up-sampling may be more favorable.

Abstract: A method of coding implemented by a decoding device or an encoding device, comprising obtaining indication information for a luma position (cbWidth/2, cbHeight/2) of a current coding block, relative to a top-left luma sample position (xCb, yCb) of the current coding block; setting a value of a luma intra prediction mode associated with the current coding block to a first default value, when the indication information indicates that an Intra Block Copy (IBC) mode or palette mode is applied for the luma component at the luma position (cbWidth/2, cbHeight/2), relative to the top-left luma sample position (xCb, yCb) of the current coding block; and obtaining a value of a chroma intra prediction mode based on the value of the luma intra prediction mode of the current coding block.

Abstract: The present disclosure relates to video encoding and decoding, and in particular to determining motion information for a current block using a history-based motion vector predictor, HMVP, list. The HMVP list is constructed, with said list being an ordered list of N HMVP candidates Hk, k=0, . . . , N?1, which are associated with motion information of N preceding blocks of the frame and precede the current block. Each HMVP candidate has motion information including elements of one or more motion vectors, MVs, one or more reference picture indices corresponding to the MVs, and one or more bi-prediction weight indices. One or more HMVP candidates from the HMVP list are added into a motion information candidate list for the current block; and the motion information is derived based on the motion information candidate list.

Abstract: A method of decoding of a picture from a video bitstream is disclosed. The video bitstream includes a slice header of a current slice and data representing the current slice. The method comprises: obtaining a parameter used to derive a number of tiles in the current slice from the slice header when a slice address of the current slice is not an address of a last tile in the picture where the current slice located; and reconstructing the current slice using the number of tiles in the current slice and the data representing the current slice.

Abstract: A method for deblocking a chroma block edge between a first chroma block of a first image block and a second chroma block of a second image block. The method includes a decision process which includes: determining a first chroma quantization parameter for the first chroma block based on a first luma quantization parameter of a first luma block of the first image block and a chroma QP mapping table for the first chroma block; determining a second chroma quantization parameter for the second chroma block based on a second luma quantization parameter of a second luma block of the second image block and a chroma QP mapping table for the second chroma block; determining an averaged and rounded chroma quantization parameter based on the first chroma quantization parameter and the second chroma quantization parameter; and determining a threshold parameter based on the averaged and rounded chroma quantization parameter.

Abstract: The present disclosure relates to efficient signaling of feature map information for a system employing a neural network. In particular, at the decoder side, a presence indicator is obtained based on information parsed from a bitstream. Based on the value of the obtained presence indicator, further data related to a feature map region are parsed or the parsing is bypassed. The presence indicator may be, for instance, a region presence indicator indicating whether feature map data is included in the bitstream or may be a side information presence indicator indicating whether a side information related to the feature map data is included in the bitstream. Similarly, an encoding method, as well as encoding and decoding devices, are provided. Accordingly, feature map data may be processed more efficiently, by reducing decoding complexity, and the amount of transmitted data can be reduced by applying the bypassing.

Abstract: A method of decoding of a picture from a video bitstream is disclosed. The video bitstream includes a slice header of a current slice and data representing the current slice. The method comprises: obtaining a parameter used to derive a number of tiles in the current slice from the slice header when a slice address of the current slice is not an address of a last tile in the picture where the current slice located; and reconstructing the current slice using the number of tiles in the current slice and the data representing the current slice.

Abstract: A method of coding is implemented by a decoding device, the method includes: receiving a bitstream, and obtaining from the bitstream, a first luma bit depth value of luma samples of a current picture. The method also includes performing a Hadamard Transform Domain Filtering (HTDF) post reconstruction filtering of a block of the current picture by using a lookup table based on the obtained first luma bit depth value.

Abstract: Signalling of syntax elements in a sequence parameter set of a video bitstream is addressed. Particularly, it is provided a method of decoding a video bitstream wherein a sequence parameter set, SPS, is coded that contains syntax elements that apply to a video sequence, the method comprising obtaining a value of a first syntax element from the SPS used to specify whether a decoded picture buffer, DPB, parameters syntax structure is present in the SPS and obtaining a value of a second syntax element from the SPS, at least when determining that the value of the first syntax element specifies that the DPB parameters syntax structure is present in the SPS, used to specify the presence of a DPB syntax element in the DPB parameters syntax structure, wherein the DPB syntax element is applied to a temporal sublayer except for the highest temporal sublayer in the video sequence.

Abstract: This application provides an image dynamic range processing method and apparatus. The method includes: obtaining a first coordinate value of a first interpolation point and a first coordinate value of a third interpolation point related to a first cubic spline curve; and determining, based on histogram information of a first luminance interval of a to-be-processed image, a first coordinate value of a second interpolation point related to the first cubic spline curve. The first luminance interval is an interval between the first coordinate value of the first interpolation point and the first coordinate value of the third interpolation point. The first coordinate value of the first interpolation point, the first coordinate value of the second interpolation point, and the first coordinate value of the third interpolation point are used to determine a function of the first cubic spline curve.

Abstract: Methods and apparatuses are provided for estimating motion vectors of a dense motion field based on subsampled sparse motion field. The sparse motion field includes two or more motion vectors with their respective start positions. For each of the motion vectors, a transformation is derived which transforms the motion vector from its start point into a target point. The transformed motion vectors then contribute to the estimated motion vector on the target position. The contribution of each motion vector is weighted. Such motion estimation may be readily used for video encoding and decoding.

Abstract: A method of coding implemented by a decoding device, comprising obtaining a bitstream; obtaining a value of an indicator for a current block according to the bitstream; obtaining a value of a first parameter for the current block and a value of a second parameter for the current block, according to the value of the indicator and a predefined lookup table; obtaining a value of a sample distance for a sample which is located in the current block, according to the value of the first parameter and the value of the second parameter; obtaining a prediction value for the sample, according to the value of the sample distance for the sample.

Abstract: The present disclosure relates to pre-processing of video images. In particular, the video images are pre-processed in an object-based manner, i.e., by applying different pre-processing to different objects detected in the image. Moreover, the pre-processing is applied to a group of images. As such, object detection is performed in a plurality of images and the pre-processing for the plurality of images may be adapted to the decoded images and is applied to the decoded images.

Abstract: The present disclosure relates to image modification such as an image enhancement. The image enhancement may be applied for any image modification and it may be applied during or after image encoding and/or decoding, e.g. as a loop filter or a post filter. In particular, the image modification includes a multi-channel processing in which a primary channel is processed separately and secondary channels are processed based on the processed primary channel. The processing is based on a neural network. In order to enhance the image modification performance, prior to applying the modification, the image channels are analyzed and a primary channel and the secondary channels are determined, which may vary for multiples of images, images or image areas.

Abstract: The present disclosure relates to methods and apparatuses for modifying a quantizer. In particular, within a preliminary set of quantization levels, at least one quantization level is modified based on optimization involving distortion for a predetermined set of input values. At least one another quantization level out of the preliminary set is not modified. The not modified (non-modifiable) quantization level is the minimum clipping value or the maximum clipping value. The modification may facilitate increasing the dynamic range of the quantized/inverse-quantized data. Such modified quantizer may be advantageous for employment in neural networks to compress their data such as feature maps or the like. It may improve accuracy of the neural network.

Abstract: A method of coding implemented is provided. The method includes the following operations: obtained the height and width of a prediction block without applying clipping operation; calculating a value of a vertical component of an intra prediction sample based on the height and width of the prediction block; calculating a value of a horizontal component of the intra prediction sample based on the height and width of the prediction block; and generating the intra prediction sample based on the value of the vertical component and the value of the horizon component.

Abstract: A method comprising: signaling a set of low-level indicators for a predicted block, wherein each of the indicators of the set enables or disables an intra prediction smoothing mechanism for the predicted block; signaling a first set of high-level indicators on a slice-level or a higher level, wherein each of the high-level indicators of the first set determines signaling for an intra prediction smoothing mechanism which is enabled or disabled by an indicator of the set of low-level indicators; and signaling a second set of high-level indicators, wherein each of the high-level indicators of the second set determines the presence of at least one of the corresponding high-level indicators of the first set, and wherein the values of corresponding high-level indicators of the first set are inferred to be zero when the value signaled by high-level indicator of the second set is zero.

Abstract: A system and method of decoding of a video or picture bitstream implemented by a decoding device are described. The bitstream can include data representing a current video coding layer. Furthermore, when determining that the current video coding layer is the only one layer in the bitstream, the method can include using the identifier of a NAL unit of the current video coding layer as the identifier of the current video coding layer.