KR-20260062908-A - METHOD AND APPARATUS FOR ENCODING/DECODING IMAGE AND RECORDING MEDIUM FOR STORING BITSTREAM

KR20260062908AKR 20260062908 AKR20260062908 AKR 20260062908AKR-20260062908-A

Abstract

A method and apparatus for video encoding/decoding are provided. The video decoding method according to the present invention comprises the steps of: comparing block vector information included in a history-based candidate list with a block vector of a neighboring block used as an IBC block vector candidate for predicting the Intra Block Copy (IBC) of the current block; and adding the block vector information included in the history-based candidate list to an IBC block vector candidate list based on the comparison, wherein the comparison step may be performed only on the last candidate included in the history-based candidate list.

Inventors

이하현
강정원
임성창
이진호
김휘용

Assignees

한국전자통신연구원

Dates

Publication Date: 20260507
Application Date: 20260407
Priority Date: 20190308

Claims (15)

Step of determining the prediction mode of the current block; and In response to the prediction mode of the current block being an Intra Block Copy (IBC) mode, the method includes the step of adding a first candidate included in a history-based candidate list to an IBC motion vector candidate list. In response to the fact that the first candidate is a candidate of the first candidate group that was added relatively later to the history-based candidate list in order among the candidates included in the history-based candidate list, the step of adding the first candidate to the IBC motion vector candidate list is: A step of performing a redundancy check by comparing the first candidate with a second candidate included in the IBC motion vector candidate list; and In response to the result of the above redundancy check indicating that the first candidate is different from the second candidate, the method includes the step of adding the first candidate to the IBC candidate list. In response to the fact that the first candidate is a candidate of the second candidate group that was added relatively earlier to the history-based candidate list in order among the candidates included in the history-based candidate list, the step of adding the first candidate to the IBC motion vector candidate list includes the step of adding the first candidate included in the history-based candidate list to the IBC candidate list without performing the redundancy check. The number of candidates in the first candidate group is smaller than the number of candidates in the second candidate group, and A video decoding method characterized by the number of candidates in the second candidate group being multiple.
In paragraph 1, An image decoding method characterized in that the step of adding the first candidate to the IBC motion vector candidate list is performed only when the size of the current block is greater than 16.
In paragraph 1, An image decoding method characterized in that the second candidate included in the above IBC candidate list is configured using the neighbor block of the above current block.
In paragraph 1, An image decoding method characterized in that the above redundancy check is performed only when the number of IBC candidates included in the above IBC candidate list is smaller than the maximum number of candidates that can be included in the above IBC candidate list.
In paragraph 4, A video decoding method characterized by the step of adding the first candidate to the IBC motion vector candidate list being performed until the number of IBC candidates included in the IBC candidate list reaches the maximum number of candidates that can be included in the IBC candidate list.
In paragraph 3, An image decoding method characterized in that the neighbor block is either a block adjacent to the left of the current block or a block adjacent to the top of the current block.
In paragraph 1, An image decoding method characterized in that the candidate of the above history-based candidate list includes vector information for copying a block decoded prior to the decoding of the current block.
Step of determining the prediction mode of the current block; and In response to the prediction mode of the current block being an Intra Block Copy (IBC) mode, the method includes the step of adding a first candidate included in a history-based candidate list to an IBC motion vector candidate list. In response to the fact that the first candidate is a candidate of the first candidate group that was added relatively later to the history-based candidate list in order among the candidates included in the history-based candidate list, the step of adding the first candidate to the IBC motion vector candidate list is: A step of performing a redundancy check by comparing the first candidate with a second candidate included in the IBC motion vector candidate list; and In response to the result of the above redundancy check indicating that the first candidate is different from the second candidate, the method includes the step of adding the first candidate to the IBC candidate list. In response to the fact that the first candidate is a candidate of the second candidate group that was added relatively earlier to the history-based candidate list in order among the candidates included in the history-based candidate list, the step of adding the first candidate to the IBC motion vector candidate list includes the step of adding the first candidate included in the history-based candidate list to the IBC candidate list without performing the redundancy check. The number of candidates in the first candidate group is smaller than the number of candidates in the second candidate group, and A video encoding method characterized by the number of candidates in the second candidate group being multiple.
In paragraph 8, An image encoding method characterized in that the step of adding the first candidate to the IBC motion vector candidate list is performed only when the size of the current block is greater than 16.
In paragraph 8, A video encoding method characterized in that the second candidate included in the above IBC candidate list is configured using the neighbor block of the above current block.
In paragraph 8, A video encoding method characterized in that the above redundancy check is performed only when the number of IBC candidates included in the above IBC candidate list is smaller than the maximum number of candidates that can be included in the above IBC candidate list.
In Paragraph 11, A video encoding method characterized by the step of adding the first candidate to the IBC motion vector candidate list being performed until the number of IBC candidates included in the IBC candidate list reaches the maximum number of candidates that can be included in the IBC candidate list.
In Paragraph 10, An image encoding method characterized in that the neighbor block is either a block adjacent to the left of the current block or a block adjacent to the top of the current block.
In paragraph 8, An image encoding method characterized in that the candidate of the history-based candidate list includes vector information for copying a block encoded prior to the encoding of the current block.
In a non-transient computer-readable recording medium storing a bitstream generated by a video encoding method, The above image encoding method is, Step of determining the prediction mode of the current block; and In response to the prediction mode of the current block being an Intra Block Copy (IBC) mode, the method includes the step of adding a first candidate included in a history-based candidate list to an IBC motion vector candidate list. In response to the fact that the first candidate is a candidate of the first candidate group that was added relatively later to the history-based candidate list in order among the candidates included in the history-based candidate list, the step of adding the first candidate to the IBC motion vector candidate list is: A step of performing a redundancy check by comparing the first candidate with a second candidate included in the IBC motion vector candidate list; and In response to the result of the above redundancy check indicating that the first candidate is different from the second candidate, the method includes the step of adding the first candidate to the IBC candidate list. In response to the fact that the first candidate is a candidate of the second candidate group that was added relatively earlier to the history-based candidate list in order among the candidates included in the history-based candidate list, the step of adding the first candidate to the IBC motion vector candidate list includes the step of adding the first candidate included in the history-based candidate list to the IBC candidate list without performing the redundancy check. The number of candidates in the first candidate group is smaller than the number of candidates in the second candidate group, and A non-transient computer-readable recording medium characterized by the number of candidates in the second candidate group being multiple.

Description

Method and apparatus for encoding/decoding image and recording medium for storing bitstream The present invention relates to an image encoding/decoding method, an apparatus, and a recording medium storing a bitstream. Specifically, the present invention relates to a method for encoding/decoding an image using a candidate list. Recently, the demand for high-resolution, high-quality video, such as HD (High Definition) and UHD (Ultra High Definition) video, has been increasing across various application fields. As video data becomes higher in resolution and quality, the relative volume of data increases compared to conventional video data; consequently, transmission and storage costs increase when video data is transmitted using existing wired or wireless broadband lines or stored using existing storage media. To address these issues arising from the increase in video data resolution and quality, high-efficiency video encoding and decoding technologies for video with higher resolution and quality are required. Various video compression technologies exist, such as inter-frame prediction technology that predicts pixel values in the current picture from previous or subsequent pictures, intra-frame prediction technology that predicts pixel values in the current picture using pixel information within the current picture, transformation and quantization technology for compressing the energy of residual signals, and entropy coding technology that assigns short codes to values with high frequency and long codes to values with low frequency; by utilizing these video compression technologies, video data can be effectively compressed for transmission or storage. FIG. 1 is a block diagram showing the configuration according to one embodiment of an encoding device to which the present invention is applied. FIG. 2 is a block diagram showing the configuration according to one embodiment of a decoding device to which the present invention is applied. Figure 3 is a diagram schematically showing the segmentation structure of an image when encoding and decoding an image. Figure 4 is a diagram illustrating an example of an in-screen prediction process. Figure 5 is a diagram illustrating an example of an inter-frame prediction process. Figure 6 is a diagram illustrating the process of transformation and quantization. Figure 7 is a diagram illustrating reference samples available for in-screen prediction. FIGS. 8 and 9 are drawings illustrating a method for adding neighboring blocks adjacent to the current block to a candidate list according to an embodiment of the present invention. FIGS. 10 and FIGS. 11 are drawings for explaining a method of adding a surrounding block to a candidate list by considering the length of contact between the current block and the surrounding block according to an embodiment of the present invention. FIGS. 12 and FIGS. 13 are drawings illustrating a method for adding surrounding blocks to a candidate list by taking into account the size of surrounding blocks, according to an embodiment of the present invention. FIGS. 14 and 15 are drawings illustrating a method for adding surrounding blocks to a candidate list by taking into account the depth of surrounding blocks, according to an embodiment of the present invention. FIGS. 16 and 17 are drawings for explaining a method of adding surrounding blocks to a candidate list by considering the division shape of surrounding blocks according to an embodiment of the present invention. FIGS. 18 and 19 are drawings for explaining a method of adding a surrounding block to a candidate list by considering the block shape of the surrounding block according to an embodiment of the present invention. FIG. 20 is a diagram illustrating a method for adding surrounding blocks to a candidate list by considering the encoding/decoding order of surrounding blocks according to an embodiment of the present invention. FIG. 21 is a diagram illustrating a method for adding surrounding blocks to a candidate list by considering the location of surrounding blocks at a specific distance from the location of the current block according to an embodiment of the present invention. FIG. 22 is a diagram illustrating a method for adding surrounding blocks to a candidate list by considering the location of surrounding blocks that are at a specific distance from at least one location among a current picture, subpicture, slice, tile, brick, CTU boundary, CTU row, and CTU column, according to an embodiment of the present invention. FIG. 23 is a diagram illustrating a method for adding block information of a current block to a candidate list according to an embodiment of the present invention. FIG. 24 is a diagram illustrating the process of adding candidates in a candidate list as candidates to an in-screen prediction mode candidate list, a motion vector candidate list, or a merge candidate list, according to an embodiment of the present invention. FIG. 25 is a diagram showing an example of surroun