Intra prediction method, apparatus and computer storage medium

Abstract

An intra prediction method, device and computer storage medium, the intra prediction method comprising: obtaining an aspect ratio of a current decoding block and an aspect ratio of a reference decoding block, wherein the reference decoding block is a decoding block related to the current decoding block (S101); when the aspect ratio of the current decoding block and the aspect ratio of the reference decoding block are different, adjusting a replacement angular prediction mode corresponding to the reference decoding block to obtain an adjusted replacement angular prediction mode, the replacement angular prediction mode being an angular prediction mode extended in a wide angular mode (S102); and constructing a prediction mode list of the current decoding block according to the adjusted replacement angular prediction mode to perform intra prediction on the current decoding block (S103).

Description

[0001] This application is a divisional application of Chinese patent application No. 201980086353.9, entitled "Intra-frame prediction method, apparatus and computer storage medium", which entered the Chinese national phase of PCT international patent application PCT / CN2019 / 070155, filed on January 2, 2019. Technical Field

[0002] This application relates to the field of video coding, and more particularly to an intra-frame prediction method, apparatus, and computer storage medium. Background Technology

[0003] In the luma prediction process of next-generation video coding standards such as H.266 or Versatile Video Coding (VVC), a Most Probable Modes (MPM) list is constructed to reduce entropy coding. This list stores the optimal prediction modes of the adjacent upper and left blocks of the current decoding block. Based on the principle of high spatial similarity, the selected prediction mode of the current block is highly likely to be the same as one of the modes in the MPM list, thus allowing encoding of the current block's prediction mode with fewer bits. However, due to the wide-angle mode of non-square blocks, the obtained prediction mode is the opposite direction of the closest mode to the actual prediction direction. Consequently, when performing intra-frame luma prediction using the MPM list, the accuracy of intra-frame prediction is greatly reduced, thereby decreasing encoding and decoding efficiency. Summary of the Invention

[0004] This application provides an intra-frame prediction method, apparatus, and computer storage medium, which can effectively improve the accuracy of intra-frame prediction and improve encoding and decoding efficiency.

[0005] The technical solution of this application embodiment is implemented as follows:

[0006] An intra-frame prediction method, the method comprising:

[0007] Obtain the aspect ratio of the current decoded block and the aspect ratio of the reference decoded block, wherein the reference decoded block is a decoded block related to the current decoded block;

[0008] When the aspect ratio of the current decoded block is different from that of the reference decoded block, the replacement angle prediction mode corresponding to the reference decoded block is adjusted to obtain the adjusted replacement angle prediction mode, which is an extended angle prediction mode under the wide angle mode.

[0009] Based on the adjusted replacement angle prediction mode, a prediction mode list for the current decoding block is constructed to perform intra-frame prediction on the current decoding block.

[0010] In the above method, adjusting the replacement angle prediction mode to obtain the adjusted replacement angle prediction mode includes:

[0011] From the correspondence between the preset aspect ratio and the angle prediction mode, the maximum angle prediction mode and the minimum angle prediction mode corresponding to the aspect ratio of the current decoding block are determined.

[0012] Based on the maximum angle prediction mode, the minimum angle prediction mode, and the replacement angle prediction mode corresponding to the reference decoding block, an intra-frame angle prediction mode adjacent to the replacement angle prediction mode is obtained and determined as the adjusted replacement angle prediction mode.

[0013] In the above method, adjusting the replacement angle prediction mode to obtain the adjusted replacement angle prediction mode includes:

[0014] An intra-frame angle prediction mode that is opposite in direction to the replacement angle prediction mode is determined, and is thus identified as the adjusted replacement angle prediction mode.

[0015] In the above method, the prediction mode list includes a most probable prediction mode (MPM) list, and constructing the prediction mode list for the current decoding block based on the adjusted replacement angle prediction mode includes:

[0016] The adjusted replacement angle prediction mode is defined as at least one of the intra-frame angle prediction modes adjacent to the replacement angle prediction mode and the intra-frame angle prediction modes with opposite directions to the replacement angle prediction mode.

[0017] The adjusted replacement angle prediction mode is inserted into the initial most probable prediction mode (MPM) list to construct the MPM list.

[0018] In the above method, constructing the prediction mode list for the current decoding block based on the adjusted replacement angle prediction mode includes:

[0019] The MPM list is constructed by replacing at least one of the reference decoding block and the adjacent mode of the reference decoding block in the initial MPM list according to the adjusted replacement angle prediction mode, wherein the adjacent mode is the angle prediction mode adjacent to the replacement angle prediction mode.

[0020] In the above method, before constructing the prediction mode list of the current decoding block based on the adjusted replacement angle prediction mode, the method further includes:

[0021] The selection evaluation criteria for the preset reference row index of the current decoding block are calculated sequentially, and the selection evaluation criteria include, but are not limited to, rate-distortion cost;

[0022] From the preset reference row indexes, the reference row index with the smallest selection criterion is determined as the first preset reference row index;

[0023] Obtain the MPM list construction rule corresponding to the first preset reference row index;

[0024] The initial MPM list is constructed using the MPM list construction rules.

[0025] In the above method, after constructing the prediction mode list for the current decoding block based on the adjusted replacement angle prediction mode, the method further includes:

[0026] Match the optimal prediction mode of the current decoded block with the MPM list;

[0027] When a match is successful, the context model is used to encode the index of the optimal prediction mode of the current decoded block in the MPM list;

[0028] When a match fails, truncated binary codes are used to encode the optimal prediction mode of the current decoded block.

[0029] In the above method, the prediction mode list includes a chroma prediction mode list, and constructing the prediction mode list for the current decoding block based on the adjusted replacement angle prediction mode includes:

[0030] The adjusted replacement angle prediction mode is defined as at least one of the intra-frame angle prediction modes adjacent to the replacement angle prediction mode and the intra-frame angle prediction modes with opposite directions to the replacement angle prediction mode.

[0031] The adjusted replacement angle prediction mode is used as the replacement mode in the initial chroma prediction mode list to construct the chroma prediction mode list corresponding to the current decoding block. The initial chroma prediction mode list is constructed according to a preset chroma intra-frame prediction construction method. Alternatively, the adjusted replacement angle prediction mode replaces the direct mode DM in the initial chroma prediction mode list to construct the chroma prediction mode list.

[0032] In the above method, the step of using the adjusted replacement angle prediction mode as the replacement mode in the initial chromaticity prediction mode list includes:

[0033] Determine the optimal prediction mode for the current decoding block;

[0034] Based on the optimal prediction mode, the chroma intra-frame prediction mode is derived;

[0035] When the intra-chroma prediction mode satisfies the preset prediction mode in the initial chroma prediction mode list, the intra-chroma prediction mode is replaced with the adjusted replacement angle prediction mode.

[0036] In the above method, the prediction mode list includes a multi-direct mode signal marker (MDMS) list, and constructing the prediction mode list for the current decoding block based on the adjusted replacement angle prediction mode includes:

[0037] The adjusted replacement angle prediction mode is defined as at least one of the intra-frame angle prediction modes adjacent to the replacement angle prediction mode and the intra-frame angle prediction modes with opposite directions to the replacement angle prediction mode.

[0038] The adjusted replacement angle prediction pattern is inserted before the existing angle fine-tuning row in the initial MDMS list to construct the MDMS list; or, the adjusted replacement angle prediction pattern is used to replace the DM in the initial MDMS list to construct the MDMS list.

[0039] An intra-frame prediction apparatus, the intra-frame prediction apparatus comprising:

[0040] The acquisition section is used to acquire the aspect ratio of the current decoded block and the aspect ratio of the reference decoded block, wherein the reference decoded block is a decoded block related to the current decoded block;

[0041] The adjustment section is used to adjust the replacement angle prediction mode corresponding to the reference decoding block when the aspect ratio of the current decoding block is different from that of the reference decoding block, so as to obtain the adjusted replacement angle prediction mode. The replacement angle prediction mode is an extended angle prediction mode under the wide angle mode.

[0042] The construction section is used to construct a prediction mode list for the current decoding block based on the adjusted replacement angle prediction mode, so as to perform intra-frame prediction on the current decoding block.

[0043] In the above-described apparatus, the intra-frame prediction apparatus further includes: a determining part;

[0044] The determining part is further used to determine the maximum angle prediction mode and the minimum angle prediction mode corresponding to the aspect ratio of the current decoding block from the correspondence between the preset aspect ratio and the angle prediction mode.

[0045] The adjustment section is further configured to obtain an intra-frame angle prediction mode adjacent to the replacement angle prediction mode based on the maximum angle prediction mode, the minimum angle prediction mode, and the replacement angle prediction mode corresponding to the reference decoding block, so as to determine the adjusted replacement angle prediction mode.

[0046] In the above-described apparatus, the adjustment section is further configured to determine an intra-frame angle prediction mode that is opposite in direction to the replacement angle prediction mode, and thus determine it as the adjusted replacement angle prediction mode.

[0047] In the above-described apparatus, the prediction mode list includes an MPM list, and the apparatus further includes an insertion portion;

[0048] The insertion portion is used to select at least one of the intra-frame angle prediction modes adjacent to the replacement angle prediction mode and the intra-frame angle prediction modes with opposite directions to the replacement angle prediction mode as the adjusted replacement angle prediction mode; and to insert the adjusted replacement angle prediction mode into the initial most probable prediction mode (MPM) list to construct the MPM list.

[0049] In the above-described device, the device further includes: a replacement part;

[0050] The replacement portion is used to replace at least one of the reference decoding block and the adjacent mode of the reference decoding block in the initial MPM list according to the adjusted replacement angle prediction mode, thereby constructing the MPM list, wherein the adjacent mode is the angle prediction mode adjacent to the replacement angle prediction mode.

[0051] In the above-described device, the device further includes: a computing section;

[0052] The calculation section is used to sequentially calculate the selection evaluation criteria of the preset reference row index of the current decoding block, and the selection evaluation criteria include, but are not limited to, rate-distortion cost;

[0053] The determining part is further configured to determine, from the preset reference row indexes, the reference row index with the smallest selection evaluation criterion as the first preset reference row index;

[0054] The acquisition part is also used to acquire the MPM list construction rule corresponding to the first preset reference row index;

[0055] The construction part is also used to construct the initial MPM list using the MPM list construction rules.

[0056] In the above-described apparatus, the apparatus further includes: a matching section and an encoding section;

[0057] The matching part is used to match the optimal prediction mode of the current decoded block with the MPM list, wherein the optimal prediction mode is determined by the encoder according to a preset determination strategy.

[0058] The encoding portion is used to encode the index of the optimal prediction mode of the current decoded block in the MPM list using a context model when a match is successful; and to encode the optimal prediction mode of the current decoded block using truncated binary codes when a match fails.

[0059] In the aforementioned apparatus, the prediction mode list includes a chromaticity prediction mode list.

[0060] The construction portion is further configured to: use at least one of the intra-frame angle prediction modes adjacent to the replacement angle prediction mode and the intra-frame angle prediction modes with opposite directions to the replacement angle prediction mode as the adjusted replacement angle prediction mode; use the adjusted replacement angle prediction mode as the replacement mode in the initial chroma prediction mode list to construct the chroma prediction mode list corresponding to the current decoding block, wherein the initial chroma prediction mode list is constructed according to a preset chroma intra-frame prediction construction method; or, replace the direct mode DM in the initial chroma prediction mode list with the adjusted replacement angle prediction mode to construct the chroma prediction mode list.

[0061] In the above apparatus, the determining part is further configured to determine the optimal prediction mode of the current decoding block; and derive the chroma intra-frame prediction mode based on the optimal prediction mode;

[0062] The replacement part is further configured to replace the chroma intra-frame prediction mode with the adjusted replacement angle prediction mode when the chroma intra-frame prediction mode satisfies the preset prediction mode in the initial chroma prediction mode list.

[0063] In the above apparatus, the insertion portion is further configured to use at least one of an intra-frame angle prediction mode adjacent to the replacement angle prediction mode and an intra-frame angle prediction mode with a direction opposite to the replacement angle prediction mode as the adjusted replacement angle prediction mode; to construct an MDMS list before inserting the adjusted replacement angle prediction mode into the existing angle fine-tuning row in the initial MDMS list; or, to construct the MDMS list by replacing the DM in the initial MDMS list according to the adjusted replacement angle prediction mode.

[0064] An intra-frame prediction apparatus includes a processor, a memory storing processor-executable instructions, a communication interface, and a bus for connecting the processor, the memory, and the communication interface. When the instructions are executed, the processor implements the intra-frame prediction method as described above.

[0065] A computer-readable storage medium having a program stored thereon for use in an intra-frame prediction apparatus, wherein the program, when executed by a processor, implements the intra-frame prediction method as described in any of the preceding claims.

[0066] This application provides an intra-frame prediction method, apparatus, and computer storage medium. The method involves obtaining the aspect ratio of the current decoded block and the aspect ratio of a reference decoded block, where the reference decoded block is a decoded block related to the current decoded block. When the aspect ratios of the current decoded block and the reference decoded block are different, the replacement angle prediction mode corresponding to the reference decoded block is adjusted to obtain an adjusted replacement angle prediction mode, which is an extended angle prediction mode under the wide-angle mode. Based on the adjusted replacement angle prediction mode, a prediction mode list for the current decoded block is constructed for intra-frame prediction of the current decoded block. Therefore, in this application's embodiments, when the intra-frame prediction apparatus determines that the aspect ratios of the current decoded block and the reference decoded block are different, the intra-frame prediction apparatus adjusts the replacement angle prediction mode of the reference decoded block to the nearest direction that is in the same direction as the true prediction direction of the adjacent adjustment unit, or the opposite direction with the same angle, and adds it to the MPM list. This improves the accuracy of the prediction angle, and when performing luminance intra-frame prediction through the MPM list, the accuracy of intra-frame prediction is greatly improved, thereby improving coding efficiency. Attached Figure Description

[0067] Figure 1 A schematic diagram of the intra-frame prediction mode provided in an embodiment of this application;

[0068] Figure 2 A schematic diagram illustrating the 67 intra-frame prediction modes supported by VVC as provided in the embodiments of this application;

[0069] Figure 3 A schematic diagram of the wide-angle mode in VTM2.0 provided in the embodiments of this application;

[0070] Figure 4 This is an example of an intra-prediction mode for a coded block whose width is greater than its height.

[0071] Figure 5 A schematic diagram of the wide-angle mode in VTM3.0 provided in the embodiments of this application;

[0072] Figure 6A flowchart illustrating the intra-frame prediction method provided in an embodiment of this application;

[0073] Figure 7 A schematic diagram of vertical prediction provided for an embodiment of this application;

[0074] Figure 8 A schematic diagram of horizontal prediction provided for embodiments of this application;

[0075] Figure 9 A schematic diagram of the chroma intra-frame candidate mode set provided in an embodiment of this application;

[0076] Figure 10 A schematic diagram of chroma blocks and luminance blocks provided in the embodiments of this application;

[0077] Figure 11 A structural block diagram of a video encoder provided in an embodiment of this application;

[0078] Figure 12 A structural block diagram of a video decoder provided in an embodiment of this application;

[0079] Figure 13 This is a schematic diagram illustrating the implementation process of an intra-frame prediction method proposed in an embodiment of this application;

[0080] Figure 14 This application provides an exemplary existing wide-angle mode for determining the optimal prediction mode of adjacent blocks in an embodiment of the present application.

[0081] Figure 15 This is a schematic diagram of the composition structure of the intra-frame prediction device proposed in the embodiments of this application. Figure 1 ;

[0082] Figure 16 This is a schematic diagram of the composition structure of the intra-frame prediction device proposed in the embodiments of this application. Figure 2 . Detailed Implementation

[0083] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are merely for explaining the relevant application and not for limiting the application. Furthermore, it should be noted that, for ease of description, only the parts relevant to the application are shown in the accompanying drawings.

[0084] In video coding, the predicted value for the current processing block is constructed using existing spatially or temporally reconstructed images. Only the difference between the true and predicted values ​​is transmitted to reduce the amount of data transmitted. Intra-frame prediction utilizes spatial correlations within or over image regions. Intra-frame prediction for the current processing block can be performed using pixels from already processed neighboring blocks; for example, the predicted value for the current processing block can be constructed using the row above and column to the left. Figure 1 This is a schematic diagram of intra-frame prediction, such as... Figure 1 As shown, the pixels of the adjacent processing blocks are used to predict each pixel of the current processing block.

[0085] The choice of prediction direction is also important when performing intra-frame prediction. Specifically, when constructing the prediction value of the current processing block using pixels from neighboring coded blocks, various prediction directions can be used. Figure 2 For the 67 intra-frame prediction modes supported by VVC, such as Figure 2 As shown, among the 67 intra-frame prediction modes, there are 65 prediction directions with prediction direction index numbers 2-66, as well as the PLANA mode with index number 0 and the DC mode with index number 1.

[0086] On the one hand, in the embodiments of this application, based on the above... Figure 2 Since the prediction direction of the 65 angle prediction modes is defined clockwise as between -135 degrees (mode 2) and 45 degrees (mode 66), this angle range definition is for compatibility with the direction specified by the High Efficiency Video Coding (HEVC) standard and does not take into account the Quadtree Plus Binary Tree (QTBT) structure added in the next-generation video coding standard (VVC). Due to the introduction of the QTBT structure, some non-square blocks will be generated. To address non-square blocks, a wide-angle mode was proposed in proposal K0500 at the Kth meeting of the Joint Video Experts Team (JVET).

[0087] The wide-angle mode is only applicable to non-square blocks, as shown below:

[0088] If the width of the decoded block is greater than its height, the angle in the upper right direction can exceed 45 degrees;

[0089] If the height of the decoding block is greater than its width, the angle in the lower left direction can exceed 45 degrees.

[0090] Specifically, for non-square blocks, extended wide-angle modes will be used to replace several traditional angle prediction modes (i.e., modes 2 to 66). The number of traditional angle modes that need to be replaced is related to the ratio of the long side to the short side of the decoded block. The larger the ratio, the more traditional angle modes need to be replaced with wide-angle modes, as shown in Table 1.

[0091] Table 1K0500 lists the traditional intra-frame modes that need to be replaced with wide-angle mode.

[0092]

[0093] In Table 1, W represents the width of the decoding block, and H represents the height of the decoding block. When the width is greater than the height, the angle located in the lower left direction needs to be replaced with a wider angle mode in the upper right direction exceeding 45 degrees. When the aspect ratio is 2, modes 2, 3, 4, 5, 6, and 7 will be replaced with the corresponding wide angle modes 67, 68, 69, 70, 71, and 72; when the aspect ratio is greater than 2, modes 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11 will be replaced with the corresponding wide angle modes 67, 68, 69, 70, 71, 72, 73, 74, 75, and 76. When the height is greater than the width, the angle in the upper right direction needs to be replaced with the wider angle mode in the lower left direction, which is more than 45 degrees away. When the aspect ratio is 2, the modes 61, 62, 63, 64, 65, and 66 will be replaced with the wide angle modes -6, -5, -4, -3, -2, and -1 respectively. When the aspect ratio is greater than 2, the modes 57, 58, 59, 60, 61, 62, 63, 64, 65, and 66 will be replaced with the wide angle modes -10, -9, -8, -7, -6, -5, -4, -3, -2, and -1 respectively.

[0094] like Figure 3 As shown, VTM2.0's wide-angle mode includes 85 angular direction modes, as well as PLANA and DC modes. Modes -10 to -1 and modes 67 to 76 extend beyond the range of 45 degrees to -135 degrees, thus constituting the wide-angle mode. Angle directions within the clockwise range of 45 degrees (mode 66) to -135 degrees (mode 2) are designed for square blocks.

[0095] Each wide-angle prediction direction is associated with a conventional prediction direction. The wide-angle pattern uses the opposite prediction direction to its corresponding conventional prediction pattern, so the reference sample used by the wide-angle pattern and its corresponding conventional prediction pattern are not on the same side (left column or top row).

[0096] Figure 4Taking an intra-prediction mode for a coded block with a width greater than its height as an example, during prediction, some angles in the lower left corner are removed and replaced with wider-angle modes in the upper right corner (exceeding 45 degrees): Mode 2 is replaced with Mode 67, Mode 3 with Mode 68, and Mode 4 with Mode 69. The number of modes that need to be replaced with wider-angle modes is related to the aspect ratio of the decoded block. Specifically, the extended Mode 67 is the opposite of the traditional Mode 3; Mode 3 uses the reference sample on the left, while Mode 67 uses the reference sample on the top. Similarly, Mode 68 is the opposite of the traditional Mode 4, and Mode 69 is the opposite of the traditional Mode 5.

[0097] The latest VVC reference software, VTM 3.0, adopts a unified wide-angle mode proposed in proposal L0279. VTM 2.0.1 has 85 angle modes, including PLANA and DC modes, of which 20 modes extend beyond the range of 45 degrees to -135 degrees, i.e., wide-angle modes. A total of 65 angle modes, from Mode 2 to Mode 66, are designed for predicting the angles of square blocks. The diagonal directions of all square blocks (modes 2, 34, and 66) are included in the prediction mode. However, the prediction mode for non-square blocks does not necessarily cover their diagonal directions. Furthermore, the angle direction of square blocks starts from the bottom left diagonal and extends to the top right diagonal, while the angle direction of non-square blocks does not follow this pattern.

[0098] The unified approach proposed in Proposal L0279 modifies the number of traditional modes that need to be replaced with wide-angle modes, ensuring that the angle range after wide-angle expansion lies precisely between the lower left diagonal and the upper right diagonal, as shown in Table 2. Simultaneously, this approach also appropriately modifies the orientation of the expanded wide-angle modes and the traditional angle modes that need to be replaced, ensuring that they encompass the diagonal direction of the decoded block.

[0099] Table 2. Traditional intra-frame modes in L0279 that need to be replaced with wide-angle mode

[0100]

[0101]

[0102] In non-square blocks, when the ratio of the longer side to the shorter side is 2, 6 patterns need to be replaced; when the ratio is 4, 10 patterns need to be replaced; when the ratio is 8, 12 patterns need to be replaced; and when the ratio is 16, 14 patterns need to be replaced. For example... Figure 5 As shown, there are a total of 93 angle modes, as well as PLANA and DC modes. Among them, 28 angle modes have directions that extend beyond the range of -135 degrees and 45 degrees, i.e., wide-angle modes.

[0103] On the other hand, in the embodiments of this application, based on the above... Figure 2 , Figure 6 This is a schematic diagram of the intra-frame prediction method, such as... Figure 3 As shown, when constructing the predicted value for each pixel with a prediction direction index of 66, pixels numbered 0-16 represent the data from the previous row of the current processing block. Each pixel in the current processing block is filled with pixels along the upper right diagonal.

[0104] Furthermore, in the embodiments of this application, the PLANAR mode is mainly used for regions with relatively smooth image textures and relatively gradual transitions. Its prediction method uses the pixel values ​​of adjacent processing blocks in the four directions (up, down, left, and right) corresponding to the current processing block as reference pixel values, and then performs linear interpolation and averaging calculations. Compared to the PLANAR mode, the DC mode is mainly used for regions with flat images, smooth textures, and few gradual transitions. Specifically, its prediction method is to predict based on the last row of reference pixels decoded above the current processing block and the rightmost column of reference pixels decoded to the left of the current processing block. It can be seen that in intra-frame prediction, both the PLANAR and DC modes are relatively flat methods for constructing prediction blocks. The DC mode fills the entire chroma block using the average value of the reference pixels in the leftmost column of the top row, while the PLANAR mode fills the chroma block using a gradual transition.

[0105] In the above Figure 2 In addition, there are two special direction modes: the VER mode with direction index number 50 and the HOR mode with prediction direction index number 18, namely vertical prediction and horizontal prediction. Figure 7 Schematic diagram of vertical prediction. Figure 5 This is a schematic diagram of horizontal prediction, such as... Figure 7 and 8 As shown, if the prediction direction is vertical, then vertical prediction can be performed based on the pixel values ​​above; if the prediction direction is horizontal, then horizontal prediction can be performed based on the pixel values ​​on the left.

[0106] When performing intra-frame prediction of luminance, it can be done as described above. Figure 2 The system sequentially predicts from 0 to 66 modes, then selects the prediction mode with the smallest difference from the current processing block (i.e., the best match) to construct the predicted value. The encoder writes the difference and prediction direction into the bitstream. The decoder parses the bitstream to obtain the prediction mode index number, then calculates the luminance prediction value. This value is added to the difference signal parsed from the bitstream to obtain the reconstructed luminance value.

[0107] However, chroma intra-frame prediction differs from luma intra-frame prediction. This is because, to reduce encoding and decoding complexity, only a subset of prediction modes are extracted during chroma intra-frame prediction. These modes are combined with cross-component linear model prediction modes to form a candidate mode set, from which one mode is selected for intra-frame prediction. In VVC, the chroma intra-frame candidate mode set includes multiple chroma intra-frame prediction modes, such as Linear Model Prediction (LM), the upper LM_T mode, the left LM_L mode, DC mode, PLANAR mode, vertical VER mode, and horizontal HOR mode, etc.

[0108] Figure 9 This is a schematic diagram of the chroma intra-frame candidate mode set, such as... Figure 9 As shown, the chroma intra-frame candidate mode set can include different modes. Existing technologies can perform chroma intra-frame prediction using different modes. For example, Direct Mode (DM) can characterize the prediction mode of the corresponding luma center block, while Cross-component Linear Model Prediction (CCLM) characterizes the construction of the prediction signal using the scheme of (a*luminance value + b), where a and b are both natural numbers. When DM is any of the DC mode, PLANA mode, VER mode, or HOR mode, this mode can be replaced with the angle mode with the prediction direction index number 66.

[0109] Furthermore, VVC supports separate partitioning of luminance and chrominance, meaning that the partitioning of the two can be inconsistent. Therefore, a single chrominance block may correspond to multiple luminance blocks. Figure 10 This is a schematic diagram showing the arrangement of the luminance blocks and chrominance corresponding to the current block in an embodiment of this application, as shown below. Figure 10 As shown, square 70 on the left represents the chroma block corresponding to the current chroma block, and square 71 on the right represents the current chroma block. When performing intra-frame prediction of the current chroma block, the prediction direction of the center block of chroma block 71 is used, which is... Figure 10 CR brightness block 701 in the right square 70.

[0110] In the embodiments of this application, the above-described intra-frame prediction method can be applied to the intra-frame prediction part of a video coding hybrid framework. Specifically, the above-described intra-frame prediction method can be applied simultaneously to both the encoding and decoding ends. For example, Figure 8 This is a diagram illustrating the video encoding process, such as... Figure 11The diagram illustrates an example of a video coding system provided in this application. The video coding system 200 includes a transform and quantization unit 201, an intra-frame estimation unit 202, an intra-frame prediction unit 203, a motion compensation unit 204, a motion estimation unit 205, an inverse transform and inverse quantization unit 206, a filter control and analysis unit 207, a filtering unit 208, an encoding unit 209, and a decoding image buffer unit 210. The filtering unit 208 can implement deblocking filtering and sample adaptive offset (SAO) filtering, and the encoding unit 209 can implement header information encoding and context-based adaptive binary arithmetic coding (CABAC).For the input raw video signal, a video coding block can be obtained by partitioning it into Coding Tree Units (CTUs). Then, the residual pixel information obtained after intra-frame or inter-frame prediction is transformed by the transform and quantization unit 201, including transforming the residual information from the pixel domain to the transform domain and quantizing the resulting transform coefficients to further reduce the bit rate. Intra-frame estimation unit 202 and intra-frame prediction unit 203 are used to perform intra-frame prediction on the video coding block. Specifically, intra-frame estimation unit 202 and intra-frame prediction unit 203 are used to determine the intra-frame prediction mode to be used to encode the video coding block. Motion compensation unit 204 and motion estimation unit 205 are used to perform inter-frame prediction coding of the received video coding block relative to one or more blocks in one or more reference frames to provide temporal prediction information. The motion estimation performed by motion estimation unit 205 is a process of generating motion vectors, which can estimate the motion of the video coding block. Then, motion compensation unit 204 uses the motion vectors determined by motion estimation unit 205 to generate motion vectors. Motion vectors perform motion compensation; after determining the intra-prediction mode, the intra-prediction unit 203 is also used to provide the selected intra-prediction data to the coding unit 209, and the motion estimation unit 205 also sends the calculated motion vector data to the coding unit 209; in addition, the inverse transform and inverse quantization unit 206 is used to reconstruct the video coding block, reconstructing the residual block in the pixel domain. The reconstructed residual block is processed by the filter control analysis unit 207 and the filtering unit 208 to remove block artifacts, and then the reconstructed residual block is added to a predictive block in the frame of the decoding image buffer unit 210 to generate the reconstructed video coding block; the coding unit 209 is used to encode various coding parameters and quantized transform coefficients. In the CABAC-based coding algorithm, the context content can be based on adjacent coding blocks and can be used to encode information indicating the determined intra-prediction mode, outputting the bitstream of the video signal; and the decoding image buffer unit 210 is used to store the reconstructed video coding block for prediction reference. As video image encoding proceeds, new reconstructed video encoding blocks are continuously generated, and these reconstructed video encoding blocks are stored in the decoding image buffer unit 210.

[0111] See Figure 12 This illustration shows a block diagram example of a video decoding system provided in this application embodiment. The video decoding system 300 includes a decoding unit 301, an inverse transform and inverse quantization unit 302, an intra-frame prediction unit 303, a motion compensation unit 304, a filtering unit 305, and a decoding image buffer unit 306, etc. The decoding unit 301 can perform header information decoding and CABAC decoding, and the filtering unit 305 can perform deblocking filtering and SAO filtering. The input video signal is processed... Figure 2After encoding, the video signal bitstream is output. This bitstream is input into the video decoding system 300, first passing through the decoding unit 301 to obtain the decoded transform coefficients. These transform coefficients are then processed by the inverse transform and inverse quantization unit 302 to generate residual blocks in the pixel domain. The intra-frame prediction unit 303 can generate prediction data for the current video decoding block based on the determined intra-frame prediction mode and data from previously decoded blocks in the current frame or image. The motion compensation unit 304 determines the prediction information for the video decoding block by analyzing motion vectors and other associated syntax elements, and uses this prediction information... The information is used to generate a predictive block of the video block being decoded; the decoded video block is formed by summing the residual block from the inverse transform and inverse quantization unit 302 with the corresponding predictive block generated by the intra-frame prediction unit 303 or the motion compensation unit 304; the decoded video signal is passed through the filtering unit 305 to remove block artifacts, which can improve video quality; then the decoded video block is stored in the decoding image buffer unit 306, which stores reference images for subsequent intra-frame prediction or motion compensation, and is also used for the output of the video signal, thus obtaining the recovered original video signal.

[0112] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0113] In one embodiment, this application provides an intra-frame prediction method. Figure 13 This application provides a schematic diagram of the implementation process of an intra-frame prediction method, which may include:

[0114] S101. Obtain the aspect ratio of the current decoding block and the aspect ratio of the reference decoding block, wherein the reference decoding block is the decoding block related to the current decoding block.

[0115] The intra-frame prediction method provided in this application embodiment is applicable to scenarios where the intra-frame prediction device performs luminance intra-frame prediction or chrominance intra-frame prediction on a video bitstream.

[0116] In this embodiment, the intra-frame prediction device exists in the encoder and decoder, and the specific selection is made according to the actual situation. This embodiment does not impose any specific limitations.

[0117] In this embodiment, the encoder divides the input video frame into various decoding blocks according to a preset partitioning rule, adds each partitioned decoding block to the bitstream, and transmits it to the decoder. Then, the intra-frame prediction device obtains the aspect ratio of the current decoding block and the aspect ratio of the reference decoding block. The reference decoding block is a decoding block related to the current decoding block. The reference decoding block includes, but is not limited to, the reference decoding blocks that are adjacent to the current decoding block on the top and left, or the reference decoding block of the luminance region segmentation block corresponding to the chroma block. The specific selection is made according to the actual situation, and this embodiment does not make specific limitations.

[0118] It should be noted that the intra-frame prediction device divides the width and height of the decoded block to obtain the aspect ratio of the decoded block.

[0119] In this embodiment, the term is not limited to the decoding block. Any unit that subdivides the largest coding block according to different partitioning rules is applicable here, including prediction units, etc. No specific limitation is made here.

[0120] S102. When the aspect ratio of the current decoded block is different from that of the reference decoded block, the replacement angle prediction mode corresponding to the reference decoded block is adjusted to obtain the adjusted replacement angle prediction mode. The replacement angle prediction mode is an extended angle prediction mode under the wide angle mode.

[0121] Once the intra-frame prediction device obtains the aspect ratio of the current decoded block and the reference decoded block, it needs to adjust the replacement angle prediction mode corresponding to the reference decoded block when it determines that the aspect ratio of the current decoded block and the reference decoded block are different, thus obtaining the adjusted replacement angle prediction mode.

[0122] In this embodiment, the intra-frame prediction device compares the aspect ratio of the current decoded block with that of the reference decoded block. When the aspect ratio of the current decoded block is different from that of the reference decoded block, it indicates that the corresponding replacement angle prediction mode of the obtained reference decoded block may be invalid for the current decoded block. In this case, the intra-frame prediction device needs to adjust the replacement angle prediction mode, wherein the replacement angle prediction mode is an extended angle prediction mode under the wide angle mode.

[0123] For example, such as Figure 14As shown, taking the intra-prediction mode of the upper adjacent block as a reference, the upper side is the adjacent block, and the lower side is the current block. If the optimal prediction mode selected by the adjacent block is mode 67, but it is obtained by replacing the traditional mode 2 and transmitted in the bitstream as mode 2, according to the existing MPM list construction scheme, mode 2 is directly put into the MPM list. Since the current block has the same width and height, the wide-angle mode 67 replaced by the traditional mode 2 of the adjacent block is invalid for the current block. The opposite direction of mode 67 is mode 3, and the current block actually selects the prediction mode 2 that is closest to the opposite direction of the prediction mode and adds it to the MPM list. Mode 67 uses the upper reference row, and mode 2 uses the left reference row, which shows that the current block does not inherit the prediction direction of the adjacent block very well.

[0124] In this embodiment of the application, the intra-frame prediction device obtains the intra-frame angle prediction mode corresponding to the reference decoding block; then, the intra-frame prediction device determines the replacement angle prediction mode corresponding to the intra-frame angle prediction mode from the correspondence between the traditional intra-frame mode and the wide-angle mode.

[0125] Specifically, the replacement angle prediction mode corresponding to the reference decoded block is adjusted to obtain the adjusted replacement angle prediction mode. This includes: the intra-frame prediction device determining the maximum and minimum angle prediction modes corresponding to the aspect ratio of the current decoded block from the preset correspondence between aspect ratio and angle prediction modes; then, the intra-frame prediction device obtaining the intra-frame angle prediction mode adjacent to the replacement angle prediction mode based on the maximum angle prediction mode, the minimum angle prediction mode, and the replacement angle prediction mode corresponding to the reference decoded block; finally, the intra-frame prediction device determining the intra-frame angle prediction mode adjacent to the replacement angle prediction mode as the adjusted replacement angle prediction mode.

[0126] For example, the correspondence between the preset aspect ratio and the angle prediction mode is shown in Table 3. Table 3 can be used to determine the range of the preset angle mode corresponding to the aspect ratio of the current decoding block, and then determine the maximum angle prediction mode and the minimum angle prediction mode.

[0127] Table 3. Range of angular prediction modes usable by different shaped decoder blocks (after wide-angle mode replacement)

[0128] 1 Mode 2-66 2 Pattern 8-72 4 Pattern 12-76 8 Pattern 14-78 16 Mode 16-80

[0129] In this embodiment of the application, the maximum angle prediction mode, the minimum angle prediction mode, and the replacement angle prediction mode corresponding to the reference decoding block are input into formula (1) to obtain the adjusted replacement angle prediction mode, wherein formula (1) is:

[0130] dir_W = Clip(minM) C maxM C ,dir) (1)

[0132] Where dir_W represents the intra-frame angle prediction mode adjacent to the replacement angle prediction mode, minM C This represents the minimum angle prediction mode, maxM C dir indicates the maximum angle prediction mode, and dir indicates the replacement angle prediction mode corresponding to the reference decoded block.

[0133] Specifically, adjusting the replacement angle prediction mode corresponding to the reference decoding block to obtain the adjusted replacement angle prediction mode also includes: the intra-frame prediction device determining an intra-frame angle prediction mode with the opposite direction to the replacement angle prediction mode; then the intra-frame prediction device determining the intra-frame angle prediction mode with the opposite direction to the replacement angle prediction mode as the adjusted replacement angle prediction mode.

[0134] For example, if the reference decoded block is mode 2, but the actual predicted mode is 67, mode 67 is invalid for the current decoded block because the width and height are equal. In this case, it is adjusted to the predicted mode 66 that is closest to the predicted mode in the same direction and can be included by the current decoded block. Both modes 67 and 66 use the upper reference row, which allows the current decoded block to better inherit the prediction direction of adjacent blocks.

[0135] In this embodiment, the intra-frame prediction device adjusts the wide-angle mode to the opposite direction of its prediction direction based on the aspect ratio of the reference decoded block and the aspect ratio of the current decoded block.

[0136] For example, if the width of the reference decoded block is greater than its height, and the obtained prediction mode is 2, then the actual prediction mode of the reference decoded block is mode 67. If the current decoded block does not support this mode, and since the opposite of mode 67 is mode 3, we adjust the obtained mode 2 to mode 3 and add it to the MPM list according to the MPM list construction method proposed above. And so on, the opposite of 68 is 4, ...

[0137] S103. Based on the adjusted replacement angle prediction mode, construct a prediction mode list for the current decoding block to perform intra-frame prediction on the current decoding block.

[0138] When the intra-frame prediction device adjusts the replacement angle prediction mode corresponding to the reference decoded block and obtains the adjusted replacement angle prediction mode, the intra-frame prediction device constructs the MPM list of the current decoded block according to the adjusted replacement angle prediction mode, and the intra-frame prediction process of the current decoded block is completed.

[0139] In this embodiment of the application, the preset mode list includes an MPM list. Constructing a prediction mode list for the current decoded block based on the adjusted replacement angle prediction mode includes: the intra-frame prediction device selecting at least one of an intra-frame angle prediction mode adjacent to the replacement angle prediction mode and an intra-frame angle prediction mode with the opposite direction to the replacement angle prediction mode as the adjusted replacement angle prediction mode; then, the intra-frame prediction device inserts the adjusted replacement angle prediction mode into the initial MPM list to construct the MPM list; or, the intra-frame prediction device replaces at least one of the reference decoded block and its adjacent modes in the initial MPM list based on the adjusted replacement angle prediction mode to construct the MPM list, wherein the adjacent mode is the angle prediction mode adjacent to the replacement angle prediction mode.

[0140] It should be noted that there are multiple different modes in the MPM list. For example, just like in VTM3.0, six different modes can be selected.

[0141] Furthermore, the process of the intra-frame prediction device constructing the initial MPM list is as follows: the intra-frame prediction device sequentially calculates the selection evaluation criteria for the preset reference row index of the current decoded block, wherein the selection evaluation criteria include, but are not limited to, rate-distortion cost; the intra-frame prediction device determines the reference row index with the smallest selection evaluation criteria from the preset reference row indices as the first preset reference row index; the intra-frame prediction device obtains the MPM list construction rule corresponding to the first preset reference row index; and then the intra-frame prediction device constructs the initial MPM list using the MPM list construction rule.

[0142] In this embodiment of the application, when the first preset reference row index is 0, the construction rules for the initial MPM list are as follows:

[0143] 1. Replacement angle prediction mode dirA for the left adjacent reference decoded block and replacement angle prediction mode dirB for the upper adjacent reference decoded block;

[0144] 2. PLANA / DC;

[0145] 3. Adjacency patterns of dirA and dirB;

[0146] 4. Patterns: 50, 18, 50-4, 50+4.

[0147] When the first preset reference row index is 1 or 3, the initial MPM list is constructed according to the following rules:

[0148] 1. Replacement angle prediction mode dirA for the left adjacent reference decoded block and replacement angle prediction mode dirB for the upper adjacent reference decoded block;

[0149] 2. Adjacency patterns of dirA and dirB;

[0150] 3. Patterns 2, 34, 66, 26.

[0151] For example, the specific rules by which the intra-frame prediction device adds the adjusted replacement angle prediction mode to the MPM list are as follows: the MPM list is constructed in the following order until it contains 6 different MPM modes.

[0152] a. The reference row index used by the current decoding block is 0:

[0153] 1. Replacement angle prediction mode dirA for the left adjacent reference decoded block and replacement angle prediction mode dirB for the upper adjacent reference decoded block;

[0154] 2. PLANA / DC;

[0155] 3. The replacement angle prediction modes dirA_W and dirB_W after dirA and dirB are adjusted;

[0156] 4. Adjacency patterns of dirA and dirB;

[0157] 5. Patterns: 50, 18, 50-4, 50+4.

[0158] b. The reference row index used by the current block is 1 or 3.

[0159] 1. Replacement angle prediction mode dirA for the left adjacent reference decoded block and replacement angle prediction mode dirB for the upper adjacent reference decoded block;

[0160] 2. The replacement angle prediction modes dirA_W and dirB_W after dirA and dirB are adjusted;

[0161] 3. Adjacency patterns of dirA and dirB;

[0162] 4. Patterns 2, 34, 66, 26.

[0163] It should be noted that during the construction of the MPM list, dir_W can be placed after the pattern PLANARR / DC and before the adjacent pattern; or, dir_W can be placed before the pattern PLANARR / DC; or, dir_W can be placed after the adjacent pattern; or dir_W can be used to replace at least one of dir and dir's adjacent patterns. The specific choice depends on the actual situation, and this application embodiment does not make specific limitations.

[0164] In this embodiment of the application, after the intra-frame prediction device constructs the MPM list of the current decoded block according to the adjusted replacement angle prediction mode, the intra-frame prediction device matches the optimal prediction mode of the current decoded block with the MPM list; when the match is successful, the context model is used to encode the index of the optimal prediction mode of the current decoded block in the MPM list; when the match fails, truncated binary code is used to encode the optimal prediction mode of the current decoded block.

[0165] In this embodiment, the encoder determines the optimal prediction mode of the current decoding block according to a preset selection strategy, and transmits the optimal prediction mode of the current decoding block to the decoder through the bitstream.

[0166] In this embodiment, the prediction mode list includes a chroma prediction mode list. The intra-frame prediction device constructs the prediction mode list for the current decoding block based on the adjusted replacement angle prediction mode. This includes: the intra-frame prediction device selecting at least one of the intra-frame angle prediction modes adjacent to the replacement angle prediction mode and the intra-frame angle prediction modes with opposite directions to the replacement angle prediction mode as the adjusted replacement angle prediction mode; then, the intra-frame prediction device uses the adjusted replacement angle prediction mode as the replacement mode in the initial chroma prediction mode list to construct the chroma prediction mode list corresponding to the current decoding block; or, the intra-frame prediction device replaces the DM in the initial chroma prediction mode list with the adjusted replacement angle prediction mode to construct the chroma prediction mode list. The specific selection is made according to the actual situation, and this embodiment does not impose specific limitations.

[0167] In this embodiment of the application, the initial chroma prediction mode list is constructed according to a preset chroma intra-frame prediction construction method. The initial chroma prediction mode list is as follows: Figure 9 As shown, the replacement mode in the initial chromaticity prediction mode list is 66.

[0168] In this embodiment of the application, the intra-frame prediction device uses the adjusted replacement angle prediction mode as the replacement mode in the initial chroma prediction mode list, including: the intra-frame prediction device determines the optimal prediction mode for the current decoding block; then the intra-frame prediction device derives the chroma intra-frame prediction mode based on the optimal prediction mode; when the chroma intra-frame prediction mode satisfies the preset prediction mode in the initial chroma prediction mode list, the intra-frame prediction device replaces the chroma intra-frame prediction mode with the adjusted replacement angle prediction mode; wherein, the preset prediction mode includes any one of DC mode, planar mode, vertical VER mode, and horizontal HOR mode.

[0169] In this embodiment of the application, when the intra-frame prediction device determines that the chroma intra-frame prediction mode satisfies any one of DC mode, planar mode, vertical VER mode and horizontal HOR mode, the intra-frame prediction device is replaced with the chroma intra-frame prediction mode.

[0170] In this embodiment, the intra-frame prediction device constructs a prediction mode list for the current decoded block based on the adjusted replacement angle prediction mode. This includes: the intra-frame prediction device inserts the adjusted replacement angle prediction mode before the existing angle fine-tuning mode in the initial Multiple Direct Mode Signalling (MDMS) list and constructs an MDMS list; or, the intra-frame prediction device replaces the DM in the initial MDMS list with the adjusted replacement angle prediction mode and constructs an MDMS list. The specific selection depends on the actual situation, and this embodiment does not impose specific limitations.

[0171] In this embodiment of the application, the method for constructing the initial MDMS list is shown in Table 4:

[0172] Table 4. Method for constructing the initial MDMS list

[0173]

[0174]

[0175] In this embodiment, the intra-frame prediction device inserts a line before the existing angle mode fine-tuning line in the initial MDMS list. This line is the adjusted replacement angle prediction mode; or the DM line is replaced according to the adjusted replacement angle prediction mode. The specific choice depends on the actual situation, and this embodiment does not impose any specific limitations.

[0176] Understandably, when the intra-frame prediction device determines that the aspect ratio of the current decoded block is different from that of the reference decoded block, it adjusts the replacement angle prediction mode of the reference decoded block to the nearest direction that is in the same direction as the true prediction direction of the adjacent adjustment unit, or the opposite direction with the same angle, and adds it to the MPM list. This improves the accuracy of the prediction angle. When performing luma intra-frame prediction through the MPM list and chroma intra-frame prediction through the chroma prediction mode list, the accuracy of intra-frame prediction is greatly improved, thereby improving coding efficiency.

[0177] Based on the above embodiments, in another embodiment of this application, Figure 15 This is a schematic diagram of the composition structure of the intra-frame prediction device proposed in the embodiments of this application. Figure 1 ,like Figure 15 As shown, the intra-frame prediction apparatus 1 proposed in this application embodiment may include an acquisition part 11, an adjustment part 12, a construction part 13, a determination part 14, an insertion part 15, a replacement part 16, a calculation part 17, a matching part 18, and an encoding part 19.

[0178] The acquisition section 11 is used to acquire the aspect ratio of the current decoding block and the aspect ratio of the reference decoding block, wherein the reference decoding block is a decoding block related to the current decoding block;

[0179] The adjustment part 12 is used to adjust the replacement angle prediction mode corresponding to the reference decoding block when the aspect ratio of the current decoding block is different from that of the reference decoding block, so as to obtain the adjusted replacement angle prediction mode. The replacement angle prediction mode is an extended angle prediction mode under the wide angle mode.

[0180] The construction part 13 is used to construct a prediction mode list for the current decoding block according to the adjusted replacement angle prediction mode, so as to perform intra-frame prediction on the current decoding block.

[0181] Furthermore, in an implementation of this application, the intra-frame prediction device further includes: a determination part 14;

[0182] The determining unit 14 is further configured to determine the maximum angle prediction mode and the minimum angle prediction mode corresponding to the aspect ratio of the current decoding block from the correspondence between the preset aspect ratio and the angle prediction mode.

[0183] The adjustment portion 12 is further configured to obtain an intra-frame angle prediction mode adjacent to the replacement angle prediction mode based on the maximum angle prediction mode, the minimum angle prediction mode, and the replacement angle prediction mode corresponding to the reference decoding block, so as to determine the adjusted replacement angle prediction mode.

[0184] Furthermore, in an implementation of this application, the adjustment portion 12 is also used to determine an intra-frame angle prediction mode that is opposite in direction to the replacement angle prediction mode, so as to determine the adjusted replacement angle prediction mode.

[0185] Furthermore, in an implementation of this application, the prediction mode list includes an MPM list, and the device further includes: an insertion portion 15;

[0186] The insertion portion 15 is used to select at least one of the intra-frame angle prediction modes adjacent to the replacement angle prediction mode and the intra-frame angle prediction modes with opposite directions to the replacement angle prediction mode as the adjusted replacement angle prediction mode; and to insert the adjusted replacement angle prediction mode into the initial most probable prediction mode (MPM) list to construct the MPM list.

[0187] Furthermore, in an embodiment of this application, the device further includes: a replacement portion 16;

[0188] The replacement portion 16 is used to replace at least one of the reference decoding block and the adjacent mode of the reference decoding block in the initial MPM list according to the adjusted replacement angle prediction mode, thereby constructing the MPM list, wherein the adjacent mode is the angle prediction mode adjacent to the replacement angle prediction mode.

[0189] Furthermore, in an implementation of this application, the apparatus further includes: a calculation section 17; the calculation section 17 is configured to sequentially calculate the selection evaluation criteria of the preset reference row index of the current decoded block, the selection evaluation criteria including but not limited to rate-distortion cost; the determination section 14 is further configured to determine, from the preset reference row indexes, the reference row index with the smallest selection evaluation criteria as the first preset reference row index; the acquisition section 11 is further configured to acquire the MPM list construction rule corresponding to the first preset reference row index; the construction section 13 is further configured to construct the initial MPM list using the MPM list construction rule. Furthermore, in an implementation of this application, the apparatus further includes: a matching section 18 and an encoding section 19;

[0190] The matching portion 18 is used to match the optimal prediction mode of the current decoding block with the MPM list;

[0191] The encoding portion 19 is used to encode the index of the optimal prediction mode of the current decoded block in the MPM list using a context model when a match is successful; and to encode the optimal prediction mode of the current decoded block using truncated binary codes when a match fails.

[0192] Furthermore, in implementation of this application, the prediction mode list includes a chromaticity prediction mode list.

[0193] The construction portion 13 is further configured to: use at least one of the intra-frame angle prediction modes adjacent to the replacement angle prediction mode and the intra-frame angle prediction modes with opposite directions to the replacement angle prediction mode as the adjusted replacement angle prediction mode; use the adjusted replacement angle prediction mode as the replacement mode in the initial chroma prediction mode list to construct the chroma prediction mode list corresponding to the current decoding block, wherein the initial chroma prediction mode list is constructed according to a preset chroma intra-frame prediction construction method; or, replace the direct mode DM in the initial chroma prediction mode list with the adjusted replacement angle prediction mode to construct the chroma prediction mode list.

[0194] Furthermore, in the implementation of this application, the determining part 14 is also used to determine the optimal prediction mode of the current decoding block; and derive the chroma intra-frame prediction mode based on the optimal prediction mode.

[0195] The replacement portion 16 is further configured to replace the chroma intra-frame prediction mode with the adjusted replacement angle prediction mode when the chroma intra-frame prediction mode satisfies the preset prediction mode in the initial chroma prediction mode list.

[0196] Furthermore, in an implementation of this application, the insertion portion 15 is also used to select at least one of the intra-frame angle prediction modes adjacent to the replacement angle prediction mode and the intra-frame angle prediction modes with opposite directions to the replacement angle prediction mode as the adjusted replacement angle prediction mode; to construct an MDMS list by inserting the adjusted replacement angle prediction mode before the existing angle fine-tuning row in the initial MDMS list; or, to construct the MDMS list by replacing the DM in the initial MDMS list according to the adjusted replacement angle prediction mode.

[0197] Figure 16 This is a schematic diagram of the composition structure of the intra-frame prediction device proposed in the embodiments of this application. Figure 2 ,like Figure 16 As shown, the intra-frame prediction device 1 proposed in this application embodiment may further include a processor 110, a memory 111 storing instructions executable by the processor 110, a communication interface 112, and a bus 113 for connecting the processor 110, the memory 111, and the communication interface 112.

[0198] In the embodiments of this application, the processor 110 can be at least one of the following: Application-Specific Integrated Circuit (ASIC), Digital Signal Processor (DSP), Digital Signal Processing Device (DSPD), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), Central Processing Unit (CPU), Controller, Microcontroller, and Microprocessor. It is understood that for different devices, the electronic device used to implement the above-mentioned processor function can also be other types, and this application embodiment does not specifically limit this. The device 1 may also include a memory 111, which can be connected to the processor 110. The memory 111 is used to store executable program code, which includes computer operation instructions. The memory 111 may include high-speed RAM memory and may also include non-volatile memory, such as at least two disk drives.

[0199] In embodiments of this application, bus 113 is used to connect communication interface 112, processor 110, and memory 111, as well as the mutual communication between these devices.

[0200] In embodiments of this application, memory 111 is used to store instructions and data.

[0201] Further, in the embodiments of this application, the processor 110 is configured to obtain the aspect ratio of the current decoded block and the aspect ratio of the reference decoded block, wherein the reference decoded block is a decoded block related to the current decoded block; when the aspect ratio of the current decoded block and the aspect ratio of the reference decoded block are different, the replacement angle prediction mode corresponding to the reference decoded block is adjusted to obtain the adjusted replacement angle prediction mode, wherein the replacement angle prediction mode is an extended angle prediction mode under the wide angle mode; based on the adjusted replacement angle prediction mode, a prediction mode list for the current decoded block is constructed to perform intra-frame prediction on the current decoded block.

[0202] In practical applications, the aforementioned memory 111 can be a volatile first memory, such as random-access memory (RAM); or a non-volatile first memory, such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid-state drive (SSD); or a combination of the above types of first memory, and provide instructions and data to the processor 110.

[0203] Furthermore, in this embodiment, the functional modules can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional module.

[0204] If the integrated unit is implemented as a software functional module and is not sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this embodiment, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the method of this embodiment. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0205] This application proposes an apparatus in which an intra-frame prediction device acquires the aspect ratio of a current decoded block and the aspect ratio of a reference decoded block, wherein the reference decoded block is a decoded block related to the current decoded block. When the aspect ratios of the current decoded block and the reference decoded block are different, the intra-frame prediction device adjusts the replacement angle prediction mode corresponding to the reference decoded block to obtain an adjusted replacement angle prediction mode, which is an extended angle prediction mode under the wide-angle mode. Based on the adjusted replacement angle prediction mode, the intra-frame prediction device constructs a prediction mode list for the current decoded block to perform intra-frame prediction on the current decoded block. Therefore, in the embodiments of this application, when the intra-frame prediction device determines that the aspect ratios of the current decoded block and the reference decoded block are different, it adjusts the replacement angle prediction mode of the reference decoded block to the nearest direction that is in the same direction as the true prediction direction of the adjacent adjustment unit, or the opposite direction with the same angle, and adds it to the MPM list, thereby improving the accuracy of the prediction angle. When performing luminance intra-frame prediction through the MPM list, the accuracy of intra-frame prediction is greatly improved, thus improving coding efficiency.

[0206] This application provides a computer-readable storage medium having a program stored thereon, which, when executed by a processor, implements the intra-frame prediction method as described above.

[0207] Specifically, the program instructions corresponding to an intra-frame prediction method in this embodiment can be stored on storage media such as optical discs, hard disks, and USB flash drives. When the program instructions corresponding to an intra-frame prediction method in the storage media are read or executed by an electronic device, the intra-frame prediction method as described above is implemented.

[0208] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of hardware embodiments, software embodiments, or embodiments combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0209] This application is described with reference to schematic and / or block diagrams of implementations of methods, apparatus (systems), and computer program products according to embodiments of this application. It should be understood that each block of the schematic and / or block diagrams can be implemented by computer program instructions, and combinations of blocks in the schematic and / or block diagrams can be implemented. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the schematic and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0210] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in the implementation flow diagram. Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0211] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0212] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application.

[0213] Industrial applicability

[0214] This application provides an intra-frame prediction method, apparatus, and computer storage medium. The intra-frame prediction apparatus obtains the aspect ratio of the current decoded block and the aspect ratio of a reference decoded block, wherein the reference decoded block is a decoded block related to the current decoded block. When the aspect ratio of the current decoded block and the aspect ratio of the reference decoded block are different, the intra-frame prediction apparatus adjusts the replacement angle prediction mode corresponding to the reference decoded block to obtain an adjusted replacement angle prediction mode, which is an extended angle prediction mode under the wide angle mode. The intra-frame prediction apparatus constructs a prediction mode list for the current decoded block based on the adjusted replacement angle prediction mode to perform intra-frame prediction on the current decoded block. Therefore, in the embodiments of this application, when the intra-frame prediction device determines that the aspect ratio of the current decoded block is different from that of the reference decoded block, the intra-frame prediction device adjusts the replacement angle prediction mode of the reference decoded block to the nearest direction that is in the same direction as the true prediction direction of the adjacent adjustment unit, or the opposite direction with the same angle, and adds it to the MPM list, thereby improving the accuracy of the prediction angle. When performing luminance intra-frame prediction through the MPM list, the accuracy of intra-frame prediction will be greatly improved, thereby improving coding efficiency.

Claims

1. An intra-frame prediction method applied to a decoder, wherein, The method includes: Analyze the bitstream to determine the aspect ratio of the current decoded block and the reference block associated with the current decoded block; When the aspect ratio of the current decoded block is different from that of the reference block, the replacement angle prediction mode corresponding to the reference block is adjusted to obtain the adjusted replacement angle prediction mode, which is an extended angle prediction mode under the wide angle mode. Based on the adjusted replacement angle prediction mode, a prediction mode list for the current decoding block is constructed, and the intra-frame prediction value of the current decoding block is determined. The prediction mode list is the most probable prediction mode (MPM) list. The context model is used to decode the index of the prediction mode of the current decoding block in the MPM list. The adjustment of the replacement angle prediction mode corresponding to the reference block includes: The replacement angle prediction mode corresponding to the reference block is adjusted to the nearest direction that is in the same direction as the true prediction direction of the adjacent block, or the opposite direction with the same angle.

2. The method according to claim 1, wherein, The step of adjusting the replacement angle prediction mode corresponding to the reference block to obtain the adjusted replacement angle prediction mode includes: Based on the reference block, a first angle prediction mode and a second angle prediction mode are determined; wherein, the first angle prediction mode is the maximum angle prediction mode corresponding to the aspect ratio of the current decoding block, and the second angle prediction mode is the minimum angle prediction mode corresponding to the aspect ratio of the current decoding block. The replacement angle prediction mode is adjusted based on the first angle prediction mode and the second angle prediction mode.

3. An intra-frame prediction method applied to an encoder, wherein, The method includes: Analyze the bitstream to determine the aspect ratio of the current coded block and the reference block associated with the current coded block; When the aspect ratio of the current coding block is different from that of the reference block, the replacement angle prediction mode corresponding to the reference block is adjusted to obtain the adjusted replacement angle prediction mode, which is an extended angle prediction mode under the wide angle mode. Based on the adjusted replacement angle prediction mode, a prediction mode list for the current coding block is constructed, and the intra-frame prediction value of the current coding block is determined. The prediction mode list is the most probable prediction mode (MPM) list, and a context model is used to encode the index of the prediction mode of the current coding block in the MPM list. The adjustment of the replacement angle prediction mode corresponding to the reference block includes: The replacement angle prediction mode corresponding to the reference block is adjusted to the nearest direction that is in the same direction as the true prediction direction of the adjacent block, or the opposite direction with the same angle.

4. The method according to claim 3, wherein, The step of adjusting the replacement angle prediction mode corresponding to the reference block to obtain the adjusted replacement angle prediction mode includes: Based on the reference block, a first angle prediction mode and a second angle prediction mode are determined; wherein, the first angle prediction mode is the maximum angle prediction mode corresponding to the aspect ratio of the current decoding block, and the second angle prediction mode is the minimum angle prediction mode corresponding to the aspect ratio of the current decoding block. The replacement angle prediction mode is adjusted based on the first angle prediction mode and the second angle prediction mode.

5. An intra-frame prediction device, wherein, The intra-frame prediction device includes a processor, a memory storing processor-executable instructions, a communication interface, and a bus for connecting the processor, the memory, and the communication interface. When the instructions are executed, the processor performs the following steps: Analyze the bitstream to determine the aspect ratio of the current decoded block and the reference block associated with the current decoded block; When the aspect ratio of the current decoded block is different from that of the reference block, the replacement angle prediction mode corresponding to the reference block is adjusted to the nearest direction that is in the same direction as the true prediction direction of the adjacent block, or the opposite direction with the same angle, so as to adjust the replacement angle prediction mode corresponding to the reference block and obtain the adjusted replacement angle prediction mode. The replacement angle prediction mode is an extended angle prediction mode under the wide angle mode. Based on the adjusted replacement angle prediction mode, a prediction mode list for the current decoding block is constructed, and the intra-frame prediction value of the current decoding block is determined. The prediction mode list is the most probable prediction mode (MPM) list. A context model is used to decode the index of the prediction mode of the current decoding block in the MPM list.

6. The apparatus according to claim 5, wherein, The processor adjusts the replacement angle prediction mode corresponding to the reference block to obtain the adjusted replacement angle prediction mode, specifically including: Based on the reference block, a first angle prediction mode and a second angle prediction mode are determined; wherein, the first angle prediction mode is the maximum angle prediction mode corresponding to the aspect ratio of the current decoding block, and the second angle prediction mode is the minimum angle prediction mode corresponding to the aspect ratio of the current decoding block. The replacement angle prediction mode is adjusted based on the first angle prediction mode and the second angle prediction mode.

7. An intra-frame prediction apparatus, wherein, The intra-frame prediction device includes a processor, a memory storing processor-executable instructions, a communication interface, and a bus for connecting the processor, the memory, and the communication interface. When the instructions are executed, the processor performs the following steps: Analyze the bitstream to determine the aspect ratio of the current coded block and the reference block associated with the current coded block; When the aspect ratio of the current coding block is different from that of the reference block, the replacement angle prediction mode corresponding to the reference block is adjusted to the nearest direction that is in the same direction as the true prediction direction of the adjacent block, or the opposite direction with the same angle, so as to adjust the replacement angle prediction mode corresponding to the reference block and obtain the adjusted replacement angle prediction mode. The replacement angle prediction mode is an extended angle prediction mode under the wide angle mode. Based on the adjusted replacement angle prediction mode, a prediction mode list for the current coding block is constructed, and the intra-frame prediction value of the current coding block is determined. The prediction mode list is the most probable prediction mode (MPM) list, and a context model is used to encode the index of the prediction mode of the current coding block in the MPM list.

8. The apparatus according to claim 7, wherein, The processor adjusts the replacement angle prediction mode corresponding to the reference block to obtain the adjusted replacement angle prediction mode, specifically including: Based on the reference block, a first angle prediction mode and a second angle prediction mode are determined; wherein, the first angle prediction mode is the maximum angle prediction mode corresponding to the aspect ratio of the current decoding block, and the second angle prediction mode is the minimum angle prediction mode corresponding to the aspect ratio of the current decoding block. The replacement angle prediction mode is adjusted based on the first angle prediction mode and the second angle prediction mode.

9. A computer-readable storage medium having a program stored thereon for use in an intra-frame prediction apparatus, wherein, When the program is executed by the processor, it implements the method as described in any one of claims 1-2.

10. A computer-readable storage medium having a program stored thereon for use in an intra-frame prediction apparatus, wherein, When the program is executed by the processor, it implements the method as described in any one of claims 3-4.

11. A computer-readable storage medium storing a computer program and a bit stream thereon, characterized in that, When executed by a processor, the computer program implements the steps of the intra-frame prediction method according to any one of claims 3-4 to generate the bitstream.

Images