CN-121986479-A - Methods, apparatuses and computer program products for video encoding and decoding

Abstract

Embodiments relate to an apparatus comprising means for processing an image to predict a block from prediction samples of two prediction blocks, determining when two of the two prediction blocks of the block are within a boundary of the image and applying bi-prediction based on the two prediction blocks of the block to obtain bi-prediction blocks, determining when one of the two prediction blocks is at least partially outside the boundary of the image and applying uni-prediction based on the prediction blocks within the boundary of the image to obtain uni-prediction blocks, deriving filter coefficients based on a selected set of samples of the bi-prediction blocks, wherein the selected set of samples comprises samples that have been downsampled in the bi-prediction blocks according to a downsampling method, and filtering at least a portion of the uni-prediction blocks according to the filter coefficients.

Inventors

• P. Astola
• J. Renema

Assignees

• 诺基亚技术有限公司

Dates

Publication Date

20260505

Application Date

20240820

Priority Date

20231011

Claims (20)

1. 1. An apparatus for encoding, comprising: Means for processing an image to predict a block from prediction samples of two prediction blocks; means for determining when two of the two prediction blocks of the block are within a boundary of the picture, and means for applying bi-prediction based on the two prediction blocks of the block to obtain a bi-predicted block; means for determining when one of the two prediction blocks is at least partially outside the boundary of the image, and means for applying unidirectional prediction based on the prediction blocks within the image boundary to obtain unidirectional prediction blocks; Means for deriving filter coefficients based on a selected set of samples of the bi-predictive block, wherein the selected set of samples comprises samples that have been downsampled in the bi-predictive block according to a downsampling method, and Means for filtering at least a portion of the unidirectional prediction block according to the filter coefficients to generate a filtered unidirectional prediction block.
2. 2. The device of claim 1, wherein the downsampling method comprises selecting uniformly spaced samples within the bi-predictive block having a predefined spacing.
3. 3. The device of claim 1, wherein the downsampling method comprises selecting evenly spaced samples within the bi-predictive block such that a total number of the samples does not exceed a predefined threshold.
4. 4. The apparatus of claim 1, wherein the downsampling method comprises dividing the bi-prediction block into a plurality of regions and selecting samples with different spacing within each region.
5. 5. The device of claim 1, wherein the downsampling method comprises selecting all or part of samples included in a prediction sample derivation.
6. 6. The apparatus of claim 1, wherein the downsampling method comprises selecting samples based on a downsampling matrix.
7. 7. The apparatus of claim 1, wherein the downsampling method comprises selecting samples with different spacing in different directions.
8. 8. The device of claim 3, wherein a value of the predefined threshold depends on a Prediction Unit (PU), a Coding Unit (CU), a Coding Tree Unit (CTU), a slice, a frame, or a sequence attribute.
9. 9. The device of claim 4, wherein a number of the regions is based on a Prediction Unit (PU), a Coding Unit (CU), a Coding Tree Unit (CTU), a slice, a frame, or a sequence attribute.
10. 10. The apparatus of claim 4 or 9, further comprising means for deriving a geometry of a region from a height and a width of the bi-predictive block.
11. 11. The apparatus of claim 6, further comprising means for defining an overshoot parameter to control the number of samples.
12. 12. The device of claim 11, wherein the overshoot parameter is based on a Prediction Unit (PU), a Coding Unit (CU), a Coding Tree Unit (CTU), a slice, a frame, or a sequence attribute.
13. 13. A method, comprising: processing the image to predict the block from the prediction samples of the two prediction blocks; Determining when two of the two prediction blocks of the block are within a boundary of the picture, and applying bi-prediction based on the two prediction blocks of the block to obtain a bi-prediction block; Determining when one of the two prediction blocks is at least partially outside the boundary of the image, and applying unidirectional prediction based on the prediction blocks within the image boundary to obtain unidirectional prediction blocks; Deriving filter coefficients based on a selected set of samples of the bi-predictive block, wherein the selected set of samples comprises samples that have been downsampled in the bi-predictive block according to a downsampling method, and At least a portion of the unidirectional prediction block is filtered according to the filter coefficients to generate a filtered unidirectional prediction block.
14. 14. The method of claim 13, wherein the downsampling method comprises selecting uniformly spaced samples within the bi-predictive block having a predefined spacing.
15. 15. The method of claim 13, wherein the downsampling method comprises selecting evenly spaced samples within the bi-predictive block such that a total number of the samples does not exceed a predefined threshold.
16. 16. The method of claim 13, wherein the downsampling method comprises dividing the bi-prediction block into a plurality of regions and selecting samples with different spacing within each region.
17. 17. The method of claim 13, wherein the downsampling method comprises selecting all or part of samples included in a prediction sample derivation.
18. 18. The method of claim 13, wherein the downsampling method comprises selecting samples based on a downsampling matrix.
19. 19. The method of claim 13, wherein the downsampling method comprises selecting samples with different spacing in different directions.
20. 20. The method of claim 15, wherein a value of the predefined threshold depends on a Prediction Unit (PU), a Coding Unit (CU), a Coding Tree Unit (CTU), a slice, a frame, or a sequence attribute.

Description

Methods, apparatuses and computer program products for video encoding and decoding Technical Field The present technical solution relates generally to video encoding and video decoding. Background This section is intended to provide a background or context to the application that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Accordingly, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section. The video coding system may include an encoder that transforms the input video into a compressed representation suitable for storage/transmission and a decoder that may decompress the compressed video representation back into visual form. The encoder may discard some information in the original video sequence in order to represent the video in a more compact form, e.g., to enable storing/transmitting video information at a lower bit rate than might otherwise be required. Disclosure of Invention The independent claims define the scope of protection sought for the various embodiments of the invention. The embodiments and features (if any) described in this specification that do not fall within the scope of the independent claims are to be construed as examples useful for understanding the various embodiments of the invention. Various aspects include a method, an apparatus and a computer readable medium comprising a computer program stored therein, characterized by what is stated in the independent claims. Various embodiments are disclosed in the dependent claims. According to a first aspect, there is provided an apparatus comprising means for processing an image to predict a block from prediction samples of two prediction blocks, means for determining when two of the two prediction blocks of the block are within a boundary of the image, and means for applying bi-prediction based on the two prediction blocks of the block to obtain bi-prediction blocks, means for determining when one of the two prediction blocks is at least partially outside the boundary of the image, and means for applying uni-prediction based on the prediction blocks within the boundary of the image to obtain uni-prediction blocks, means for deriving filter coefficients based on a selected set of samples of the bi-prediction blocks, wherein the selected set of samples comprises samples that have been downsampled in the bi-prediction blocks according to a downsampling method, and means for filtering at least a portion of the uni-prediction blocks according to the filter coefficients to generate a filtered uni-prediction block. According to a second aspect, there is provided a method comprising processing an image to predict a block from predicted samples of two predicted blocks, determining when two of the two predicted blocks of the block are within a boundary of the image and applying bi-prediction based on the two predicted blocks of the block to obtain bi-predicted blocks, determining when one of the two predicted blocks is at least partially outside the boundary of the image and applying uni-prediction based on the predicted blocks within the boundary of the image to obtain uni-predicted blocks, deriving filter coefficients based on a selected set of samples of the bi-predicted blocks, wherein the selected set of samples comprises samples that have been downsampled in the bi-predicted blocks according to a downsampling method, and filtering at least a portion of the uni-predicted blocks according to the filter coefficients to generate filtered uni-predicted blocks. According to a third aspect there is provided an apparatus comprising at least one processor, a memory comprising computer program code, the memory and the computer program code being configured to, with the at least one processor, cause the apparatus to perform at least the following, processing an image to predict a block from predicted samples of two predicted blocks, determining when two of the two predicted blocks of the block are within a boundary of the image and applying bi-directional prediction based on the two predicted blocks of the block to obtain bi-directional predicted blocks, determining when one of the two predicted blocks is at least partially outside the boundary of the image and applying uni-directional prediction based on the predicted blocks within the boundary of the image to obtain uni-directional predicted blocks, deriving filter coefficients based on a selected set of samples of the bi-directional predicted blocks, wherein the selected set of samples comprises samples that have been downsampled in the bi-directional predicted blocks according to a downsampling method, and filtering at least a portion of the uni-directional predicted blocks according to the filter coefficients to generate filtered u