A method includes receiving transform coefficients corresponding to a scaled video input signal, the scaled video input signal including a plurality of spatial layers that include a base layer. The method also includes determining a spatial rate factor based on a sample of frames from the scaled video input signal. The spatial rate factor defines a factor for bit rate allocation at each spatial layer of an encoded bit stream formed from the scaled video input signal. The spatial rate factor is represented by a difference between a rate of bits per transform coefficient of the base layer and an average rate of bits per transform coefficient. The method also includes reducing a distortion for the plurality of spatial layers by allocating a bit rate to each spatial layer based on the spatial rate factor and the sample of frames.

There is disclosed a method of encoding an input signal, the method comprising: receiving a base encoded signal, the base encoded signal being generated by feeding an encoder with a down-sampled version of an input signal; producing a first residual signal by: decoding the base encoded signal to produce a first decoded signal; and using a difference between the base decoded signal and the down-sampled version of the input signal to produce the first residual signal; producing a second residual signal by: correcting the base decoded signal using the residual signal to create a corrected decoded version; up-sampling the corrected decoded version; and using a difference between the up-sampled corrected decoded signal and the input signal to produce the second residual signal; wherein the up-sampling is one of bilinear or bicubic up-sampling. A corresponding decoding method is also disclosed.

There is disclosed a method of encoding an input signal, the method comprising: receiving a base encoded signal, the base encoded signal being generated by feeding an encoder with a down-sampled version of an input signal; producing a first residual signal by: decoding the base encoded signal to produce a first decoded signal; and using a difference between the base decoded signal and the down-sampled version of the input signal to produce the first residual signal; producing a second residual signal by: correcting the base decoded signal using the residual signal to create a corrected decoded version; up-sampling the corrected decoded version; and using a difference between the up-sampled corrected decoded signal and the input signal to produce the second residual signal; wherein the up-sampling is one of bilinear or bicubic up-sampling. A corresponding decoding method is also disclosed.

A method for video encoding includes determining a corresponding motion vector for each of multiple control points of a base predictor. The method further includes determining a corresponding motion vector difference for each of the multiple control points of the base predictor based on the determined motion vector for each respective control point. The method further includes generating prediction information of the current block to be included in a coded video bitstream. The prediction information includes (i) a usage flag indicative of the affine merge mode with offset, (ii) offset parameters defining the determined corresponding motion vector difference for each of the one or more of the control points, and (iii) a zero motion vector difference flag for the multiple control points of the base predictor. The zero motion vector difference flag indicates whether offset parameters for the respective control point are provided in the prediction information.

A method for video encoding includes determining a corresponding motion vector for each of multiple control points of a base predictor. The method further includes determining a corresponding motion vector difference for each of the multiple control points of the base predictor based on the determined motion vector for each respective control point. The method further includes generating prediction information of the current block to be included in a coded video bitstream. The prediction information includes (i) a usage flag indicative of the affine merge mode with offset, (ii) offset parameters defining the determined corresponding motion vector difference for each of the one or more of the control points, and (iii) a zero motion vector difference flag for the multiple control points of the base predictor. The zero motion vector difference flag indicates whether offset parameters for the respective control point are provided in the prediction information.

Video processing methods and apparatuses for processing a current block in a current picture by reference picture resampling include receiving input data of the current block, determining a scaling window of the current picture and a scaling window of a reference picture. The current picture and reference picture may have different scaling window sizes. A ratio between a scaling window width, height, or size of the current picture and a scaling window width, height, or size of the reference picture is constrained to be within a ratio constraint. A reference block is generated from the reference picture according to the ratio, and used to encode or decode the current block.

Embodiments of this application provide an image transmission method and apparatus. The method includes: converting a first high-resolution image into a first low-resolution image, where first resolution of the first high-resolution image is higher than second resolution of the first low-resolution image; encoding the first low-resolution image to obtain a first bitstream; obtaining a second high-resolution image, where third resolution of the second high-resolution image is higher than the second resolution, and the second high-resolution image includes high-frequency information of the first high-resolution image and excludes low-frequency information of the first high-resolution image; obtaining an image residual between the first high-resolution image and the second high-resolution image, where the image residual is used to reflect the low-frequency information of the first high-resolution image; encoding the image residual to obtain a second bitstream; and sending the first bitstream and the second bitstream.

A video decoding method according to the present invention may comprise: a step for determining whether to divide a current block into a plurality of sub-blocks; a step for determining an intra prediction mode for the current block; and a step for performing intra prediction for each sub-block on the basis of the intra prediction mode, when the current block is divided into the plurality of sub-blocks.

The embodiments relate to a method for writing, in a container file, two or more subpicture tracks; writing, in the container file, a base track, which is intended to be resolved into a video bitstream; indicating, in the base track, a layout of subpictures; writing, in the container file, a sample group description entry indicative of a first subpicture track or a group of subpicture tracks for each subpicture position in the layout of subpictures, wherein the first subpicture track includes the subpicture sequence for the respective subpicture position and wherein any track among the group of subpicture tracks includes a valid subpicture sequence for the respective subpicture position; and indicating in the container file, samples of the base track for which the sample group description entry is intended to be used for reconstructing the video bitstream. The embodiments also relate to a method for parsing, as well as technical equipment for implementing the method for writing and the method for parsing.

Several techniques for video encoding and video decoding are described. One example method includes performing a conversion between a subpicture in a video picture of a video and a bitstream of the video according to a rule. The rule specifies that, in in case a subpicture is treated as a video picture for the conversion, a cross-layer alignment restriction is applied to less than all of the multiple layers including a current layer that includes the subpicture and a subset of layers associated with the current layer.