Intra prediction method and apparatus, and computer-readable storage medium

Abstract

Provided are an intra prediction method and apparatus, and a computer-readable storage medium. The method comprises: acquiring a first reference sample set corresponding to the current processing block, wherein the first reference sample set includes at least one of a reference row adjacent to the current processing block and a reference column adjacent to the current processing block; selecting, based on a pre-set selection method, a second reference sample set from the first reference sample set, wherein the second reference sample set includes at least one reference sample in the reference row adjacent to the current processing block or the reference column adjacent to the current processing block; obtaining, based on the second reference sample set, a prediction value of the current processing block; and performing, based on the prediction value, intra prediction on the current processing block. FIG. 5

Description

Intra-frame prediction method and apparatus, computer-readable storage medium Technical Field

[0001] This application relates to video encoding and decoding technology, including but not limited to intra-frame prediction methods and apparatus, and computer-readable storage media. Background Technology

[0002] In multi-functional video codecs, when performing intra-frame prediction on the current processing block, the optimal prediction mode (i.e., the prediction mode written to the bitstream) of spatially corresponding or adjacent prediction blocks that have already completed intra-frame prediction (also known as previously reconstructed blocks), the derived mode of the optimal direction of the previously reconstructed blocks, and some fixed intra-frame prediction modes are typically combined as a candidate prediction mode set for the current processing block. Intra-frame prediction is then performed on the current processing block based on multiple candidate prediction modes in this set. Traditional intra-frame prediction modes include Direct Current (DC) mode, Planar mode, and angular prediction mode. Here, we will further discuss the DC mode.

[0003] Currently, the process of intra-frame prediction of the current processing block using DC mode is as follows: the adjacent previous row pixel unit and the left column pixel unit of the current processing block are used as reference pixel units, the DC coefficient is obtained by averaging the reference pixel values ​​of the reference pixel units, and the DC coefficient is used as the prediction value of the current processing block to construct the prediction value of the current processing block.

[0004] However, since the DC coefficients mentioned above are obtained by averaging neighboring reference pixel units, the larger the processing block size, the more reference pixel units are needed to construct the DC coefficients, and the higher the complexity of averaging. Therefore, the computational complexity increases with the increase of the processing block size.

[0005] Summary of the Invention

[0006] The embodiments of this application provide an intra-frame prediction method and apparatus, as well as a computer-readable storage medium, which can reduce the computational load and complexity of intra-frame prediction, thereby improving encoding and decoding efficiency.

[0007] In a first aspect, embodiments of this application provide an intra-frame prediction method, the method comprising:

[0008] Obtain a first set of reference pixels corresponding to the current processing block; wherein the first set of reference pixels is composed of at least one of the reference rows or reference columns adjacent to the current processing block;

[0009] Based on a preset selection method, a second reference pixel set is selected from the first reference pixel set; the second reference pixel set is composed of at least one reference pixel unit in the reference row or reference column adjacent to the current processing block;

[0010] Based on the second reference pixel set, the predicted value of the current processing block is obtained;

[0011] Based on the predicted value, intra-frame prediction is performed on the current processing block.

[0012] In the above scheme, the preset selection method includes at least one of preset position, preset sampling rate, or preset statistical feature.

[0013] In the above scheme, when the preset selection method is the preset position, the step of selecting the second reference pixel set from the first reference pixel set based on the preset selection method includes:

[0014] Determine the sub-reference pixel units at the preset positions for each reference row or each reference column from the first reference pixel set;

[0015] The sub-reference pixel unit is determined as the second reference pixel set.

[0016] In the above scheme, when the preset selection method is the preset sampling rate, the step of selecting the second reference pixel set from the first reference pixel set based on the preset selection method includes:

[0017] According to the preset sampling rate, the reference row or the reference column in the first reference pixel set is downsampled to obtain a downsampled reference pixel unit;

[0018] The downsampled reference pixel unit is determined as the second reference pixel set.

[0019] In the above scheme, when the preset selection method is the preset statistical feature, the step of selecting the second reference pixel set from the first reference pixel set based on the preset selection method includes:

[0020] According to the preset statistical characteristics, the second reference pixel set is selected from the reference rows or reference columns in the first reference pixel set.

[0021] In the above scheme, when the second reference pixel set includes at least two reference pixel units, obtaining the predicted value of the current processing block based on the second reference pixel set includes:

[0022] The mean value is obtained by averaging the pixel values ​​of each of at least two reference pixel units.

[0023] The mean value is determined as the predicted value for the current processing block.

[0024] In the above scheme, when the second reference pixel set includes a reference pixel unit, obtaining the predicted value of the current processing block based on the second reference pixel set includes:

[0025] The pixel value of the reference pixel unit is determined as the predicted value of the current processing block.

[0026] In the above scheme, the preset position is the middle position of the reference row or reference column.

[0027] In the above scheme, the preset sampling rate is one-half.

[0028] In a second aspect, an intra-frame prediction apparatus is characterized by comprising:

[0029] The acquisition unit is configured to acquire a first reference pixel set corresponding to the current processing block; wherein the first reference pixel set is composed of at least one of the reference rows or reference columns adjacent to the current processing block;

[0030] The determining unit is configured to select a second reference pixel set from the first reference pixel set based on a preset selection method; the second reference pixel set consists of at least one reference pixel unit in the reference row or reference column adjacent to the current processing block; and to obtain the predicted value of the current processing block based on the second reference pixel set.

[0031] The prediction unit is configured to perform intra-frame prediction on the current processing block based on the predicted value.

[0032] In the above scheme, the preset selection method includes at least one of preset position, preset sampling rate, or preset statistical feature.

[0033] In the above scheme, when the preset selection method is the preset position,

[0034] The determining unit is specifically configured to determine, from the first reference pixel set, a sub-reference pixel unit that is located at the preset position for each reference row or each reference column; and to determine the sub-reference pixel unit as the second reference pixel set.

[0035] In the above scheme, when the preset selection method is the preset sampling rate,

[0036] The determining unit is specifically configured to downsample the reference row or the reference column in the first reference pixel set according to the preset sampling rate to obtain a downsampled reference pixel unit; and to determine the downsampled reference pixel unit as the second reference pixel set.

[0037] In the above scheme, when the preset selection method is the preset statistical feature,

[0038] The determining unit is specifically configured to select the second reference pixel set from the reference rows or reference columns in the first reference pixel set according to the preset statistical features.

[0039] In the above scheme, when the second reference pixel set includes at least two reference pixel units,

[0040] The determining unit is specifically configured to average the pixel values ​​of each of at least two reference pixel units to obtain an average value; and to determine the average value as the predicted value of the current processing block.

[0041] In the above scheme, when the second reference pixel set includes a reference pixel unit,

[0042] The determining unit is specifically configured to determine the pixel value of the reference pixel unit as the predicted value of the current processing block.

[0043] In the above scheme, the preset position is the middle position of the reference row or reference column.

[0044] In the above scheme, the preset sampling rate is one-half.

[0045] Thirdly, embodiments of this application provide an intra-frame prediction apparatus, including:

[0046] The system includes a memory and a processor, wherein the memory stores a computer program that can run on the processor, and the processor executes the program to implement the intra-frame prediction method described above.

[0047] Fourthly, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described intra-frame prediction method.

[0048] This application provides an intra-frame prediction method and apparatus, and a computer-readable storage medium. The intra-frame prediction apparatus acquires a first reference pixel set corresponding to the current processing block. The first reference pixel set is composed of at least one of the reference rows or reference columns adjacent to the current processing block. Based on a preset selection method, a second reference pixel set is selected from the first reference pixel set. The second reference pixel set is composed of at least one reference pixel unit from the reference rows or reference columns adjacent to the current processing block. Based on the second reference pixel set, a predicted value for the current processing block is obtained. Based on the predicted value, intra-frame prediction is performed on the current processing block. By employing the above technical implementation, since the intra-frame prediction apparatus selects a portion of reference pixel units from the reference rows or reference columns adjacent to the current processing block and obtains the predicted value based on these reference pixel units, the number of reference pixel units is reduced, thus decreasing the computational load and complexity of intra-frame prediction and improving encoding / decoding efficiency. Attached Figure Description

[0049] Figure 1 is a schematic diagram illustrating the relationship between the current processing block and the reference pixel set.

[0050] Figure 2A is a schematic diagram showing the relationship between the current processing block and the reference pixel set.

[0051] Figure 2B is a schematic diagram showing the relationship between the current processing block and the reference pixel set.

[0052] Figure 3 is a schematic block diagram of a video decoding system provided in an embodiment of this application;

[0053] Figure 4A is a schematic diagram of the composition structure of the video encoder provided in this embodiment of the present application;

[0054] Figure 4B is a schematic diagram of the composition structure of the video decoder provided in this embodiment of the present application;

[0055] Figure 5 is a flowchart of an intra-frame prediction method provided in an embodiment of this application;

[0056] Figure 6 is a flowchart of an intra-frame prediction method provided in an embodiment of this application;

[0057] Figure 7 is a schematic diagram illustrating the relationship between the current processing block and the reference pixel set in an exemplary embodiment of this application.

[0058] Figure 8 is a schematic diagram of the relationship between the current processing block and the reference pixel set in an exemplary embodiment of this application.

[0059] Figure 9 is a schematic diagram illustrating the relationship between the current processing block and the reference pixel set in an exemplary embodiment of this application.

[0060] Figure 10 is a schematic diagram illustrating the relationship between the current processing block and the reference pixel set in an exemplary embodiment of this application.

[0061] Figure 11 is a flowchart of an intra-frame prediction method provided in an embodiment of this application;

[0062] Figure 12 is a schematic diagram illustrating the relationship between the current processing block and the reference pixel set in an exemplary embodiment of this application.

[0063] Figure 13 is a schematic diagram illustrating the relationship between the current processing block and the reference pixel set in an exemplary embodiment of this application.

[0064] Figure 14 is a flowchart of an intra-frame prediction method provided in an embodiment of this application;

[0065] Figure 15 is a schematic diagram of an intra-frame prediction device provided in an embodiment of this application;

[0066] Figure 16 is a schematic diagram of an intra-frame prediction device provided in an embodiment of this application. Detailed Implementation

[0067] In order to gain a more detailed understanding of the features and technical content of the embodiments of this application, the implementation of the embodiments of this application will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference and illustration only and are not intended to limit the embodiments of this application.

[0068] Let's first introduce the concepts of intra-frame prediction and video encoding / decoding.

[0069] The main function of predictive encoding and decoding is to construct the predicted value of the current processing block using the reconstructed image that is already available in space or time during video encoding and decoding, and only transmit the difference between the original value and the predicted value, so as to reduce the amount of data transmitted.

[0070] The main function of intra-frame prediction is to construct the predicted value of the current processing block using the pixel units in the previous row and the pixel units in the left column of the current processing block. As shown in Figure 1, each pixel unit of the current processing block 101 is predicted using the recovered neighboring pixels around the current processing block 101 (i.e., the pixel units in the previous row 102 and the pixel units in the left column 103 adjacent to the current processing block).

[0071] In this embodiment, intra-frame prediction for processing blocks in relatively flat areas can be performed using DC mode (the square block DC mode shown in Figure 2A and the rectangular block DC mode shown in Figure 2B) and PLANAR mode. In DC mode, the average pixel values ​​(e.g., chroma or luminance values) corresponding to the pixel units in the previous row or left column are used to fill the entire current processing block. In PLANAR mode, a gradient is used to fill the current processing block.

[0072] In Figure 2A, region 1 represents adjacent reconstruction reference pixel units.

[0073] It should be noted that Versatile Video Coding (VVC) and previous video coding technologies support various coding unit partitions such as quadtrees, binary trees, and ternary trees, resulting in rectangular blocks. Therefore, when performing DC mode prediction, if the block is divided into rectangular blocks, the prediction process is the same as shown in Figure 2A, using the reference pixel set of the left column (reference column) and the previous row (reference row) of the current processing block for prediction. The DC mode of a rectangular block is shown in Figure 2B. For rectangular blocks, the DC coefficients are obtained using either the reference pixel unit of the long side (i.e., region 2) or the reference pixel unit of the short side. The advantage of using only the reference pixel unit of the long side is that it avoids the division operation when calculating the average pixel value, and the encoding and decoding quality remains almost unchanged. For example, assuming the current processing block size is 8x4, considering that the number of reference pixel units on the long side, 8, is a power of 2, the averaging can be directly achieved through a shift operation, thereby reducing computational complexity.

[0074] Based on the above concepts, this application provides a network architecture for a video encoding / decoding system including an intra-frame prediction method. Figure 3 is a schematic diagram of the network architecture of the video encoding / decoding system according to this application. As shown in Figure 3, the network architecture includes one or more electronic devices 11 to 1N and a communication network 01. The electronic devices 11 to 1N can perform video interaction through the communication network 01. During implementation, the electronic devices can be various types of devices with video encoding / decoding capabilities. For example, the electronic devices may include mobile phones, tablets, personal computers, personal digital assistants, navigators, digital phones, video phones, televisions, sensing devices, servers, etc., and this application does not impose any limitations. The intra-frame prediction device in this application embodiment can be one of the aforementioned electronic devices.

[0075] The electronic device in this application embodiment has video encoding and decoding functions, and generally includes a video encoder and a video decoder.

[0076] For example, referring to Figure 4A, the video encoder 21 comprises the following structures: a transform and quantization unit 211, an intra-frame estimation unit 212, an intra-frame prediction unit 213, a motion compensation unit 214, a motion estimation unit 215, an inverse transform and inverse quantization unit 216, a filter control and analysis unit 217, a filtering unit 218, an entropy coding unit 219, and a decoded image buffer unit 210. The filtering unit 218 can implement deblocking filtering and Sample Adaptive Offset (SAO) filtering, while the entropy coding unit 219 can implement header information encoding and Context-based Adaptive Binary Arithmatic Coding (CABAC). For the input source video data, the encoding is performed using a coding tree. The partitioning of a Unit (CTU) yields a block to be encoded in the current video frame. After performing intra-frame prediction or inter-frame prediction on this block, the resulting residual information is transformed by the transform and quantization unit 211. This transformation includes converting 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 212 and intra-frame prediction unit 213 perform intra-frame prediction on the block to be encoded, for example, determining the intra-frame prediction mode for encoding the block. Motion compensation unit 214 and motion estimation unit 215 perform inter-frame prediction coding of the block to be encoded relative to one or more blocks in one or more reference frames to provide temporal prediction information. The motion estimation unit 215 estimates motion vectors, which can estimate the motion of the block to be encoded. The motion compensation unit 214 then performs motion compensation based on these motion vectors. After determining the intra-frame prediction mode, the intra-frame prediction unit... 213 is also used to provide the selected intra-frame prediction data to the entropy coding unit 219, and the motion estimation unit 215 also sends the calculated motion vector data to the entropy coding unit 219; in addition, the inverse transform and inverse quantization unit 216 is used to reconstruct the block to be coded, reconstructing the residual block in the pixel domain, the reconstructed residual block is removed by the filter control analysis unit 217 and the filtering unit 218 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 entropy coding unit 219 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-frame prediction mode, and output the bitstream of the video data; while the decoding image buffer unit 210 is used to store the reconstructed video coding block for prediction reference.As video encoding progresses, new reconstructed video encoding blocks are continuously generated, and these reconstructed video encoding blocks are stored in the decoding image buffer unit 210.

[0077] The video decoder 22, corresponding to the video encoder 21, has the following structure as shown in Figure 4B: it includes an entropy decoding unit 221, an inverse transform and inverse quantization unit 222, an intra-frame prediction unit 223, a motion compensation unit 224, a filtering unit 225, and a decoded image buffer unit 226. The entropy decoding unit 221 can perform header information decoding and CABAC decoding, while the filtering unit 225 can perform deblocking filtering and SAO filtering. After the input video signal is encoded as shown in Figure 4A, the bitstream of the video signal is output. This bitstream is input to the video decoder 22, first passing through the entropy decoding unit 221 to obtain the decoded transform coefficients. These transform coefficients are then processed by the inverse transform and inverse quantization unit 222 to generate residual blocks in the pixel domain. The intra-frame prediction unit 223 can generate prediction data for the current decoded 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 224 determines the prediction data for the current decoded block by analyzing motion vectors and other associated syntax elements. The system collects information and uses this prediction information to generate a predictive block for the current decoded block being decoded. A decoded video block is formed by summing the residual block from the inverse transform and inverse quantization unit 222 with the corresponding predictive block generated by the intra-frame prediction unit 223 or the motion compensation unit 224. The decoded video block is then filtered by the filtering unit 225 to remove block artifacts, thereby improving video quality. The decoded video block is then stored in the decoded image buffer unit 226, which stores reference images for subsequent intra-frame prediction or motion compensation and is also used for the output display of the video signal.

[0078] Based on this, the technical solution of this application will be further described in detail below with reference to the accompanying drawings and embodiments. The intra-frame prediction method provided in the embodiments of this application can be applied to both the video encoder 21 and the video decoder 22, and the embodiments of this application do not specifically limit it in this regard.

[0079] This application provides an intra-frame prediction method. The method is applied in an intra-frame prediction device. The function implemented by the method can be achieved by the processor in the intra-frame prediction device calling program code. Of course, the program code can be stored in a computer storage medium. It can be seen that the intra-frame prediction device includes at least a processor and a storage medium.

[0080] Figure 5 is a schematic diagram of the implementation flow of the intra-frame prediction method according to an embodiment of this application. As shown in Figure 5, the method includes:

[0081] S101. Obtain the first reference pixel set corresponding to the current processing block; wherein the first reference pixel set is composed of at least one of the reference rows or reference columns adjacent to the current processing block.

[0082] S102. Based on a preset selection method, select a second reference pixel set from the first reference pixel set; the second reference pixel set consists of at least one reference pixel unit in the reference row or reference column adjacent to the current processing block.

[0083] S103. Based on the second reference pixel set, obtain the predicted value of the current processing block.

[0084] S104. Based on the predicted values, perform intra-frame prediction on the current processing block.

[0085] In S101, the current processing block in this embodiment is either a block to be encoded or a block to be decoded. The block to be encoded is the image region in the video frame that currently needs predictive encoding. The block to be decoded is the image region in the video frame that currently needs decoding. The reconstructed pixels outside the current processing block are referred to as reference pixels or reference pixel units because when predicting the current processing block, the attribute information (e.g., luminance components, chrominance components, etc.) of these reconstructed pixels needs to be referenced to predict the pixels to be predicted in the current processing block. Therefore, reconstructed pixels are pixels that have already been predicted.

[0086] In this embodiment of the application, when the intra-frame prediction device encodes and decodes the current processing block, it needs to first obtain the first reference pixel set corresponding to the current processing block, and then perform intra-frame prediction based on the first reference pixel set.

[0087] For example, in DC mode, the first set of reference pixels here consists of at least one of the reference rows or reference columns adjacent to the current processing block. That is, in the embodiments of this application, the first set of reference pixels represents three types: reference row pixels, reference column pixels, or reference row and reference column pixels.

[0088] It should be noted that the reference row pixels and reference column pixels contain multiple pixel units. The selection of the first reference pixel set in this application embodiment can be obtained according to actual regulations and requirements, and this application embodiment does not impose any restrictions.

[0089] For example, the first reference pixel set in FIG1 may include all reconstructed pixels (reference row pixels) in the upper row region 102 of the current processing block 101; or, the first reference pixel set may include all reconstructed pixels (reference row pixels) in the left column region 103 of the current processing block 101; or, the first reference pixel set may include all reconstructed pixels in the upper row region 102 of the current processing block 101 and all reconstructed pixels (i.e., reference row and reference column pixels) in the left column region 103.

[0090] In S102, when the intra-frame prediction device performs intra-frame prediction, a preset selection method is set in advance. The intra-frame prediction device can use the preset selection method to select reference pixel units from the first reference pixel set, that is, select a portion of the reference pixel units from the first reference pixel set, and realize intra-frame prediction of the current processing block based on the portion of reference pixel units.

[0091] Specifically, the intra-frame prediction device uses a preset selection method to select a second reference pixel set from the first reference pixel set; the second reference pixel set consists of at least one reference pixel unit in the reference row or reference column adjacent to the current processing block.

[0092] It should be noted that the first reference pixel set is at least one of the reference rows or reference columns adjacent to the current processing block. Therefore, the reference pixel unit selected from the first reference pixel set is composed of at least one reference pixel unit from the reference rows or reference columns adjacent to the current processing block. That is, the second reference pixel set can be at least one reference pixel unit from a reference row pixel set, or at least one reference pixel unit from a reference column pixel set, or a combination of at least one reference pixel unit from a reference row pixel set and at least one reference pixel unit from a reference column pixel set. The specific combination method of the second reference pixel set can be designed according to the actual situation, and this application embodiment does not impose any limitations.

[0093] In S103 and S104, after obtaining the second reference pixel set, the intra-frame prediction device can obtain the prediction value of the current processing block based on the second reference pixel set, and perform intra-frame prediction on the current processing block based on the prediction value.

[0094] The second reference pixel set includes the pixel identifiers of the reconstructed pixels, such as pixel numbers.

[0095] In this embodiment, since the number of reference pixel units in the second reference pixel set is variable—it can be one or more, i.e., at least two—the intra-frame prediction device obtains the prediction value of the current processing block differently depending on the number of reference pixel units, as follows:

[0096] Method 1: When the second reference pixel set includes at least two reference pixel units, the intra-frame prediction device averages the pixel values ​​of each reference pixel unit in the at least two reference pixel units to obtain the mean value; the mean value is determined as the prediction value of the current processing block.

[0097] Method 2: When the second reference pixel set includes a reference pixel unit, the intra-frame prediction device determines the pixel value of the reference pixel unit as the prediction value of the current processing block.

[0098] For example, in the DC mode, in this embodiment of the application, the intra-frame prediction device needs to first determine the reference pixel unit of the current processing block, that is, the second reference pixel set, and then derive the DC coefficient of the current processing block based on the reference pixel unit in the second reference pixel set, and obtain the prediction value of the current processing block based on the DC coefficient.

[0099] In this embodiment, when the second reference pixel set includes at least two reference pixel units, the intra-frame prediction device averages the pixel values ​​of each of the at least two reference pixel units to obtain a mean value; the mean value is determined as the DC coefficient of the current processing block, i.e., the predicted value of the current processing block. When the second reference pixel set includes one reference pixel unit, the intra-frame prediction device determines the pixel value of the one reference pixel unit as the DC coefficient of the current processing block, i.e., the predicted value of the current processing block.

[0100] Understandably, for large, flat processing blocks, constructing the predicted value of the current processing block using a portion of the existing set of reference pixels reduces algorithm complexity and computational load, thereby improving encoding and decoding efficiency.

[0101] In some embodiments of this application, the preset selection method includes at least one of preset position, preset sampling rate, or preset statistical feature, and the embodiments of this application are not limited thereto.

[0102] Depending on the preset selection method, the set of second reference pixels used in the intra-frame prediction method will be different.

[0103] In some embodiments of this application, as shown in FIG6, when the preset selection method is a preset position, the process of an intra-frame prediction method provided by the embodiments of this application includes:

[0104] S201. Obtain a first reference pixel set corresponding to the current processing block; wherein the first reference pixel set is composed of at least one of the reference rows or reference columns adjacent to the current processing block.

[0105] The implementation of S201 in this embodiment is consistent with the description of the implementation process of S101, and will not be repeated here.

[0106] S202. Determine the sub-reference pixel units at preset positions for each reference row or each reference column from the first reference pixel set.

[0107] S203. The sub-reference pixel unit is determined as the second reference pixel set.

[0108] In S202 and S203, based on the implementation description of S102, the intra-frame prediction device can select sub-reference pixel units at preset positions for reference rows or reference columns in the first reference pixel set as the second reference pixel set. That is, it determines the sub-reference pixel units at preset positions for each reference row or reference column in the first reference pixel set and determines the sub-reference pixel units as the second reference pixel set.

[0109] In this embodiment, when the first reference pixel set is a reference row pixel set, the frame prediction device acquires a reference pixel unit at a preset position in the reference row pixel set as a sub-reference pixel unit, and determines the sub-reference pixel unit as the second reference pixel set. When the first reference pixel set is a reference column pixel set, the frame prediction device acquires a reference pixel unit at a preset position in the reference column pixel set as a sub-reference pixel unit, and determines the sub-reference pixel unit as the second reference pixel set. When the first reference pixel set is a reference row and reference column pixel set, the frame prediction device acquires a first reference pixel unit at a preset position in the reference column pixel set and a second reference pixel unit at a preset position in the reference row pixel set, combines the first reference pixel unit and the second reference pixel unit as a sub-reference pixel unit, and determines the sub-reference pixel unit as the second reference pixel set.

[0110] In the embodiments of this application, the preset position is the middle position of the reference row or reference column, or it can be multiple positions on both sides of the reference row or reference column, etc., and the embodiments of this application do not impose any restrictions.

[0111] For example, the DC mode is used as an example. The intra-frame prediction device selects two sub-reference pixel units from the existing first reference pixel set based on a preset position, and takes the average of these two sub-reference pixel units as the DC coefficient. Assuming the preset position is the middle position of the reference row or reference column, when the current processing block is square, some pixel units in the left column and the upper row of the pixel set at the center of the current processing block are selected as partial reference pixel units. Assuming the current processing block size is NxN, pixel units at positions N / 2 (position index starts from 0) in the left column and the upper row of the pixel set are selected as sub-reference pixel units. For example, in Figure 7, the current block size is 8x8, and the pixels represented by the lines are the existing reference pixel set, i.e., the first reference pixel set. In this case, the pixel unit at index 4 in the left column and the upper row of the pixel set is selected as the sub-reference pixel unit, i.e., the second reference pixel set, used to construct the DC coefficient. When the current processing block is rectangular, the reference pixel unit at position 1 / 2 of the long side of the rectangle is selected as the sub-reference pixel unit. Assuming the current block size is NxM (N>M), the pixel unit at position N / 2 of the length N sides is selected as the sub-reference pixel unit. For example, in Figure 8, the current processing block size is 8x4, and the pixels represented by the lines are the existing reference pixel set, i.e., the first reference pixel set. In this case, the pixel unit at index 4 in the pixel set of the previous row is selected as the sub-reference pixel unit, i.e., the second reference pixel set, to construct the DC coefficients.

[0112] Understandably, the intra-frame prediction method proposed in this application can significantly reduce the computational complexity of DC coefficient derivation, reducing the computational cost by 1 / 2 for square blocks and by 3 / 4 for rectangular blocks. Based on VTM4.0, it can reduce encoding and decoding times while maintaining the same video recovery quality and bitrate.

[0113] It should be noted that, for video images, video frames can be divided into squares or rectangles, etc. In this case, for the first reference pixel set which has both reference row pixels and reference column pixels, the preset position can be different positions for the reference row pixels and reference column pixels, or it can be the same position. This application embodiment does not impose any restrictions.

[0114] In this embodiment, for the current processing block, whether it is a square block or a rectangular block, a combination of sub-reference pixel units at preset positions in the pixel set of the left column and the pixel set of the top row is uniformly selected as the second reference pixel set for constructing DC coefficients; or, for the current processing block, whether it is a square block or a rectangular block, only the first sub-reference pixel unit at a preset position in the pixel set of the left column or the second sub-reference pixel unit at a preset position in the pixel set of the top row is used as the second reference pixel set for constructing DC coefficients.

[0115] For example, as shown in Figures 9 and 10, the combination of sub-reference pixel units at preset positions in the pixel set of the left column and the top row is uniformly selected as the second reference pixel set. For square blocks (Figure 9) and rectangular blocks (Figure 10), the reference pixel units A and B at the center position of the left column and the top column are uniformly selected as the second reference pixel set to construct the DC coefficient.

[0116] For example, only the first sub-reference pixel unit at a preset position in the left column of the pixel set or the second sub-reference pixel unit at a preset position in the previous row of the pixel set is used as the second reference pixel set to construct the DC coefficient, as follows: (1) For a rectangular block, the sub-reference pixel unit at the 1 / 2 position of the long side is selected as the second reference pixel set; for a square block, the combination of sub-reference pixel units at the 1 / 2 position in the previous row or the left column is selected as the second reference pixel set. (2) For a rectangular block, the sub-reference pixel unit at the 1 / 2 position of the short side is selected as the second reference pixel set; for a square block, the combination of sub-reference pixel units at the 1 / 2 position in the previous row or the left column is selected as the second reference pixel set. That is, for a rectangular block, the sub-reference pixel unit at a preset position on one side can be selected as the second reference pixel set, and this application embodiment does not impose any restrictions.

[0117] S204. Based on the second reference pixel set, obtain the predicted value of the current processing block.

[0118] The implementation of S204 in this embodiment is consistent with the description of the implementation process of S103, and will not be repeated here.

[0119] S205. Based on the predicted values, perform intra-frame prediction on the current processing block.

[0120] The implementation of S205 in this embodiment is consistent with the description of the implementation process of S104, and will not be repeated here.

[0121] Understandably, for large, flat processing blocks, constructing the predicted value of the current processing block using a portion of the existing set of reference pixels reduces algorithm complexity and computational load, thereby improving encoding and decoding efficiency.

[0122] In some embodiments of this application, as shown in FIG11, when the preset selection method is a preset sampling rate, the process of an intra-frame prediction method provided by the embodiments of this application includes:

[0123] S301. Obtain a first reference pixel set corresponding to the current processing block; wherein the first reference pixel set is composed of at least one of the reference rows or reference columns adjacent to the current processing block.

[0124] The implementation of S301 in this embodiment is consistent with the description of the implementation process of S101, and will not be repeated here.

[0125] S302. According to the preset sampling rate, the reference rows or reference columns in the first reference pixel set are downsampled to obtain downsampled reference pixel units.

[0126] S303, The downsampling reference pixel unit is determined as the second reference pixel set.

[0127] In S302 and S303, based on the implementation description of S102, the intra-frame prediction device can downsample the reference rows or reference columns in the first reference pixel set according to a preset sampling rate to obtain downsampled reference pixel units, which serve as the second reference pixel set.

[0128] In the embodiments of this application, the preset sampling rate can be one-half or other sampling values, such as three-quarters, two-fifths, etc., and the embodiments of this application do not impose any restrictions.

[0129] For example, the first set of reference pixels is downsampled by 1 / 2, and the DC coefficients are constructed using the downsampled reference pixel units. For the square block, as shown in Figure 12, the lines represent the downsampled reference pixel units C. As shown in Figure 13, the lines represent the downsampled reference pixel units D.

[0130] It should be noted that the preset sampling rate can be understood as a way of selecting a preset position. In this way, the principle of the intra-frame prediction device obtaining the second reference pixel set according to the preset sampling rate is the same as the principle of obtaining the second reference pixel set according to the preset position. This application embodiment does not impose any restrictions.

[0131] S304. Based on the second reference pixel set, obtain the predicted value of the current processing block.

[0132] The implementation of S304 in this embodiment is consistent with the description of the implementation process of S103, and will not be repeated here.

[0133] S305. Based on the predicted value, perform intra-frame prediction on the current processing block.

[0134] The implementation of S305 in this embodiment is consistent with the description of the implementation process of S104, and will not be repeated here.

[0135] Understandably, for large, flat processing blocks, constructing the predicted value of the current processing block using a portion of the existing set of reference pixels reduces algorithm complexity and computational load, thereby improving encoding and decoding efficiency.

[0136] In some embodiments of this application, as shown in FIG14, when the preset selection method is a preset statistical feature, the process of an intra-frame prediction method provided by the embodiments of this application includes:

[0137] S401. Obtain a first reference pixel set corresponding to the current processing block; wherein the first reference pixel set is composed of at least one of the reference rows or reference columns adjacent to the current processing block.

[0138] The implementation of S401 in this embodiment is consistent with the description of the implementation process of S101, and will not be repeated here.

[0139] S402. According to the preset statistical characteristics, select the second reference pixel set from the reference rows or reference columns in the first reference pixel set.

[0140] In this embodiment of the application, the intra-frame prediction device can select a second reference pixel set that satisfies the statistical characteristics from the reference rows or reference columns in the first reference pixel set according to preset statistical characteristics.

[0141] In this embodiment, a preset statistical feature represents the pixel that best represents the adjacent reference pixel unit in the reference row or reference column.

[0142] It should be noted that the preset statistical features can be understood as a method of selecting preset positions. In this way, the principle of the intra-frame prediction device obtaining the second reference pixel set according to the preset statistical features is the same as the principle of obtaining the second reference pixel set according to the preset positions. This application embodiment does not impose any limitations.

[0143] S403. Based on the second reference pixel set, obtain the predicted value of the current processing block.

[0144] The implementation of S403 in this embodiment is consistent with the description of the implementation process of S103, and will not be repeated here.

[0145] S404. Based on the predicted values, perform intra-frame prediction on the current processing block.

[0146] The implementation of S404 in this embodiment is consistent with the description of the implementation process of S104, and will not be repeated here.

[0147] Understandably, for large, flat processing blocks, constructing the predicted value of the current processing block using a portion of the existing set of reference pixels reduces algorithm complexity and computational load, thereby improving encoding and decoding efficiency.

[0148] Based on the foregoing embodiments, this application provides an intra-frame prediction device, which includes the included units and the modules included in each unit. It can be implemented by a processor in the intra-frame prediction device; of course, it can also be implemented by specific logic circuits. In the implementation process, the processor can be a central processing unit (CPU), microprocessor (MPU), digital signal processor (DSP), or field programmable gate array (FPGA), etc.

[0149] As shown in Figure 15, this application embodiment provides an intra-frame prediction device 3, including:

[0150] The acquisition unit 30 is configured to acquire a first reference pixel set corresponding to the current processing block; wherein the first reference pixel set is composed of at least one of the reference rows or reference columns adjacent to the current processing block;

[0151] The determining unit 31 is configured to select a second reference pixel set from the first reference pixel set based on a preset selection method; the second reference pixel set is composed of at least one reference pixel unit in the reference row or reference column adjacent to the current processing block; and to obtain the predicted value of the current processing block based on the second reference pixel set.

[0152] Prediction unit 32 is configured to perform intra-frame prediction on the current processing block based on the predicted value.

[0153] In some embodiments of this application, the preset selection method includes at least one of: preset position, preset sampling rate, or preset statistical feature.

[0154] In some embodiments of this application, when the preset selection method is the preset position,

[0155] The determining unit 31 is specifically configured to determine, from the first reference pixel set, a sub-reference pixel unit located at the preset position for each reference row or each reference column; and to determine the sub-reference pixel unit as the second reference pixel set.

[0156] In some embodiments of this application, when the preset selection method is the preset sampling rate,

[0157] The determining unit 31 is specifically configured to downsample the reference row or the reference column in the first reference pixel set according to the preset sampling rate to obtain a downsampled reference pixel unit; and to determine the downsampled reference pixel unit as the second reference pixel set.

[0158] In some embodiments of this application, when the preset selection method is the preset statistical feature,

[0159] The determining unit 31 is specifically configured to select the second reference pixel set from the reference rows or reference columns in the first reference pixel set according to the preset statistical features.

[0160] In some embodiments of this application, when the second reference pixel set includes at least two reference pixel units,

[0161] The determining unit 31 is specifically configured to average the pixel values ​​of each of at least two reference pixel units to obtain an average value; and to determine the average value as the predicted value of the current processing block.

[0162] In some embodiments of this application, when the second reference pixel set includes a reference pixel unit,

[0163] The determining unit 31 is specifically configured to determine the pixel value of the reference pixel unit as the predicted value of the current processing block.

[0164] In some embodiments of this application, the preset position is the middle position of a reference row or reference column.

[0165] In some embodiments of this application, the preset sampling rate is one-half.

[0166] The descriptions of the above device embodiments are similar to those of the above method embodiments, and have similar beneficial effects. For technical details not disclosed in the device embodiments of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0167] It should be noted that, in the embodiments of this application, if the above-described intra-frame prediction method is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiments of this application, or the part that contributes to the related technology, 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 an electronic device (which may be a mobile phone, tablet computer, personal computer, personal digital assistant, navigator, digital phone, video phone, television, sensor device, server, etc.) to execute all or part of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memory (ROM), magnetic disks, or optical disks. Thus, the embodiments of this application are not limited to any specific hardware and software combination.

[0168] In practical applications, as shown in Figure 16, this embodiment of the application provides an intra-frame prediction device, including:

[0169] The memory 33 stores a computer program that can run on the processor 34. When the processor 34 executes the program, it implements the steps in the intra-frame prediction method provided in the above embodiments.

[0170] Accordingly, embodiments of this application provide a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps in the intra-frame prediction method provided in the above embodiments.

[0171] It should be noted that the descriptions of the storage medium and device embodiments above are similar to those of the method embodiments above, and have similar beneficial effects. For technical details not disclosed in the storage medium and device embodiments of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0172] The above description is merely an embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims. Industrial applicability

[0173] In this embodiment of the application, when the intra-frame prediction device performs intra-frame prediction on the current processing block, it selects a portion of reference pixel units from the reference rows or reference columns adjacent to the current processing block and obtains the prediction value of the current processing block based on the portion of reference pixel units. The number of reference pixel units is small, which reduces the computational load and complexity of intra-frame prediction, thereby improving the encoding and decoding efficiency.

Claims

1. An intra-frame prediction method, characterized in that, The method includes: Obtain a first set of reference pixels corresponding to the current processing block; wherein the first set of reference pixels is composed of at least one of the reference rows or reference columns adjacent to the current processing block; Based on a preset selection method, a second reference pixel set is selected from the first reference pixel set; the second reference pixel set is composed of at least one reference pixel unit in the reference row or reference column adjacent to the current processing block; Based on the second reference pixel set, the predicted value of the current processing block is obtained; Based on the predicted value, intra-frame prediction is performed on the current processing block.

2. The method according to claim 1, characterized in that, The preset selection method includes at least one of the following: preset position, preset sampling rate, or preset statistical feature.

3. The method according to claim 2, characterized in that, When the preset selection method is the preset position, the step of selecting the second reference pixel set from the first reference pixel set based on the preset selection method includes: Determine the sub-reference pixel units at the preset positions for each reference row or each reference column from the first reference pixel set; The sub-reference pixel unit is determined as the second reference pixel set.

4. The method according to claim 2, characterized in that, When the preset selection method is the preset sampling rate, the step of selecting the second reference pixel set from the first reference pixel set based on the preset selection method includes: According to the preset sampling rate, the reference row or the reference column in the first reference pixel set is downsampled to obtain a downsampled reference pixel unit; The downsampled reference pixel unit is determined as the second reference pixel set.

5. The method according to claim 2, characterized in that, When the preset selection method is the preset statistical feature, the step of selecting the second reference pixel set from the first reference pixel set based on the preset selection method includes: According to the preset statistical characteristics, the second reference pixel set is selected from the reference rows or reference columns in the first reference pixel set.

6. The method according to any one of claims 1 to 5, characterized in that, When the second reference pixel set includes at least two reference pixel units, obtaining the prediction value of the current processing block based on the second reference pixel set includes: The mean value is obtained by averaging the pixel values ​​of each of at least two reference pixel units. The mean value is determined as the predicted value for the current processing block.

7. The method according to any one of claims 1 to 5, characterized in that, When the second reference pixel set includes a reference pixel unit, obtaining the prediction value of the current processing block based on the second reference pixel set includes: The pixel value of the reference pixel unit is determined as the predicted value of the current processing block.

8. The method according to claim 2, characterized in that, The preset position is the middle position of the reference row or reference column.

9. The method according to claim 2, characterized in that, The preset sampling rate is one-half.

10. An intra-frame prediction device, characterized in that, include: The acquisition unit is configured to acquire a first reference pixel set corresponding to the current processing block; wherein the first reference pixel set is composed of at least one of the reference rows or reference columns adjacent to the current processing block; The determining unit is configured to select a second reference pixel set from the first reference pixel set based on a preset selection method; the second reference pixel set consists of at least one reference pixel unit in the reference row or reference column adjacent to the current processing block; and to obtain the predicted value of the current processing block based on the second reference pixel set. The prediction unit is configured to perform intra-frame prediction on the current processing block based on the predicted value.

11. The apparatus according to claim 10, characterized in that, The preset selection method includes at least one of the following: preset position, preset sampling rate, or preset statistical feature.

12. The apparatus according to claim 11, characterized in that, When the preset selection method is the preset position... The determining unit is specifically configured to determine, from the first reference pixel set, a sub-reference pixel unit that is located at the preset position for each reference row or each reference column; and to determine the sub-reference pixel unit as the second reference pixel set.

13. The apparatus according to claim 11, characterized in that, When the preset selection method is the preset sampling rate The determining unit is specifically configured to downsample the reference row or the reference column in the first reference pixel set according to the preset sampling rate to obtain a downsampled reference pixel unit. And the downsampled reference pixel unit is determined as the second reference pixel set.

14. The apparatus according to claim 11, characterized in that, When the preset selection method is the preset statistical feature... The determining unit is specifically configured to select the second reference pixel set from the reference rows or reference columns in the first reference pixel set according to the preset statistical features.

15. The apparatus according to any one of claims 10 to 14, characterized in that, When the second reference pixel set includes at least two reference pixel units The determining unit is specifically configured to average the pixel values ​​of each of at least two reference pixel units to obtain an average value; and to determine the average value as the predicted value of the current processing block.

16. The apparatus according to any one of claims 10 to 14, characterized in that, When the second set of reference pixels includes a reference pixel unit The determining unit is specifically configured to determine the pixel value of the reference pixel unit as the predicted value of the current processing block.

17. The apparatus according to claim 11, characterized in that, The preset position is the middle position of the reference row or reference column.

18. The apparatus according to claim 11, characterized in that, The preset sampling rate is one-half.

19. An intra-frame prediction device, characterized in that, include: A memory and a processor, the memory storing a computer program executable on the processor, the processor executing the program to implement the intra-frame prediction method of any one of claims 1 to 9.

20. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the intra-frame prediction method according to any one of claims 1 to 9.