CN-116569553-B - Method for performing intra block copy padding, decoding apparatus and storage medium

CN116569553BCN 116569553 BCN116569553 BCN 116569553BCN-116569553-B

Abstract

The present disclosure relates generally to video coding, and more particularly to Intra Block Copy (IBC) fill mode. A method for performing IBC filling is disclosed. The method includes receiving an encoded video bitstream, extracting a first syntax element from the encoded video bitstream, the first syntax element indicating that the IBC padding is available for a current video block, extracting a second syntax element from the encoded video bitstream, the second syntax element indicating that the current video block is predicted using IBC padding, extracting at least one syntax element from the encoded video bitstream, partitioning the current video block into at least two sub-partitions based on the at least one syntax element, wherein the at least two sub-partitions include a padding sub-partition and an IBC sub-partition, predicting the padding sub-partition based on predefined padding rules, and predicting the IBC sub-partition based on the predefined IBC rules.

Inventors

XU XIAOZHONG
ZHAO XIN
LIU SHAN

Assignees

腾讯美国有限责任公司

Dates

Publication Date: 20260512
Application Date: 20220916
Priority Date: 20220913

Claims (8)

1. A method for performing Intra Block Copy (IBC) filling in a current video block of a video bitstream, the method comprising: Receiving, by a device, a current video block in an encoded video bitstream, the device comprising a memory storing instructions and a processor in communication with the memory, wherein corresponding reference blocks are partially matched to the current video block, the reference blocks being IBC reference blocks, IBC reference block searching and selecting regions being a local CTU/SB searching region and a non-local CTU/SB searching region, identifying the IBC reference blocks by searching currently reconstructed CTU/SB samples; Extracting, by the device, a first syntax element from the encoded video bitstream, the first syntax element indicating that the IBC fill is available for the current video block; Extracting, by the device, a second syntax element from the encoded video bitstream, the second syntax element indicating that the current video block is predicted using the IBC padding; extracting, by the device, at least one syntax element from the encoded video bitstream; dividing, by the device, the current video block into at least two sub-partitions based on the at least one syntax element, wherein the at least two sub-partitions include a filler sub-partition and an IBC sub-partition; predicting, by the device, the filler sub-partition based on predefined filler rules; predicting, by the device, the IBC sub-partition based on predefined IBC rules; The predicting the filler sub-partition based on the predefined filling rule comprises horizontally expanding samples of a rightmost column in the IBC sub-partition to the filler sub-partition when the IBC sub-partition has been reconstructed and the IBC sub-partition and the filler sub-partition are arranged left and right, predicting each row of the filler sub-partition by the same value as corresponding samples of the rightmost column in the IBC sub-partition, or vertically expanding samples of a bottommost row in the IBC sub-partition to the filler sub-partition when the IBC sub-partition has been reconstructed and the IBC sub-partition and the filler sub-partition are arranged upside down, and predicting each column of the filler sub-partition by the same value as corresponding samples of the bottommost row in the IBC sub-partition.
2. The method according to claim 1, wherein: the at least one syntax element including a fourth syntax element and a fifth syntax element, and The partitioning the current video block into at least two sub-partitions based on the at least one syntax element comprises: Based on the fourth syntax element, partitioning the current video block into the at least two sub-partitions using horizontal partitioning or vertical partitioning, and Based on the fifth syntax element, it is determined whether the filler sub-partition is a first sub-partition of the current video block or a second sub-partition of the current video block.
3. The method according to claim 2, wherein: The at least one syntax element including a third syntax element, and The third syntax element indicates a fraction of the filler sub-partition relative to a size of the current video block.
4. A method according to claim 3, wherein: The score includes at least one of 1/4, 1/2, or 3/4.
5. The method of claim 1, wherein the partitioning the current video block into at least two sub-partitions based on the at least one syntax element comprises: Based on the at least one syntax element, the current video block is partitioned into the at least two sub-partitions along other defined directions than a horizontal direction or a vertical direction.
6. A device for decoding a current video block of a video bitstream, the device comprising: Memory storing instructions, and A processor in communication with the memory, wherein the processor, when executing the instructions, is configured to cause the apparatus to perform the method of any one of claims 1 to 5.
7. A non-transitory computer-readable storage medium storing instructions, wherein the instructions, when executed by a processor, are configured to cause the processor to perform the method of any one of claims 1 to 5.
8. A method of processing a video bitstream, characterized in that the video bitstream is decoded based on the method for performing Intra Block Copy (IBC) filling in a current video block of the video bitstream according to any of claims 1 to 5.

Description

Method for performing intra block copy padding, decoding apparatus and storage medium Cross Reference to Related Applications The present application claims priority from U.S. provisional application No. 63/252,079 filed on day 4 of 10 of 2021. The present application also claims the priority of U.S. non-provisional patent application Ser. No. 17/943,449 filed on month 13 of 2022. The entire contents of the prior application are incorporated herein by reference in their entirety. Technical Field This disclosure describes a range of advanced video coding techniques. In particular, the disclosed technology relates to the implementation and enhancement of Intra Block Copy (Intra bc or IBC) with sample stuffing in video encoding and decoding. Background The background description provided herein is for the purpose of generally presenting the disclosure. Within the scope of what is described in this background section, aspects of the present description that are not otherwise qualifying as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. Video encoding and decoding may be performed using inter-picture prediction with motion compensation. The uncompressed digital video may include a series of pictures, each picture having a spatial dimension of, for example, 1920x1080 luma samples and associated chroma samples or sub-sampled chroma samples. The series of pictures may have a fixed or variable picture rate (alternatively referred to as a frame rate), such as 60 pictures per second or 60 frames per second. Uncompressed video has specific bit rate requirements for streaming or data processing. For example, at 8 bits per pixel per color channel, video with a pixel resolution of 1920x1080, a frame rate of 60 frames per second, and chroma subsampling of 4:2:0 requires a bandwidth of approximately 1.5 Gbit/s. One hour of such video requires more than 600 gigabytes of storage space. One purpose of video encoding and decoding may be to reduce redundancy in an uncompressed input video signal by compression. Compression may help reduce the bandwidth and/or storage space requirements described above, and in some cases may be reduced by two orders of magnitude or more. Lossless compression and lossy compression, and combinations thereof, may be employed. Lossless compression refers to a technique by which an exact copy of the original signal can be reconstructed from the compressed original signal by a decoding process. Lossy compression refers to an encoding/decoding process in which original video information is not fully preserved during encoding and is not fully recovered during decoding. When lossy compression is used, the reconstructed signal may be different from the original signal, but the distortion between the original and reconstructed signals is small enough that the reconstructed signal is usable for the intended application despite some loss of information. In the case of video, lossy compression is widely used in many applications. The amount of distortion that can be tolerated depends on the application. For example, some users consuming video streaming applications may tolerate higher distortion than users of movie or television broadcast applications. The compression rate achieved by a particular coding algorithm may be selected or adjusted to reflect various distortion tolerances, with higher allowable distortion generally allowing the coding algorithm to produce higher losses and higher compression ratios. Video encoders and decoders may employ techniques from a number of broad categories and steps, including, for example, motion compensation, fourier transforms, quantization, and entropy coding. Video codec technology may include a variety of techniques known as intra-coding. In intra coding, sample values are represented without reference to samples or other data from a previously reconstructed reference picture. In some video codecs, a picture is spatially subdivided into blocks of samples. When all sample blocks are encoded in intra mode, a picture may be referred to as an intra picture. Intra pictures and their derivatives (e.g., independent decoder refresh pictures) may be used to reset decoder states and thus may be used as the first picture in an encoded video bitstream and video session, or as a still picture. The samples of the intra-predicted block may then be frequency domain transformed and the generated transform coefficients may be quantized prior to entropy encoding. Intra-prediction represents a technique that minimizes sample values in the pre-transform domain. In some cases, the smaller the Direct Current (DC) value and the smaller the Alternating Current (AC) coefficient after transformation, the fewer bits are required to represent the block after entropy encoding at a given quantization step. Conventional intra-coding (e.g., from intra-coding known in techniques such as MPEG-2 generation coding) does not use int