Decoder-side intra mode derivation for most probable mode list construction in video coding

Abstract

A method of decoding video data includes deriving an intra mode list using reconstructed samples of neighboring blocks for a current block of video data and using decoder-side intra mode derivation (DIMD), constructing a most probable mode (MPM) list for the current block, wherein constructing the MPM list includes inserting at least one intra mode from the derived intra mode list into the MPM list, and predicting the current block using a candidate selected from the constructed MPM list.

Description

[0001] This application claims priority to U.S. Patent Application No. 17 / 502,875, filed October 15, 2021, and U.S. Provisional Application No. 63 / 129,004, filed December 22, 2020, the entire contents of which are incorporated herein by reference. U.S. Patent Application No. 17 / 502,875, filed October 15, 2021, claims the benefit of U.S. Provisional Application No. 63 / 129,004, filed December 22, 2020. Technical Field

[0002] This disclosure relates to video encoding and video decoding. Background Technology

[0003] Digital video capabilities can be incorporated into a wide range of devices, including digital televisions, digital live broadcast systems, wireless broadcasting systems, personal digital assistants (PDAs), laptops or desktop computers, tablets, e-book readers, digital cameras, digital recording devices, digital media players, video game devices, video game consoles, cellular or satellite radio phones, so-called "smartphones," video conferencing equipment, video streaming devices, and more. Digital video devices implement video decoding technologies, such as those described in standards defined by MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264 / MPEG-4 Part 10, Advanced Video Decoding (AVC), ITU-T H.265 / High-Efficiency Video Decoding (HEVC), and extensions to these standards. By implementing such video decoding technologies, video devices can more efficiently send, receive, encode, decode, and / or store digital video information.

[0004] Video decoding techniques include spatial (intra-picture) prediction and / or temporal (inter-picture) prediction to reduce or remove inherent redundancy in video sequences. For block-based video decoding, video slices (e.g., video pictures or portions of video pictures) can be divided into video blocks, which may also be referred to as decoding tree units (CTUs), decoding units (CUs), and / or decoding nodes. Video blocks in an intra-frame decoded (I) slice of a picture are encoded using spatial predictions about reference samples in neighboring blocks within the same picture. Video blocks in an inter-frame decoded (P or B) slice of a picture can use spatial predictions about reference samples in neighboring blocks within the same picture, or temporal predictions about reference samples in other reference pictures. A picture may be referred to as a frame, and a reference picture may be referred to as a reference frame. Summary of the Invention

[0005] Typically, this disclosure describes techniques for decoding video data using derived intra-mode bias (DIMD). To perform intra-mode decoding without utilizing DIMD, a video decoder (e.g., a video encoder and / or video decoder) can construct a list of intra-mode candidates (e.g., a most probable mode (MPM) list) and a signal indicating which candidate in the list is used as the intra-mode for the current block. To perform intra-mode decoding using DIMD, the video decoder can implicitly derive the intra-mode for the current block based on reconstructed samples from neighboring blocks and predict the current block based on a mix of the derived intra-modes. The video encoder can determine whether to use DIMD to predict the current block and provides a signal indicating syntax elements that indicate whether the current block is predicted using DIMD or using a list (e.g., not predicted using DIMD). However, implementations of DIMD can offer various advantages. For example, DIMD prediction implementations can involve the video encoder determining whether to perform intra-mode prediction using a mix of modes derived from multiple DIMDs or a single mode. Such implementations can sacrifice robustness, where the best prediction pattern is one of the patterns derived from DIMD, but the best prediction may come from only a single prediction (e.g., the opposite of a mixed prediction from patterns derived from DIMD).

[0006] According to one or more techniques of this disclosure, a video decoder (e.g., a video encoder and / or video decoder) may include one or more DIMD-derived modes as candidate intra-frame modes in a most probable mode (MPM) list. For example, the video decoder may perform DIMD mode derivation to derive one or more DIMD modes and include one or more derived DIMD modes in a list of intra-frame mode candidates. The video decoder may signal which candidate in the list will be used as the intra-frame mode for the current block. For example, if a particular DIMD mode among the DIMD modes included in the list is the best prediction mode, the video encoder may signal that that particular DIMD mode will be used as the intra-frame mode for the current block. The use of more best modes can reduce the number of bits used to represent video data. Thus, in this way, the techniques of this disclosure can improve decoding efficiency.

[0007] In one example, a method for decoding video data includes: for the current block of video data and using DIMD to derive a list of intra-modes using reconstructed samples from neighboring blocks; constructing a list of most probable modes (MPMs) for the current block, wherein constructing the MPM list includes inserting at least one intra-mode from the derived list of intra-modes into the MPM list; and using candidates selected from the constructed list of MPMs to predict the current block.

[0008] In another example, an encoding method includes: for the current block of video data and using DIMD to derive an intra-mode list using reconstructed samples from neighboring blocks; constructing an MPM list for the current block, wherein constructing the MPM list includes inserting at least one intra-mode from the derived intra-mode list into the MPM list; for the current block and selecting a candidate intra-mode from the MPM list; and encoding one or more syntax elements of the specified candidate intra-mode for the current block.

[0009] In another example, an apparatus for decoding video data includes: a memory configured to store video data; and one or more processors implemented in circuitry and configured to: derive an intra-mode list using reconstructed samples of neighboring blocks for a current block of video data and using DIMD; construct an MPM list for the current block, wherein constructing the MPM list includes inserting at least one intra-mode from the derived intra-mode list into the MPM list; and predict the current block using candidates selected from the constructed MPM list.

[0010] In another example, an apparatus for encoding video data includes: a memory configured to store video data; and one or more processors implemented in circuitry and configured to: derive an intra-mode list for a current block of video data using reconstructed samples from neighboring blocks with DIMD; construct an MPM list for the current block, wherein constructing the MPM list includes inserting at least one intra-mode from the derived intra-mode list into the MPM list; select candidate intra-modes for the current block from the MPM list; and encode one or more syntax elements of the specified candidate intra-modes for the current block.

[0011] Details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description, the figures, and the claims. Attached Figure Description

[0012] Figure 1 This is a block diagram illustrating an example video encoding and decoding system capable of performing the techniques of this disclosure.

[0013] Figure 2A and Figure 2B This is a conceptual diagram illustrating a quadtree-binary tree (QTBT) structure and its corresponding decoding tree unit (CTU).

[0014] Figure 3 This is a block diagram illustrating an example video encoder that can perform the techniques of this disclosure.

[0015] Figure 4This is a block diagram illustrating an example video decoder that can perform the techniques of this disclosure.

[0016] Figure 5 This is a conceptual diagram illustrating the set of pixels on which a video decoder can perform gradient analysis.

[0017] Figure 6 This is a graphic illustrating an example of orientation index mapping using horizontal and vertical gradients.

[0018] Figure 7 It is a graph illustrating the choice between two most likely predictive patterns.

[0019] Figure 8 This is a conceptual diagram illustrating an example prediction of a decoder-side intra-mode derivation (DIMD) mode.

[0020] Figure 9A This is a flowchart illustrating an example technique used for intra-block decoding.

[0021] Figure 9B This is a flowchart illustrating an example technique for intra-block decoding using DIMD.

[0022] Figure 10 This is a flowchart illustrating an example technique for intra-block decoding constructed using a list of most probable DIMD modes (MPMs) according to one or more techniques disclosed herein.

[0023] Figure 11 This is a flowchart illustrating an example technology constructed from a list of one or more technologies according to this disclosure.

[0024] Figure 12 This is a flowchart illustrating an example technique for deriving an intra-frame mode list via DIMD according to one or more techniques of this disclosure.

[0025] Figure 13 This is a conceptual diagram illustrating an example of a neighboring block.

[0026] Figure 14 This is a flowchart illustrating an example technique for adding DIMD-derived patterns to an MPM list according to one or more techniques of this disclosure.

[0027] Figure 15 This is a flowchart illustrating an example method for encoding the current block according to the technology of this disclosure.

[0028] Figure 16 This is a flowchart illustrating an example method for decoding the current block according to the technology of this disclosure.

[0029] Figure 17This is a flowchart illustrating an example technique for encoding video data using DIMD, based on one or more techniques according to this disclosure.

[0030] Figure 18 This is a flowchart illustrating an example technique for decoding video data using DIMD, based on one or more techniques according to this disclosure. Detailed Implementation

[0031] Video decoding standards include ITU-T H.261, ISO / IEC MPEG-1 Visual, ITU-T H.262 or ISO / IEC MPEG-2 Visual, ITU-T H.263, ISO / IEC MPEG-4 Visual (MPEG-4 Part 2), ITU-T H.264 (also known as ISO / IEC MPEG-4 AVC) (including its Scalable Video Decoding (SVC) and Multi-View Video Decoding (MVC) extensions), ITU-T H.265 with its extensions (also known as ISO / IEC MPEG-4 HEVC), and video decoding (VVC) standardization activities (also known as ITU-T H.266).

[0032] Decoder-side intra-frame mode derivation (DIMD) is presented as a decoding tool for intra-frame prediction in the following document: JVET-L0164, "CE3 Related: Decoder-side Intra-frame Mode Derivation," from the 12th meeting of the Joint Video Experts Group (JVET) of ITU-T SG 16WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11 held in Macao, China, from 3 to 12 October 2018 (this document is available at https: / / jvet-experts.org / doc_end_user / documents / 12_Macao / wg11 / JVET-L0164-v2.zip). The document JVET-M0094, "CE3: Decoder-Side Intra-Frame Mode Derivation (Tests 3.1.1, 3.1.2, 3.1.3, and 3.1.4), from the 13th meeting of the Joint Video Experts Group (JVET) held in Massachusetts, Morocco, January 9-18, 2019 (available at https: / / jvet-experts.org / doc_end_user / documents / 13_Marrakech / wg11 / JVET-M0094-v2.zip), ITU-T SG 16WP 3, and ISO / IEC JTC 1 / SC 29 / WG, is also relevant. The document JVET-N0342, "Non-CE3: Derivation of Intra-Frame Modes on the Decoder Side Using Predictive Fusion," from the 14th meeting of the Joint Video Experts Group (JVET) of 11 held in Geneva, Switzerland, from 19 to 29 March 2019 (available at https: / / jvet-experts.org / doc_end_user / documents / 14_Geneva / wg11 / JVET-N0342-v5.zip), ITU-T SG 16WP 3, and ISO / IEC JTC 1 / SC 29 / WG, is relevant. The document JVET-O0449, "Non-CE3: Decoder-Side Intra-Frame Mode Derivation Using Planar Predictive Fusion," from the 15th meeting of the Joint Video Experts Group (JVET) held in Gothenburg, Sweden, from July 3 to 12, 2019 (available at https: / / jvet-experts.org / doc_end_user / documents / 15_Gothenburg / wg11 / JVET-O0449-v2.zip), differs from existing intra-frame prediction tools in that, when performing DIMD, the video decoder can not explicitly signal the intra-frame mode. Instead, the video decoder can explicitly derive the intra-frame mode using reconstructed samples from neighboring blocks.The purpose is to improve decoding efficiency by saving signaling in intra-frame mode. Note that DIMD can be applied only to luma. For chroma, the classic intra-frame decoding mode can be applied.

[0033] In some examples, to perform DIMD for the current block, the video decoder can perform gradient computation to derive one or more possible patterns (e.g., M1 and M2). The video decoder can then use each of the derived one or more possible patterns to predict the current block to generate an intermediate prediction block, and generate an output prediction based on the intermediate prediction blocks. Details of an example DIMD workflow are as follows:

[0034] The video decoder can perform gradient calculations on reconstructed samples from neighboring blocks. To derive the intra-frame prediction mode of a block, the video decoder can obtain gradients from, for example... Figure 5 The set of neighboring pixels is selected from the nearby, reconstructed brightness samples shown. The video decoder can then apply gradient calculations to the center pixel of each 3×3 window formed by the set of neighboring pixels. Note that if the neighboring pixels are not reconstructed, their gradient values ​​may not be calculated.

[0035] The video decoder can use Sobel filters to perform gradient calculations (denoted as "Mx" and "My"). Point generation between these two filters and each 3×3 window can be performed to derive the horizontal and vertical gradients (denoted as "Gx" and "Gy" respectively). The following can be an example of this filter:

[0036] and

[0037] Gx = Mx * W, and Gy = My * W.

[0038] Video decoders can map gradient values ​​to directions. For example, a video decoder can use G... x and G y To derive the intensity (G) and orientation (O) of each window:

[0039] G = |G x |+|G y | and

[0040] In some examples, to reduce the computational cost of the arctangent (“atan”) operation, the orientation can be represented by the index value of the mapping table “atan” (in the range of 2 to 66), and can be estimated by comparing the mapping table with Gy / Gx; if G y / G xIf the orientation falls within the range of (atan[i], atan[i+1]), then the orientation is assigned the value "i". Note that the intensity G is 0, and O is assigned 0 by default (planar mode). Figure 6 This is a graphic illustrating an example of orientation index mapping using horizontal and vertical gradients.

[0041] exist Figure 6 In the example, for a given 3×3 window, it (e.g., the index value) satisfies:

[0042] angTable

[60] <=Gy / Gx <angTable

[61]

[0043] Orientation can be mapped to predicted direction 60.

[0044] The video decoder can perform a selection between two most probable modes. It can sum the intensity values ​​of each orientation index across the entire 3x3 window. The decoder can then select the two orientations with the highest sums as the two most probable modes (denoted as mode 1 "M1" for the highest sum and mode 2 "M2" for the second highest sum). Note that if all values ​​are zero, the planar mode will be selected. Figure 7 This is a graph illustrating the choice between two of the most likely predictive patterns. Figure 7 In the example, the video decoder can select mode 18 as the first mode M1 and mode 24 as the second mode M2, because 18 and 24 are the sum of the first and second highest amplitudes, respectively.

[0045] Video decoders can perform DIMD prediction. For example... Figure 8 As shown, if the sum of the amplitudes of the second most likely modes is 0 (e.g., if Σ amplitude [M2] == 0), the video decoder can perform normal intra-frame prediction that can be performed using mode M1; otherwise, the video decoder can generate an output prediction block as a weighted sum of the three prediction blocks (M1, M2, and the planar mode). This can be referred to as performing mixed-mode prediction (e.g., because the modes are mixed to generate a single prediction). As an example, the video decoder can generate the weights of each of the prediction blocks (e.g., ω1 for M1, ω2 for M1, and ω3 for the planar mode) according to the following formula.

[0046]

[0047]

[0048]

[0049] The video decoder can generate intermediate prediction blocks based on reference pixels (e.g., Pred1 for M1, Pred2 for M2, and Pred3 for planar modes). The video decoder can then apply weights to the intermediate prediction blocks to generate an output prediction block according to the following formula:

[0050]

[0051] The video decoder can perform signal notification in DIMD mode. Figure 9A This is a flowchart illustrating the example intra-frame decoding process of VVC, and... Figure 9B Is it including DIMD when... Figure 9A Modifications to the process. For example... Figure 9B As shown, the video decoder can parse the DIMD flag. If the DIMD flag is true (e.g., has a value of 1), the video decoder can deduce the intra-prediction mode and perform prediction as explained above. If the DIMD flag is false (e.g., has a value of 0), the video decoder can parse the intra-prediction mode from the bitstream (e.g., construct an MPM list and signal the index entering the MPM list) and perform prediction accordingly. Therefore, in Figure 9B In the example, when the DIMD flag is false, the video decoder may not perform DIMD intra-frame mode derivation.

[0052] The aforementioned DIMD mechanism may have one or more drawbacks. For example, the potential of DIMD may not be fully utilized for various reasons. As an example, DIMD prediction explicitly determines whether the prediction should be a mixed prediction from multiple modes or from a single mode. The aforementioned DIMD mechanism may satisfy robustness, where the optimal prediction mode is the DIMD-derived mode, but the optimal prediction may come from only a single prediction. As another example, in other cases, the optimal intra-frame mode may differ from the DIMD-derived mode, but the difference is small (1 or 2 index differences). Decoding using normal mode indexes costs more bits, but using the DIMD-derived mode does not yield the best RD performance.

[0053] According to one or more techniques disclosed herein, a video decoder (e.g., a video encoder and / or video decoder) can insert DIMD-derived patterns into an MPM list. Thus, the video decoder can decode blocks using DIMD-derived patterns from an intra-frame predicted MPM list.

[0054] Figure 10 This is a flowchart illustrating an example technique for intra-block decoding constructed using a list of most probable DIMD modes (MPMs) according to one or more techniques disclosed herein. Figure 10 and Figure 9BThe comparison yields several differences. For example, compared to the JVETDIMD design (Figure 9), the video decoder implementing the technology of this disclosure ( Figure 10 It can perform DIMD pattern derivation regardless of whether the current block is predicted using DIMD patterns, and the derivation pattern can be added to the MPM list (the MPM list construction process is therefore postponed until after the DIMD process).

[0055] For blocks with a DIMD flag equal to true, the video decoder can perform DIMD prediction as explained above. For blocks with a DIMD flag equal to false, the video decoder can perform normal intra-frame prediction and add the DIMD-derived pattern to the MPM list. Thus, the video decoder can use the DIMD-derived pattern for prediction of blocks with an MPM flag equal to true.

[0056] By execution Figure 10 With this technology, video decoders can further expand the potential of DIMD and can help improve decoding efficiency. Blocks can use DIMD-derived patterns and perform normal prediction by selecting DIMD-derived patterns (or DIMD-derived patterns with offsets) from the MPM list.

[0057] Figure 11 This is a flowchart illustrating an example technique for constructing / deriving an MPM list based on one or more techniques according to this disclosure. Figure 11 The technology can be performed by a video decoder, such as a video encoder 200 and / or a video decoder 300.

[0058] like Figure 11 As shown, in step 1 (1102), the video decoder can derive a list of intra-modes using reconstructed samples from neighboring blocks of the DIMD. In step 2 (1104), the video decoder can add predicted modes from neighboring blocks to the MPM list. In step 3 (1106), the video decoder can add the list of intra-modes derived from the DIMD to the MPM list. In step 4 (1108), the video decoder can add more candidates to the MPM list using a candidate list. The example method adds multiple offsets (in the range of -3 to 3) to all candidates in the list or some candidates in the list (e.g., the first 3 candidates). In step 5 (1110), the video decoder can add (e.g., insert) default intra-modes (DC, planar, horizontal, vertical, etc. modes) to the MPM list.

[0059] thus, Figure 11Steps 4 and / or 5 illustrate the steps in which the video decoder inserts additional intra-mode candidates, which can serve as one or more default candidates, into the MPM list and after at least one intra-mode from the derived intra-mode list. Additionally or alternatively, step 2 may illustrate the steps in which the video decoder inserts one or more intra-mode candidates, which are prediction modes from neighboring blocks of the current block, into the MPM list and before at least one intra-mode from the derived intra-mode list.

[0060] Figure 12 This is a flowchart illustrating an example technique for deriving an intra-frame mode list via DIMD according to one or more techniques of this disclosure. Figure 12 The technology can be performed by a video decoder, such as a video encoder 200 and / or a video decoder 300. Figure 12 The technology can be Figure 11 Example of step 1 (1102) of the technology.

[0061] In 1202, the video decoder can calculate the horizontal and vertical gradient values ​​of each window in the neighboring block as Gx and Gy. Figure 5 The example window is illustrated. In 1204, for each of the sets of horizontal and vertical gradient values, the video decoder can derive the intensity value (|Gx|+|Gy|) and orientation value (Gy / Gx) and map each orientation to an intra-frame mode in the range of 2 to 66 (an example process is given above). The video decoder can also calculate the intensity value as the sum of the absolute values ​​of the horizontal and vertical gradient values, or as the sum of the squares of the horizontal and vertical gradient values. In 1206, for each intra-frame mode, the video decoder can accumulate its corresponding intensity value. In 1208, the video decoder can classify intra-frame modes from high to low based on the accumulated intensity values. The DIMD list can be a list of classified intra-frame modes or only a portion of the list. The DIMD list can exclude intra-frame modes whose sum of intensity values ​​equals 0. The DIMD list can exclude intra-frame modes whose sum of intensity values ​​is less than a threshold. The size of the list can be 0, 1, 2, or larger. If the sum of all intensity values ​​is 0, the first candidate can be set to DC or planar mode.

[0062] As above Figure 11 As shown in 1104, the video decoder can add intra-prediction modes of neighboring blocks to the MPM list. For example... Figure 13 As shown, the example neighboring blocks are the blocks to the left, above, upper left, upper right, and lower left.

[0063] Figure 14 This is a flowchart illustrating an example technique for adding DIMD-derived patterns to an MPM list according to one or more techniques of this disclosure. Figure 14 The technology can be performed by a video decoder, such as a video encoder 200 and / or a video decoder 300. Figure 14 The technology can be Figure 11 Example of step 3 of the technology.

[0064] In step 1402, the video decoder can add a first candidate (denoted as "M1" as explained above) with the highest sum of intensities to the MPM list. In step 1404, the video decoder can determine whether the sum of intensities of the second candidate is 0 (denoted as "M2" as explained above). If it is determined to be 0, the second candidate can be skipped; otherwise, step 1406 is executed. In step 1406, the video decoder can add a second candidate to the MPM list.

[0065] Some example variations and / or alternatives are as follows:

[0066] 1) In step 1404, the video decoder can determine whether the sum of the intensities of the second candidate is less than a threshold. If it is less than the threshold, the video decoder can skip the second candidate; otherwise, the video decoder can add the second candidate to the MPM list construction.

[0067] 2) The condition of 1404 can also be applied to the first candidate.

[0068] 3) Figure 11 The order of the techniques can be switched or interleaved. For example, 1106 can be executed before 1104, or DIMD-derived modes and intra-frame modes from neighboring blocks can be added in an interleaved manner.

[0069] 4) If the decoder executes 1104 before 1102, the intra-mode list derived from DIMD can be trimmed by intra-modes from neighboring blocks; for example, if an intra-mode has already been added to the MPM list in 1104, the intra-mode can be skipped when building the intra-mode list of the DIMD list.

[0070] 5) In 4), if an intra-mode has already been added to the MPM list in 1104, any mode equal to the intra-mode plus an offset (the offset value can be from -3 to 3) will be skipped when building the intra-mode list of the DIMD list.

[0071] 6) The intra-mode list derived from DIMD can also be classified in different orders (e.g., the sum of intensity values ​​from low to high, while keeping the last few candidates).

[0072] 7) Each candidate added to the MPM list can be pruned to prevent duplicate patterns from being added to the MPM list.

[0073] 8) If the first candidate is equal to DC or a planar pattern, it can be skipped.

[0074] Some other example variations and / or alternatives are as follows:

[0075] 1) The DIMD flag can be signaled after the MPM flag.

[0076] 2) The DIMD flag can be signaled as one of the MPM indices.

[0077] 3) There may be only one DIMD-derived pattern added to the MPM list.

[0078] 4) There may be more than two patterns derived from DIMD that are added to the MPM list.

[0079] 5) DIMD can also be applied to chroma blocks.

[0080] 6) The DIMD-derived patterns can also be added to the Chromaticity MPM list.

[0081] 7) Intra-frame prediction may always use a single prediction mode.

[0082] 8) In case 7), the DIMD flag may not be signaled.

[0083] 9) DIMD prediction may use only a single model.

[0084] 10) DIMD prediction may be a hybrid prediction of derivation mode and planar mode.

[0085] 11) DIMD prediction may be a hybrid prediction of (one or more) derivation modes and DC modes.

[0086] 12) DIMD can use predicted samples instead of reconstructed samples for pattern derivation.

[0087] 13) If a block is a DIMD pattern block, its prediction pattern derived from DIMD can be used to construct the MPM list of neighboring blocks.

[0088] 14) If the block is a DIMD mode block, the default mode (DC or plane) can be used to construct the MPM list of neighboring blocks.

[0089] Figure 1This is a block diagram illustrating an example video encoding and decoding system 100 capable of performing the techniques of this disclosure. The techniques of this disclosure generally relate to decoding (encoding and / or decoding) video data. Typically, video data includes any data used for processing video. Therefore, video data can include raw, unencoded video, encoded video, decoded (e.g., reconstructed) video, and video metadata, such as signaling data.

[0090] like Figure 1 As shown, system 100 includes a source device 102, which in this example provides encoded video data to be decoded and displayed by a destination device 116. Specifically, source device 102 provides video data to destination device 116 via computer-readable medium 110. Source device 102 and destination device 116 can include any of a wide range of devices, including: desktop computers, notebook (i.e., laptop) computers, mobile devices, tablet computers, set-top boxes, telephone receivers such as smartphones, televisions, cameras, display devices, digital media players, video game consoles, video streaming devices, broadcast receiver devices, etc. In some cases, source device 102 and destination device 116 may be equipped for wireless communication and may therefore be referred to as wireless communication devices.

[0091] exist Figure 1 In the example, source device 102 includes a video source 104, memory 106, video encoder 200, and output interface 108. Destination device 116 includes an input interface 122, video decoder 300, memory 120, and display device 118. According to this disclosure, the video encoder 200 of source device 102 and the video decoder 300 of destination device 116 can be configured to apply techniques for intra-frame mode derivation used to construct a list of most probable modes. Thus, source device 102 represents an example of a video encoding device, while destination device 116 represents an example of a video decoding device. In other examples, the source device and destination device may include other components or arrangements. For example, source device 102 may receive video data from an external video source such as an external camera. Similarly, destination device 116 may interface with an external display device instead of including an integrated display device.

[0092] like Figure 1The system 100 shown is merely an example. Typically, any digital video encoding and / or decoding device can perform intra-frame mode derivation techniques for constructing a list of most probable modes. Source device 102 and destination device 116 are merely examples of such decoding devices, where source device 102 generates decoded video data for transmission to destination device 116. This disclosure refers to a “decoding” device as a device that performs the decoding (encoding and / or decoding) of data. Thus, video encoder 200 and video decoder 300 represent examples of decoding devices, specifically, examples of video encoders and video decoders, respectively. In some examples, source device 102 and destination device 116 may operate in a substantially symmetrical manner, such that each of source device 102 and destination device 116 includes video encoding and decoding components. Therefore, system 100 can support one-way or two-way video transmission between source device 102 and destination device 116, for example, for video streaming, video playback, video broadcasting, or video telephony.

[0093] Typically, video source 104 represents a source of video data (i.e., raw, unencoded video data) and provides a continuous series of pictures (also referred to as “frames”) of video data to video encoder 200, which encodes the data of the pictures. Video source 104 of source device 102 may include video capture devices such as cameras, video archives containing previously captured raw video, and / or video feed interfaces receiving video from video content providers. As a further alternative, video source 104 may generate computer graphics-based data as source video, or a combination of live video, archived video, and computer-generated video. In each case, video encoder 200 encodes the captured, pre-captured, or computer-generated video data. Video encoder 200 may rearrange the pictures from the receiving order (sometimes referred to as “display order”) into a decoding order for decoding. Video encoder 200 may generate a bitstream comprising the encoded video data. Then, the source device 102 can output encoded video data to the computer-readable medium 110 via the output interface 108 for reception and / or acquisition, for example, by the input interface 122 of the destination device 116.

[0094] The memory 106 of source device 102 and the memory 120 of destination device 116 represent general-purpose memory. In some examples, memories 106 and 120 may store raw video data, such as raw video from video source 104 and raw, undecoded video data from video decoder 300. Additionally or alternatively, memories 106 and 120 may store software instructions executable by, for example, video encoder 200 and video decoder 300, respectively. Although memories 106 and 120 are shown as separate from video encoder 200 and video decoder 300 in this example, it should be understood that video encoder 200 and video decoder 300 may also include internal memory for functionally similar or equivalent purposes. Furthermore, memories 106 and 120 may store, for example, unencoded video data output from video encoder 200 and input to video decoder 300. In some examples, portions of memories 106 and 120 may be allocated as one or more video buffers, for example, to store raw, undecoded, and / or unencoded video data.

[0095] Computer-readable medium 110 can represent any type of medium or device capable of transmitting encoded video data from source device 102 to destination device 116. In one example, computer-readable medium 110 represents a communication medium that enables source device 102 to transmit encoded video data directly to destination device 116 in real time, for example, via a radio frequency network or a computer-based network. According to a communication standard such as a wireless communication protocol, output interface 108 can modulate the transmitted signal including the encoded video data, and input interface 122 can demodulate the received transmitted signal. The communication medium can include any wireless or wired communication medium, such as radio frequency (RF) spectrum or one or more physical transmission lines. The communication medium can form part of a packet-based network, such as a local area network, a wide area network, or a global network such as the Internet. The communication medium can include a router, switch, base station, or any other equipment that can help facilitate communication from source device 102 to destination device 116.

[0096] In some examples, source device 102 can output encoded data to storage device 112 from output interface 108. Similarly, destination device 116 can access encoded data from storage device 112 via input interface 122. Storage device 112 may include any of a variety of distributed or locally accessed data storage media, such as hard disk drives, Blu-ray discs, DVDs, CD-ROMs, flash memory, volatile or non-volatile memory, or any other suitable digital storage medium for storing encoded video data.

[0097] In some examples, source device 102 may output encoded video data to file server 114 or another intermediate storage device that may store the encoded video data generated by source device 102. Destination device 116 may access the stored video data from file server 114 via streaming or downloading.

[0098] File server 114 can be any type of server device capable of storing encoded video data and sending the encoded video data to destination device 116. File server 114 can represent a web server (e.g., for a website), a server configured to provide file transfer protocol services (such as File Transfer Protocol (FTP) or One-Way File Transfer (FLUTE) protocol), a content delivery network (CDN) device, a Hypertext Transfer Protocol (HTTP) server, a Multimedia Broadcast Multicast Service (MBMS) or Enhanced MBMS (eMBMS) server, and / or a Network Attached Storage (NAS) device. File server 114 may additionally or alternatively implement one or more HTTP streaming protocols, such as HTTP-based Dynamic Adaptive Streaming (DASH), HTTP Live Streaming (HLS), Real-Time Streaming Protocol (RTSP), HTTP Dynamic Streaming, etc.

[0099] Destination device 116 can access encoded video data from file server 114 via any standard data connection, including an Internet connection. This connection may include a wireless channel (e.g., a Wi-Fi connection), a wired connection (e.g., a digital subscriber line (DSL), a cable modem, etc.), or a combination of both suitable for accessing encoded video data stored on file server 114. Input interface 122 can be configured to operate according to any one or more of the various protocols discussed above for obtaining or receiving media data from file server 114, or other such protocols for obtaining media data.

[0100] Output interface 108 and input interface 122 can represent a wireless transmitter / receiver, a modem, a wired networking component (e.g., an Ethernet card), a wireless communication component operating according to any of the various IEEE 802.11 standards, or other physical components. In examples where output interface 108 and input interface 122 include wireless components, output interface 108 and input interface 122 can be configured to transmit data, such as encoded video data, according to cellular communication standards such as 4G, 4G-LTE (Long Term Evolution), Advanced LTE, 5G, etc. In some examples where output interface 108 includes a wireless transmitter, output interface 108 and input interface 122 can be configured to comply with specifications such as IEEE 802.11, IEEE 802.15 (e.g., ZigBee).TM Bluetooth TM Other wireless standards, such as the standard, are used to transmit data, such as encoded video data. In some examples, source device 102 and / or destination device 116 may include corresponding system-on-chip (SoC) devices. For example, source device 102 may include an SoC device performing functions belonging to video encoder 200 and / or output interface 108, and destination device 116 may include an SoC device performing functions belonging to video decoder 300 and / or input interface 122.

[0101] The technology disclosed herein can be applied to video decoding to support any of a variety of multimedia applications, such as over-the-air television broadcasting, cable television transmission, satellite television transmission, Internet streaming video transmission (such as HTTP-based Dynamic Adaptive Streaming (DASH)), digital video encoded onto a data storage medium, decoding digital video stored on a data storage medium, or other applications.

[0102] The input interface 122 of the destination device 116 receives an encoded video bitstream from a computer-readable medium 110 (e.g., a communication medium, storage device 112, file server 114, etc.). The encoded video bitstream may include signaling information defined by the video encoder 200, which is also used by the video decoder 300, such as syntax elements having values ​​describing the characteristics and / or processing of video blocks or other decoded units (e.g., slices, pictures, picture groups, sequences, etc.). The display device 118 displays a decoded image of the decoded video data to the user. The display device 118 may represent any of a variety of display devices, such as a liquid crystal display (LCD), a plasma display, an organic light-emitting diode (OLED) display, or another type of display device.

[0103] although Figure 1 Not shown, but in some examples, the video encoder 200 and video decoder 300 may each be integrated with the audio encoder and / or audio decoder, and may include appropriate MUX-DEMUX units or other hardware and / or software to handle multiplexed streams including both audio and video in a common data stream. Where applicable, the MUX-DEMUX unit may conform to the ITU H.223 multiplexer protocol or other protocols such as User Datagram Protocol (UDP).

[0104] The video encoder 200 and / or video decoder 300 can each be implemented as any of a variety of suitable encoder and / or decoder circuits, such as one or more microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), discrete logic devices, software, hardware, firmware, or any combination thereof. When these technologies are not fully implemented in software, the device may store instructions for software in a suitable non-transitory computer-readable medium and use one or more processors to execute the instructions in the hardware to perform the technologies of this disclosure. Each of the video encoder 200 and video decoder 300 may be included in one or more encoders or decoders, either of which may be integrated as part of a combined encoder / decoder (CODEC) in the respective device. Devices including the video encoder 200 and / or video decoder 300 may include integrated circuits, microprocessors, and / or wireless communication devices such as cellular phones.

[0105] The video encoder 200 and video decoder 300 may operate according to video decoding standards such as ITU-TH.265, also known as High Efficiency Video Decoding (HEVC) or its extensions, such as Multi-View and / or Scalable Video Decoding Extensions. Alternatively, the video encoder 200 and video decoder 300 may operate according to other proprietary or industry standards such as ITU-TH.266, also known as Multi-Functional Video Decoding (VVC). A draft of the VVC standard is described in “Multi-Functional Video Decoding (Draft 10)” (hereinafter referred to as “VVC Draft 10”) published by Bross et al. at the 20th teleconference (JVET-T2001-v2) of the Joint Video Experts Group (JVET) of ITU-T SG 16WP 3 and ISO / IEC JTC1 / SC 29 / WG 11, held from 7 to 16 October 2020. However, the technology disclosed herein is not limited to any particular decoding standard.

[0106] Typically, video encoder 200 and video decoder 300 can perform block-based decoding of images. The term "block" generally refers to a structure that includes data to be processed (e.g., encoded, decoded, or otherwise used in the encoding and / or decoding process). For example, a block may include a two-dimensional matrix of samples of luminance and / or chrominance data. Typically, video encoder 200 and video decoder 300 can decode video data represented in YUV (e.g., Y, Cb, Cr) format. That is, video encoder 200 and video decoder 300 can decode both luminance and chrominance components, where the chrominance components may include both red and blue chrominance components, rather than decoding red, green, and blue (RGB) data of samples of the image. In some examples, video encoder 200 converts received RGB-formatted data to a YUV representation before encoding, and video decoder 300 converts the YUV representation to RGB format. Alternatively, preprocessing and post-processing units (not shown) can perform these conversions.

[0107] This disclosure generally relates to the decoding (e.g., encoding and decoding) of images, which includes processes of encoding or decoding data of the images. Similarly, this disclosure may relate to the decoding of blocks of images, which includes processes of encoding or decoding data of blocks (e.g., prediction and / or residual decoding). Encoded video bitstreams typically include a series of values ​​representing decoding decisions (e.g., decoding modes) and syntax elements that divide images into blocks. Therefore, references to decoding images or blocks should generally be understood as the decoded values ​​of the syntax elements that form images or blocks.

[0108] HEVC defines various blocks, including decoding units (CUs), prediction units (PUs), and transform units (TUs). According to HEVC, a video decoder (such as a video encoder 200) divides the decoding tree unit (CTU) into CUs according to a quadtree structure. That is, the video decoder divides the CTU and CU into four equal, non-overlapping squares, and each node of the quadtree has zero or four child nodes. Nodes without child nodes can be called "leaf nodes," and the CU of this leaf node can include one or more PUs and / or one or more TUs. The video decoder can also partition PUs and TUs. For example, in HEVC, a residual quadtree (RQT) represents the partitioning of TUs. In HEVC, PUs represent inter-frame prediction data, while TUs represent residual data. CUs with intra-frame prediction include intra-frame prediction information, such as intra-frame mode indication.

[0109] As another example, video encoder 200 and video decoder 300 can be configured to operate according to VVC. According to VVC, the video decoder (such as video encoder 200) partitions the image into multiple decoding tree units (CTUs). Video encoder 200 can partition the CTUs according to a tree structure (such as a quadtree-binary tree (QTBT) structure or a multi-type tree (MTT) structure). The QTBT structure eliminates the concept of multiple partitioning types, such as the separation between CUs, PUs, and TUs in HEVC. The QTBT structure consists of two levels: a first level partitioned according to a quadtree and a second level partitioned according to a binary tree. The root node of the QTBT structure corresponds to a CTU. The leaf nodes of the binary tree correspond to decoding units (CUs).

[0110] In the MTT partitioning structure, blocks can be partitioned using quadtree (QT), binary tree (BT), and one or more types of triple tree (TT) partitions (also known as ternary tree (TT) partitions). A triple tree or ternary tree partition is a partition that divides a block into three sub-blocks. In some examples, a triple tree or ternary tree partition divides a block into three sub-blocks without partitioning the original block by a center. The partitioning type in an MTT (e.g., QT, BT, and TT) can be symmetric or asymmetric.

[0111] In some examples, the video encoder 200 and the video decoder 300 may use a single QTBT or MTT structure to represent each of the luma and chroma components, while in other examples, the video encoder 200 and the video decoder 300 may use two or more QTBT or MTT structures, such as one QTBT / MTT structure for the luma component and another QTBT / MTT structure for the two chroma components (or two QTBT / MTT structures for the respective chroma components).

[0112] The video encoder 200 and video decoder 300 can be configured to use per-HEVC quadtree partitioning, QTBT partitioning, MTT partitioning, or other partitioning structures. For illustrative purposes, the description of the technology in this disclosure is presented with respect to QTBT partitioning. However, it should be understood that the technology in this disclosure can also be applied to video decoders configured to use quadtree partitioning or other types of partitioning.

[0113] In some examples, a CTU includes a decoded tree block (CTB) of luminance samples, two corresponding CTBs of chrominance samples of an image with three sample arrays, or a CTB of samples of a monochrome image or an image decoded using three separate color planes and a syntax structure for decoding the samples. A CTB can be an N×N block of samples with a certain N value, such that partitioning is to divide the components into CTBs. A component is an array or a single sample from one of the three arrays (luminance and two chrominance) that make up an image in a 4:2:0, 4:2:2, or 4:4:4 color format, or an array or a single sample from an array or array that makes up an image in monochrome format. In some examples, a decoded block is an M×N block of samples with certain M and N values, such that partitioning is to divide the CTB into decoded blocks.

[0114] Blocks (e.g., CTUs or CUs) can be grouped in various ways within an image. As an example, a brick can refer to a rectangular area of ​​a row of CTUs within a specific tile in an image. A brick can be a rectangular area of ​​CTUs within a specific tile column and a specific tile row in an image. A tile column refers to a rectangular area of ​​CTUs with a height equal to the image height and a width specified by a syntax element (e.g., a syntax element in the image parameter set). A tile row refers to a rectangular area of ​​CTUs with a height specified by a syntax element (e.g., a syntax element in the image parameter set) and a width equal to the image width.

[0115] In some examples, a tile can be divided into multiple bricks, each brick containing one or more CTU rows within the tile. A tile that is not divided into multiple bricks can also be called a brick. However, a brick that is a proper subset of a tile cannot be called a tile.

[0116] The bricks in an image can also be arranged as slices. A slice can be an integer number of bricks in an image that can be exclusively contained within a single Network Abstraction Layer (NAL) unit. In some examples, a slice consists of a continuous sequence of several complete tiles or a single complete tile.

[0117] This disclosure uses “N×N” and “N multiplied by N” interchangeably to refer to the sample dimensions of a block (such as a CU or other video block) in the vertical and horizontal dimensions, for example, 16×16 samples or 16 by 16 samples. Typically, a 16×16 CU will have 16 samples in the vertical direction (y = 16) and 16 samples in the horizontal direction (x = 16). Similarly, an N×N CU typically has N samples in the vertical direction and N samples in the horizontal direction, where N represents a non-negative integer value. Samples in a CU can be arranged in rows and columns. Furthermore, a CU does not necessarily need to have the same number of samples in the horizontal direction as in the vertical direction. For example, a CU can include N×M samples, where M is not necessarily equal to N.

[0118] The video encoder 200 encodes video data of the CU (Complex Unit), which represents prediction and / or residual information, as well as other information. Prediction information indicates how the CU will be predicted to form a prediction block of the CU. Residual information typically represents the sample-by-sample difference between a sample of the CU before encoding and the prediction block.

[0119] To predict the Cubic Frame (CU), the video encoder 200 typically forms a prediction block of the CU through inter-frame prediction or intra-frame prediction. Inter-frame prediction generally refers to predicting the CU from data of a previously decoded image, while intra-frame prediction generally refers to predicting the CU from previously decoded data of the same image. To perform inter-frame prediction, the video encoder 200 can use one or more motion vectors to generate prediction blocks. The video encoder 200 can typically perform a motion search to identify reference blocks that closely match the CU, for example, in terms of the differences between the CU and a reference block. The video encoder 200 can use sum of absolute differences (SAD), sum of squared differences (SSD), mean absolute difference (MAD), mean squared difference (MSD), or other such difference calculations to compute difference metrics to determine whether a reference block closely matches the current CU. In some examples, the video encoder 200 can use unidirectional or bidirectional prediction to predict the current CU.

[0120] Some examples of VVC also provide an affine motion compensation mode, which can be considered an inter-frame prediction mode. In affine motion compensation mode, the video encoder 200 can determine two or more motion vectors representing non-translational motion (such as zooming in or out, rotation, perspective motion, or other irregular motion types).

[0121] To perform intra-frame prediction, the video encoder 200 can select an intra-frame prediction mode to generate prediction blocks. Some examples of VVC provide sixty-seven intra-frame prediction modes, including various orientation modes, as well as planar and DC modes. Typically, the video encoder 200 selects an intra-frame prediction mode that describes samples adjacent to the current block (e.g., a block of a CU), from which samples of the current block are predicted. Assuming the video encoder 200 decodes the CTU and CU in raster scan order (from left to right, from top to bottom), such samples are typically located above, to the upper left, or to the left of the current block in the same image as the current block.

[0122] The video encoder 200 encodes data representing the prediction mode of the current block. For example, for inter-frame prediction modes, the video encoder 200 can encode data indicating which of the various available inter-frame prediction modes is being used, and the motion information of the corresponding mode. For example, for unidirectional or bidirectional inter-frame prediction, the video encoder 200 can use Advanced Motion Vector Prediction (AMVP) or merging modes to encode motion vectors. The video encoder 200 can use similar modes to encode motion vectors for affine motion compensation modes.

[0123] Following prediction, such as intra-frame or inter-frame prediction of a block, the video encoder 200 can compute residual data for the block. The residual data (such as residual blocks) represents the sample-wise difference between the predicted blocks of the block and the block itself, formed using the corresponding prediction mode. The video encoder 200 can apply one or more transforms to the residual blocks to produce transformed data in the transform domain rather than the sample domain. For example, the video encoder 200 can apply Discrete Cosine Transform (DCT), integer transform, wavelet transform, or conceptually similar transforms to the residual video data. Furthermore, the video encoder 200 can apply secondary transforms after the first transform, such as Mode-dependent Inseparable Secondary Transform (MDNSST), Signal-dependent Transform, Karhunen-Loeve Transform (KLT), etc. The video encoder 200 produces transform coefficients after applying one or more transforms.

[0124] As noted above, after any transform that produces the transform coefficients, the video encoder 200 can perform quantization of the transform coefficients. Quantization generally refers to a process in which transform coefficients are quantized to minimize the amount of data used to represent them, thereby providing further compression. By performing the quantization process, the video encoder 200 can reduce the bit depth associated with some or all of the transform coefficients. For example, the video encoder 200 can round an n-bit value down to an m-bit value during quantization, where n is greater than m. In some examples, to perform quantization, the video encoder 200 can perform a bitwise right shift of the values ​​to be quantized.

[0125] After quantization, the video encoder 200 can scan the transform coefficients to generate a one-dimensional vector from a two-dimensional matrix including the quantized transform coefficients. The scan can be designed to place higher-energy (and therefore lower-frequency) transform coefficients before the vector and lower-energy (and therefore higher-frequency) transform coefficients after the vector. In some examples, the video encoder 200 can utilize a predefined scan order to scan the quantized transform coefficients to produce a serialized vector, and then entropy-encode the quantized transform coefficients of the vector. In other examples, the video encoder 200 can perform an adaptive scan. After scanning the quantized transform coefficients to form a one-dimensional vector, the video encoder 200 can entropy-encode the one-dimensional vector, for example, according to context-adaptive binary arithmetic decoding (CABAC). The video encoder 200 can also entropy-encode the values ​​of syntax elements describing metadata associated with the encoded video data for use by the video decoder 300 when decoding the video data.

[0126] To perform CABAC, the video encoder 200 can assign context within a context model to the symbols to be transmitted. The context may involve, for example, whether the symbol's neighboring values ​​are zero. Probability determination can be based on the context assigned to the symbols.

[0127] The video encoder 200 can, for example, provide the video decoder 300 with further syntax data in the image header, block header, slice header, or other syntax data (such as sequence parameter sets (SPS), picture parameter sets (PPS), or video parameter sets (VPS)). This syntax data can be block-based, image-based, or sequence-based. Similarly, the video decoder 300 can decode this syntax data to determine how to decode the corresponding video data.

[0128] In this way, the video encoder 200 can generate a bitstream that includes encoded video data, such as syntax elements describing the division of images into blocks (e.g., CUs) and prediction and / or residual information for the blocks. Finally, the video decoder 300 can receive the bitstream and decode the encoded video data.

[0129] Typically, the video decoder 300 performs the inverse of the process performed by the video encoder 200 to decode the encoded video data of the bitstream. For example, the video decoder 300 can use CABAC to decode the values ​​of the syntax elements of the bitstream in a manner substantially similar to but inverse of the CABAC encoding process of the video encoder 200. Syntax elements can define partitioning information for dividing a picture into CTUs and further partitioning each CTU according to a corresponding partitioning structure such as a QTBT structure to define the CUs of the CTU. Syntax elements can further define prediction and residual information for blocks (e.g., CUs) of the video data.

[0130] The residual information can be represented, for example, by quantized transform coefficients. The video decoder 300 can inversely quantize and inversely transform the quantized transform coefficients of the block to reconstruct the residual block of the block. The video decoder 300 uses the signal-informed prediction mode (intra-frame prediction or inter-frame prediction) and associated prediction information (e.g., motion information from inter-frame prediction) to form a predicted block of the block. The video decoder 300 can then combine the predicted block with the residual block (on a sample-by-sample basis) to reconstruct the original block. The video decoder 300 can perform additional processing, such as performing a deblocking process to reduce visual artifacts along the block boundaries.

[0131] According to one or more techniques disclosed herein, a video decoder (e.g., a video encoder and / or video decoder) can insert DIMD-derived patterns into an MPM list. Thus, the video decoder can decode blocks using DIMD-derived patterns from an intra-frame predicted MPM list.

[0132] This disclosure may generally relate to "signaling" certain information, such as syntax elements. The term "signaling" can generally refer to communication of syntax elements and / or other data used for decoding encoded video data. That is, video encoder 200 may signal the value of syntax elements in the bitstream. Typically, signaling refers to generating a value in the bitstream. As noted above, source device 102 may deliver the bitstream to destination device 116 substantially in real time or non-real time (such as when syntax elements are stored in storage device 112 for later retrieval by destination device 116).

[0133] According to one or more techniques disclosed herein, encoder 200 and / or decoder 300 can insert one or more derived DIMD modes into an MPM list. For example, encoder 200 and / or decoder 300 can perform... Figure 10 The technology.

[0134] Figure 2A and Figure 2BThis is a conceptual diagram illustrating an example Quadtree Binary Tree (QTBT) structure 130 and its corresponding Decoding Tree Unit (CTU) 132. Solid lines represent quadtree splits, and dashed lines indicate binary tree splits. In each split node (i.e., a non-leaf node) of the binary tree, a flag is signaled to indicate which split type (i.e., horizontal or vertical) is used, where in this example, 0 indicates a horizontal split and 1 indicates a vertical split. For quadtree splits, there is no need to indicate the split type because the quadtree node splits the block horizontally and vertically into four sub-blocks of equal size. Accordingly, the video encoder 200 can encode and the video decoder 300 can decode the syntax elements (such as splitting information) of the region tree level (i.e., solid lines) and the syntax elements (e.g., splitting information) of the prediction tree level (i.e., dashed lines) of the QTBT structure 130. The video encoder 200 can encode and the video decoder 300 can decode video data of the CU, such as prediction and transform data, represented by the terminal leaf nodes of the QTBT structure 130.

[0135] generally, Figure 2B The CTU 132 can be associated with parameters that define the size of the blocks corresponding to the nodes at the first and second levels of the QTBT structure 130. These parameters can include the CTU size (representing the size of the CTU 132 in the sample), the minimum quadtree size (MinQTSize, representing the minimum allowed size of a quadtree leaf node), the maximum binary tree size (MaxBTSize, representing the maximum allowed size of a binary tree root node), the maximum binary tree depth (MaxBTDepth, representing the maximum allowed depth of a binary tree), and the minimum binary tree size (MinBTSize, representing the minimum allowed size of a binary tree leaf node).

[0136] The root node of a QTBT structure corresponding to a CTU can have four child nodes at the first level of the QTBT structure, each child node being partitioned according to a quadtree partition. That is, the nodes at the first level are either leaf nodes (without child nodes) or have four child nodes. An example of QTBT structure 130 represents such nodes as including a parent node and child nodes with solid-line branches. If the nodes at the first level are not larger than the maximum allowed binary tree root node size (MaxBTSize), these nodes can be further partitioned by the corresponding binary tree. The binary tree partitioning of a node can be iterated until the resulting partitioned nodes reach the minimum allowed binary tree leaf node size (MinBTSize) or the maximum allowed binary tree depth (MaxBTDepth). An example of QTBT structure 130 represents such nodes as having dashed-line branches. The binary tree leaf nodes are called decoding units (CUs), which are used for prediction (e.g., intra-image prediction or inter-image prediction) and transformation without any further partitioning. As discussed above, CUs can also be referred to as “video blocks” or “blocks”.

[0137] In one example of a QTBT partitioning structure, the CTU size is set to 128×128 (luminance samples and two corresponding 64×64 chrominance samples), MinQTSize is set to 16×16, MaxBTSize is set to 64×64, MinBTSize (for both width and height) is set to 4, and MaxBTDepth is set to 4. First, a quadtree partition is applied to the CTU to generate quadtree leaf nodes. Quadtree leaf nodes can have sizes ranging from 16×16 (i.e., MinQTSize) to 128×128 (i.e., the CTU size). If a quadtree leaf node is 128×128, the leaf quadtree node will not be further partitioned by the binary tree because its size exceeds MaxBTSize (i.e., 64×64 in this example). Otherwise, the quadtree leaf node will be further partitioned by the binary tree. Therefore, the quadtree leaf node is also the root node of the binary tree, and its binary tree depth is 0. When the depth of the binary tree reaches MaxBTDepth (4 in this example), any further splits are not permitted. A binary tree node with a width equal to MinBTSize (4 in this example) means that for that binary tree node, any further vertical splits (i.e., width splits) are not permitted. Similarly, a binary tree node with a height equal to MinBTSize means that for that binary tree node, any further horizontal splits (i.e., height splits) are not permitted. As noted above, the leaf nodes of the binary tree are called CUs and are further processed based on predictions and transformations without further splits.

[0138] Figure 3This is a block diagram illustrating an example video encoder 200 that can perform the techniques of this disclosure. Figure 3 This disclosure is provided for illustrative purposes and should not be construed as limiting the techniques broadly illustrated and described herein. For illustrative purposes, this disclosure describes a video encoder 200 based on VVC (ITU-T H.266, under development) and HEVC (ITU-T H.265) technologies. However, the techniques of this disclosure can be implemented by video encoding devices configured for other video decoding standards.

[0139] exist Figure 3 In the example, the video encoder 200 includes a video data memory 230, a mode selection unit 202, a residual generation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transform processing unit 212, a reconstruction unit 214, a filtering unit 216, a decoded image buffer (DPB) 218, and an entropy encoding unit 220. Any or all of the video data memory 230, mode selection unit 202, residual generation unit 204, transform processing unit 206, quantization unit 208, inverse quantization unit 210, inverse transform processing unit 212, reconstruction unit 214, filtering unit 216, DPB 218, and entropy encoding unit 220 can be implemented as one or more processors or as processing circuitry. For example, the units of the video encoder 200 can be implemented as one or more circuit or logic elements, as part of hardware circuitry or as part of a processor, ASIC, or FPGA. Furthermore, the video encoder 200 may include additional or alternative processors or processing circuitry to perform these and other functions.

[0140] The video data storage device 230 can store video data encoded by components of the video encoder 200. The video encoder 200 can retrieve data from, for example, a video source 104 (…). Figure 1 The video encoder 200 receives video data stored in video data memory 230. DPB 218 can act as a reference picture memory, storing reference video data for use by the video encoder 200 when predicting subsequent video data. Video data memory 230 and DPB 218 can be formed from any of a variety of memory devices, such as dynamic random access memory (DRAM), including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. Video data memory 230 and DPB 218 can be provided by the same memory device or separate memory devices. In various examples, video data memory 230 can be on-chip with other components of the video encoder 200 as illustrated, or off-chip relative to those components.

[0141] In this disclosure, references to video data memory 230 should not be construed as limited to memory within video encoder 200 unless specifically described therein, or to memory external to video encoder 200 unless specifically described therein. Rather, references to video data memory 230 should be understood as a reference memory storing video data (e.g., video data of the current block to be encoded) received by video encoder 200 for encoding. Figure 1 The memory 106 can also provide temporary storage for the outputs from the various units of the video encoder 200.

[0142] Illustration Figure 3 The various units help to understand the operations performed by the video encoder 200. These units can be implemented as fixed-function circuits, programmable circuits, or a combination thereof. Fixed-function circuits refer to circuits that provide specific functionality and are pre-configured for the operations that can be performed. Programmable circuits refer to circuits that can be programmed to perform various tasks and provide flexible functionality in the operations that can be performed. For example, a programmable circuit can execute software or firmware that causes the programmable circuit to operate in a manner defined by the instructions of the software or firmware. Fixed-function circuits can execute software instructions (e.g., to receive or output parameters), but the type of operation performed by a fixed-function circuit is generally immutable. In some examples, one or more of these units can be dissimilar circuit blocks (fixed-function or programmable), and in some examples, one or more of these units can be integrated circuits.

[0143] The video encoder 200 may include an arithmetic logic unit (ALU), an essential function unit (EFU), digital circuitry, analog circuitry, and / or a programmable core, all formed by programmable circuitry. In an example where the operation of the video encoder 200 is performed using software executed by programmable circuitry, memory 106 ( Figure 1 The video encoder 200 may store instructions (e.g., object code) of the software received and executed by the video encoder 200, or another memory (not shown) within the video encoder 200 may store such instructions.

[0144] The video data storage unit 230 is configured to store received video data. The video encoder 200 can retrieve images of the video data from the video data storage unit 230 and provide the video data to the residual generation unit 204 and the mode selection unit 202. The video data in the video data storage unit 230 can be the raw video data to be encoded.

[0145] The mode selection unit 202 includes a motion estimation unit 222, a motion compensation unit 224, and an intra-frame prediction unit 226. The mode selection unit 202 may include additional functional units to perform video prediction based on other prediction modes. As an example, the mode selection unit 202 may include a palette unit, an intra-block copy unit (which may be part of the motion estimation unit 222 and / or the motion compensation unit 224), an affine unit, a linear model (LM) unit, etc.

[0146] The mode selection unit 202 typically coordinates multiple encoding processes to test combinations of encoding parameters and the resulting rate-distortion (RDD) values. Encoding parameters may include dividing the CTU into CUs, the prediction modes of the CUs, the transformation type of the CU residual data, and the quantization parameters of the CU residual data. The mode selection unit 202 can ultimately select a combination of encoding parameters that yields a better RTD value than other tested combinations.

[0147] The video encoder 200 can divide an image obtained from the video data storage 230 into a series of CTUs and encapsulate one or more CTUs within a slice. The mode selection unit 202 can divide the image into CTUs according to a tree structure (such as a QTBT structure or the quadtree structure of HEVC described above). As mentioned above, the video encoder 200 can form one or more CUs from the CTUs divided according to the tree structure. This CU can also generally be referred to as a "video block" or "block".

[0148] Typically, mode selection unit 202 also controls its components (e.g., motion estimation unit 222, motion compensation unit 224, and intra-frame prediction unit 226) to generate a predicted block for the current block (e.g., the current CU, or, in HEVC, the overlapping portion of PU and TU). For inter-frame prediction of the current block, motion estimation unit 222 may perform a motion search to identify one or more closely matching reference blocks in one or more reference images (e.g., one or more previously decoded images stored in DPB 218). Specifically, motion estimation unit 222 may calculate values ​​representing how similar a potential reference block is to the current block, for example, based on sum of absolute differences (SAD), sum of squared differences (SSD), mean absolute difference (MAD), mean squared difference (MSD), etc. Motion estimation unit 222 may typically perform these calculations using the sample-by-sample difference between the current block and the reference block being considered. Motion estimation unit 222 may identify the reference block with the lowest value obtained from these calculations, thereby indicating the reference block that most closely matches the current block.

[0149] Motion estimation unit 222 can generate one or more motion vectors (MVs) that define the position of a reference block in a reference image relative to the position of a current block in the current image. Motion estimation unit 222 can then provide these motion vectors to motion compensation unit 224. For example, for unidirectional inter-frame prediction, motion estimation unit 222 can provide a single motion vector, while for bidirectional inter-frame prediction, it can provide two motion vectors. Motion compensation unit 224 can then use the motion vectors to generate prediction blocks. For example, motion compensation unit 224 can use the motion vectors to obtain data for the reference blocks. As another example, if the motion vectors have fractional-sample precision, motion compensation unit 224 can interpolate the values ​​of the prediction blocks according to one or more interpolation filters. Furthermore, for bidirectional inter-frame prediction, motion compensation unit 224 can obtain data for two reference blocks identified by corresponding motion vectors and combine the obtained data, for example, by per-sample averaging or weighted averaging.

[0150] As another example, for intra-prediction or intra-prediction decoding, intra-prediction unit 226 can generate a prediction block from samples neighboring the current block. For example, in directional mode, intra-prediction unit 226 can typically mathematically combine the values ​​of neighboring samples and fill these calculated values ​​in a defined direction on the current block to generate a prediction block. As another example, in DC mode, intra-prediction unit 226 can calculate the average of the neighboring samples of the current block and generate a prediction block to include the resulting average for each sample of the prediction block.

[0151] Mode selection unit 202 provides a prediction block to residual generation unit 204. Residual generation unit 204 receives the raw, uncoded version of the current block from video data memory 230 and the prediction block from mode selection unit 202. Residual generation unit 204 calculates the sample-by-sample difference between the current block and the prediction block. The resulting sample-by-sample difference defines the residual block of the current block. In some examples, residual generation unit 204 can also determine the differences between sample values ​​in the residual block to generate the residual block using residual differential pulse decode-modulation (RDPCM). In some examples, residual generation unit 204 can be formed using one or more subtractor circuits that perform binary subtraction.

[0152] In the example where mode selection unit 202 divides a CU into PUs, each PU can be associated with a luma prediction unit and a corresponding chroma prediction unit. Video encoder 200 and video decoder 300 can support PUs of various sizes. As indicated above, the size of a CU can refer to the size of its luma decoding block, and the size of a PU can refer to the size of the luma prediction unit of that PU. Assuming a particular CU has a size of 2N×2N, then video encoder 200 can support PU sizes of 2N×2N or N×N for intra-frame prediction and symmetrical PU sizes of 2N×2N, 2N×N, N×2N, N×N, or similar sizes for inter-frame prediction. Video encoder 200 and video decoder 300 can also support asymmetric partitioning of PU sizes of 2N×nU, 2N×nD, nL×2N, and nR×2N for inter-frame prediction.

[0153] In the example where mode selection unit 202 does not further divide the CU into PUs, each CU can be associated with a luma decoding block and a corresponding chroma decoding block. As mentioned above, the size of the CU can refer to the size of the luma decoding block of the CU. The video encoder 200 and the video decoder 300 can support CU sizes of 2N×2N, 2N×N, or N×2N.

[0154] For other video decoding techniques, such as intra-block copy mode decoding, affine mode decoding, and linear model (LM) mode decoding, as examples, mode selection unit 202 generates a prediction block of the current block being encoded via a corresponding unit associated with the decoding technique. In some examples, such as palette mode decoding, mode selection unit 202 may not generate a prediction block, but instead generate syntax elements indicating how the block should be reconstructed based on a selected palette. In such modes, mode selection unit 202 may provide these syntax elements to entropy coding unit 220 for encoding.

[0155] As described above, the residual generation unit 204 receives video data of the current block and the corresponding prediction block. The residual generation unit 204 then generates a residual block for the current block. To generate the residual block, the residual generation unit 204 calculates the sample-by-sample difference between the prediction block and the current block.

[0156] Transform processing unit 206 applies one or more transformations to the residual block to generate a block of transform coefficients (referred to herein as a "transform coefficient block"). Transform processing unit 206 may apply various transformations to the residual block to form the transform coefficient block. For example, transform processing unit 206 may apply discrete cosine transform (DCT), direction transformation, Karhunen-Loeve transform (KLT), or conceptually similar transformations to the residual block. In some examples, transform processing unit 206 may perform multiple transformations on the residual block, such as primary and secondary transformations, such as rotation transformations. In some examples, transform processing unit 206 does not apply any transformations to the residual block.

[0157] Quantization unit 208 can quantize the transform coefficients in the transform coefficient block to produce a quantized transform coefficient block. Quantization unit 208 can quantize the transform coefficients of the transform coefficient block based on the quantization parameter (QP) value associated with the current block. Video encoder 200 (e.g., via mode selection unit 202) can adjust the degree of quantization applied to the transform coefficient block associated with the current block by adjusting the QP value associated with the CU. Quantization can introduce information loss, and therefore, the quantized transform coefficients can have lower precision than the original transform coefficients generated by transform processing unit 206.

[0158] The inverse quantization unit 210 and the inverse transform processing unit 212 can apply inverse quantization and inverse transform to the quantized transform coefficient block, respectively, to reconstruct the residual block from the transform coefficient block. The reconstruction unit 214 can generate a reconstructed block corresponding to the current block based on the reconstructed residual block and the prediction block generated by the mode selection unit 202 (although potentially with some degree of distortion). For example, the reconstruction unit 214 can add samples of the reconstructed residual block to corresponding samples of the prediction block generated by the mode selection unit 202 to generate the reconstructed block.

[0159] Filtering unit 216 can perform one or more filtering operations on the reconstructed block. For example, filtering unit 216 can perform deblocking to reduce block artifacts along the edges of the CU. In some examples, the operation of filtering unit 216 can be skipped.

[0160] The video encoder 200 stores the reconstructed blocks in the DPB 218. For example, in an example where the filtering unit 216 is not operated, the reconstruction unit 214 can store the reconstructed blocks in the DPB 218. In an example where the filtering unit 216 is operated, the filtering unit 216 can store the filtered reconstructed blocks in the DPB 218. The motion estimation unit 222 and the motion compensation unit 224 can obtain a reference picture formed by the reconstructed (and potentially filtered) blocks from the DPB 218 to perform inter-frame prediction of blocks in subsequent encoded pictures. Furthermore, the intra-frame prediction unit 226 can use the reconstructed blocks in the DPB 218 of the current picture to perform intra-frame prediction of other blocks in the current picture.

[0161] Typically, entropy coding unit 220 can entropy code syntax elements received from other functional components of video encoder 200. For example, entropy coding unit 220 can entropy code quantized transform coefficient blocks from quantization unit 208. As another example, entropy coding unit 220 can entropy code predictive syntax elements (e.g., motion information for inter-frame prediction or intra-frame mode information for intra-frame prediction) from mode selection unit 202. Entropy coding unit 220 can perform one or more entropy coding operations on syntax elements, which is another example of video data, to generate entropy-coded data. For example, entropy coding unit 220 can perform context-adaptive variable-length decoding (CAVLC), CABAC, variable-to-variable (V2V) length decoding, syntax-based context-adaptive binary arithmetic decoding (SBAC), probability interval partitioning entropy (PIPE) decoding, exponential-Golomb coding, or another type of entropy coding operation on the data. In some examples, the entropy coding unit 220 can operate in a bypass mode in which syntax elements are not entropy encoded.

[0162] The video encoder 200 can output a bitstream containing entropy-encoded syntax elements required to reconstruct slices or blocks of images. Specifically, the entropy coding unit 220 can output a bitstream.

[0163] The above operations are described in terms of blocks. This description should be understood as operations applied to the luma decoding block and / or the chroma decoding block. As mentioned above, in some examples, the luma decoding block and the chroma decoding block are the luma and chroma components of the CU. In some examples, the luma decoding block and the chroma decoding block are the luma and chroma components of the PU.

[0164] In some examples, for the chroma decoding block, it is not necessary to repeat the operations performed for the luma decoding block. As an example, the operations for identifying the motion vector (MV) and reference image of the luma decoding block do not need to be repeated for identifying the MV and reference image of the chroma block. Instead, the MV of the luma decoding block can be scaled to determine the MV of the chroma block, and the reference image can be the same. As another example, the intra-frame prediction process can be the same for both the luma and chroma decoding blocks.

[0165] Video encoder 200 represents an example of a device configured to encode video data, comprising: a memory configured to store video data, and one or more processing units implemented in circuitry and configured to: derive a list of intra-modes for the current block of video data using reconstructed samples from neighboring blocks and decoder-side intra-mode derivation (DIMD); construct a most probable mode (MPM) list for the current block, the MPM list including at least one intra-mode from the derived list of intra-modes; and predict the current block using candidates selected from the constructed MPM list.

[0166] Figure 4 This is a block diagram illustrating an example video decoder 300 capable of performing the techniques of this disclosure. Figure 4 This disclosure is provided for illustrative purposes and is not limited to the techniques broadly illustrated and described herein. For illustrative purposes, this disclosure describes a video decoder 300 based on VVC (ITU-T H.266, under development) and HEVC (ITU-T H.265) technologies. However, the techniques of this disclosure can be implemented by video decoding devices configured for other video decoding standards.

[0167] exist Figure 4 In the example, the video decoder 300 includes a decoded picture buffer (CPB) memory 320, an entropy decoding unit 302, a prediction processing unit 304, an inverse quantization unit 306, an inverse transform processing unit 308, a reconstruction unit 310, a filtering unit 312, and a decoded picture buffer (DPB) 314. Any or all of the CPB memory 320, entropy decoding unit 302, prediction processing unit 304, inverse quantization unit 306, inverse transform processing unit 308, reconstruction unit 310, filtering unit 312, and DPB 314 can be implemented as one or more processors or as processing circuitry. For example, units of the video decoder 300 can be implemented as one or more circuit or logic elements as part of hardware circuitry, or as part of a processor, ASIC, or FPGA. Furthermore, the video decoder 300 may include additional or alternative processors or processing circuitry to perform these and other functions.

[0168] The prediction processing unit 304 includes a motion compensation unit 316 and an intra-frame prediction unit 318. The prediction processing unit 304 may include additional units to perform predictions based on other prediction modes. As an example, the prediction processing unit 304 may include a palette unit, an intra-block copy unit (which may form part of the motion compensation unit 316), an affine unit, a linear model (LM) unit, etc. In other examples, the video decoder 300 may include more, fewer, or different functional components.

[0169] CPB memory 320 can store video data, such as encoded video bitstreams, that will be decoded by components of video decoder 300. The video data stored in CPB memory 320 can be from, for example, computer-readable medium 110 (…). Figure 1 The CPB memory 320 may include a CPB that stores encoded video data (e.g., syntax elements) from the encoded video bitstream. Additionally, the CPB memory 320 may store video data other than the syntax elements of the decoded picture, such as temporary data representing the output from various units of the video decoder 300. The DPB 314 typically stores decoded pictures that the video decoder 300 may output and / or use as reference video data when decoding subsequent data or pictures from the encoded video bitstream. The CPB memory 320 and DPB 314 may be formed of any of a variety of memory devices, such as DRAM, including SDRAM, MRAM, RRAM, or other types of memory devices. The CPB memory 320 and DPB 314 may be provided by the same memory device or separate memory devices. In various examples, the CPB memory 320 may be on-chip with other components of the video decoder 300, or off-chip relative to those components.

[0170] Additionally or alternatively, in some examples, the video decoder 300 can be drawn from the memory 120 ( Figure 1 The decoded video data is obtained from the memory. That is, the memory 120 can store data as discussed above regarding the CPB memory 320. Similarly, when some or all of the functionality of the video decoder 300 is implemented in software that will be executed by the processing circuitry of the video decoder 300, the memory 120 can store instructions that will be executed by the video decoder 300.

[0171] The diagram shows Figure 4 The individual units shown aid in understanding the operations performed by the video decoder 300. These units can be implemented as fixed-function circuits, programmable circuits, or a combination thereof. Similar to... Figure 3Fixed-function circuits refer to circuits that provide specific functionality and are pre-configured for the operations they can perform. Programmable circuits refer to circuits that can be programmed to perform various tasks and provide flexible functionality in the operations they can perform. For example, a programmable circuit can execute software or firmware that causes the programmable circuit to operate in a manner defined by the instructions of the software or firmware. Fixed-function circuits can execute software instructions (e.g., to receive or output parameters), but the type of operation performed by a fixed-function circuit is typically immutable. In some examples, one or more of these units can be dissimilar circuit blocks (fixed-function or programmable), and in some examples, one or more of these units can be integrated circuits.

[0172] The video decoder 300 may include an ALU, EFU, digital circuitry, analog circuitry, and / or a programmable core formed by programmable circuitry. In an example where the operation of the video decoder 300 is performed by software executed on the programmable circuitry, on-chip or off-chip memory may store instructions (e.g., object code) of the software received and executed by the video decoder 300.

[0173] Entropy decoding unit 302 can receive encoded video data from CPB and perform entropy decoding on the video data to reproduce syntax elements. Prediction processing unit 304, inverse quantization unit 306, inverse transform processing unit 308, reconstruction unit 310, and filtering unit 312 can generate decoded video data based on syntax elements extracted from the bitstream.

[0174] Typically, the video decoder 300 reconstructs the image on a block-by-block basis. The video decoder 300 can perform the reconstruction operation on each block individually (where the block currently being reconstructed (i.e. decoded) can be referred to as the "current block").

[0175] Entropy decoding unit 302 can entropy decode the syntax elements defining the quantized transform coefficients of the quantized transform coefficient block, as well as transform information (such as quantization parameters (QP) and / or (one or more) transform mode indications). Inverse quantization unit 306 can use the QP associated with the quantized transform coefficient block to determine the degree of quantization, and similarly, determine the degree of inverse quantization to be applied by inverse quantization unit 306. Inverse quantization unit 306 can, for example, perform a bitwise left shift operation to inverse quantize the quantized transform coefficients. Inverse quantization unit 306 can thereby form a transform coefficient block including the transform coefficients.

[0176] After the inverse quantization unit 306 forms the transform coefficient block, the inverse transform processing unit 308 can apply one or more inverse transforms to the transform coefficient block to generate a residual block associated with the current block. For example, the inverse transform processing unit 308 can apply an inverse DCT, an inverse integer transform, a Karhunen-Loeve transform (KLT), an inverse rotation transform, an inverse direction transform, or another inverse transform to the transform coefficient block.

[0177] Furthermore, the prediction processing unit 304 generates a prediction block based on the prediction information syntax elements entropy-decoded by the entropy decoding unit 302. For example, if the prediction information syntax elements indicate that the current block is predicted inter-frame, the motion compensation unit 316 can generate the prediction block. In this case, the prediction information syntax elements may indicate a reference image in the DPB 314 from which the reference block is obtained, and a motion vector identifying the position of the reference block in the reference image relative to the current block in the current image. The motion compensation unit 316 can typically be configured substantially with respect to the motion compensation unit 224 ( Figure 3 The inter-frame prediction process is performed in a manner similar to that described above.

[0178] As another example, if the prediction information syntax element indicates that the current block is intra-predicted, then intra-prediction unit 318 can generate a prediction block according to the intra-prediction mode indicated by the prediction information syntax element. Furthermore, intra-prediction unit 318 can generally be configured substantially similarly to intra-prediction unit 226 ( Figure 3 The intra-prediction process is performed in a manner similar to that described above. The intra-prediction unit 318 can obtain data from neighboring samples of the current block from the DPB 314.

[0179] Reconstruction unit 310 can use the prediction block and the residual block to reconstruct the current block. For example, reconstruction unit 310 can add samples from the residual block to the corresponding samples from the prediction block to reconstruct the current block.

[0180] Filtering unit 312 can perform one or more filtering operations on the reconstructed block. For example, filtering unit 312 can perform a deblocking operation to reduce block artifacts along the edges of the reconstructed block. The operation of filtering unit 312 does not need to be performed in all examples.

[0181] The video decoder 300 can store the reconstructed blocks in the DPB 314. For example, in an example where the filtering unit 312 is not operated, the reconstruction unit 310 can store the reconstructed blocks in the DPB 314. In an example where the filtering unit 312 is operated, the filtering unit 312 can store the filtered reconstructed blocks in the DPB 314. As discussed above, the DPB 314 can provide reference information to the prediction processing unit 304, such as samples of the current image for intra-frame prediction and samples of previously decoded images for subsequent motion compensation. Furthermore, the video decoder 300 can output the decoded image (e.g., decoded video) from the DPB 314 for subsequent display on a display device (such as...). Figure 1 It is displayed on the display device 118.

[0182] In this manner, the video decoder 300 represents an example of a video decoding device, comprising: a memory configured to store video data, and one or more processing units implemented in circuitry and configured to: for the current block of video data and using decoder-side intra-mode derivation (DIMD) to derive a list of intra-modes using reconstructed samples from neighboring blocks; for the current block, construct a most probable mode (MPM) list including at least one intra-mode from the derived list of intra-modes; and predict the current block using candidates selected from the constructed MPM list.

[0183] Figure 15 This is a flowchart illustrating an example method for encoding a current block according to the technology of this disclosure. The current block may include the current CU. Although regarding video encoder 200 ( Figure 1 and Figure 3 This has been described, but it should be understood that other devices can be configured to perform the same actions. Figure 15 Similar methods.

[0184] In this example, the video encoder 200 initially predicts the current block (350). For example, the video encoder 200 may form a prediction block for the current block. The video encoder 200 may then compute a residual block for the current block (352). To compute the residual block, the video encoder 200 may compute the difference between the original, uncoded block and the prediction block for the current block. The video encoder 200 may then transform the residual block and quantize the transform coefficients of the residual block (354). Next, the video encoder 200 may scan the quantized transform coefficients of the residual block (356). During or after the scan, the video encoder 200 may entropy encode the transform coefficients (358). For example, the video encoder 200 may use CAVLC or CABAC to encode the transform coefficients. The video encoder 200 may then output the entropy-encoded data of the block (360).

[0185] Figure 16 This is a flowchart illustrating an example method for decoding a current block of video data according to the technology of this disclosure. The current block may include the current CU. Although regarding the video decoder 300 ( Figure 1 and Figure 4 This has been described, but it should be understood that other devices can be configured to perform the same actions. Figure 16 Similar methods.

[0186] The video decoder 300 can receive entropy-coded data of the current block, such as entropy-coded prediction information and entropy-coded data of the transform coefficients of the residual block corresponding to the current block (370). The video decoder 300 can entropy decode the entropy-coded data to determine the prediction information of the current block and reproduce the transform coefficients of the residual block (372). The video decoder 300 can predict the current block (374), for example, using an intra-frame prediction mode or inter-frame prediction mode as indicated by the prediction information of the current block, to compute a prediction block for the current block. The video decoder 300 can then inversely scan the reproduced transform coefficients (376) to create a block of quantized transform coefficients. The video decoder 300 can then inversely quantize the transform coefficients and apply an inverse transform to the transform coefficients to produce a residual block (378). The video decoder 300 can finally decode the current block by combining the prediction block and the residual block (380).

[0187] Figure 17 This is a flowchart illustrating an example technique for encoding video data using DIMD according to one or more techniques of this disclosure. Although regarding video encoder 200 ( Figure 1 and Figure 3 This has been described, but it should be understood that other devices can be configured to perform the same actions. Figure 17 Similar methods.

[0188] The video encoder 200 can derive a list of decoder-side intra-mode derivation (DIMD) intra-modes (1702) for the current block of video data using reconstructed samples from neighboring blocks. For example, the intra-prediction unit 226 can use the above reference... Figure 7 The techniques described are used to derive DIMD intra-frame modes to obtain a first DIMD intra-frame mode M1 and a second DIMD intra-frame mode M2.

[0189] The video encoder 200 can construct a most probable mode (MPM) list for the current block, which includes at least one intra-frame mode (1704) from the DIMD mode. For example, the intra-frame prediction unit 226 can use the above reference. Figure 11 The techniques described are used to construct a list of MPMs. The constructed list of MPMs may include one or both of a first DIMD intra-mode M1 and a second DIMD intra-mode M2.

[0190] The video encoder 200 can determine whether to use DIMD to predict the current block (1706). For example, the mode selection unit 202 can perform analysis to determine the optimal encoding mode for the current block (e.g., the decoding mode that uses the fewest bits to represent the current block). To determine the optimal encoding mode, the mode selection unit 202 can test various modes for encoding the current block. If the mode selection unit 202 determines that using DIMD to encode the current block is optimal, the mode selection unit 202 can determine to use DIMD to encode the current block. Similarly, if the mode selection unit 202 determines that one of the derived DIMD modes in the MPM list is used to encode the current block, the mode selection unit 202 can determine not to use DIMD to encode the current block.

[0191] The video encoder 200 can encode an indication of whether the current block is predicted using DIMD. For example, the entropy coding unit 220 can encode a DIMD flag for the current block with a value indicating whether DIMD is enabled for the current block of video data. As an example, in response to determining that DIMD is not used to predict the current block (the "No" branch of 1706), the video encoder 200 can encode a DIMD flag with a false (e.g., 0) value indicating that the current block is not predicted using DIMD (1708). As another example, in response to determining that DIMD is used to predict the current block (the "Yes" branch of 1706), the video encoder 200 can encode a DIMD flag with a true (e.g., 1) value indicating that the current block is predicted using DIMD (1714).

[0192] The video encoder 200 can encode one or more syntax elements that indicate a selected intra-frame mode from the MPM list (1710). For example, the entropy coding unit 220 can encode syntax elements that have a value indicating an index in the MPM list of the selected intra-frame mode.

[0193] In some examples, as discussed above, the video encoder 200 may include a reconstruction loop in which blocks of video data are reconstructed to be used as a reference when predicting subsequent blocks. As an example, if the current block is not predicted using DIMD, the video encoder 200 may use a selected intra-frame mode to predict the current block (1712). For example, the intra-frame prediction unit 226 may use samples in the direction specified by the selected intra-frame mode to generate the predicted block. As another example, if the current block is predicted using DIMD, the video encoder 200 may use DIMD to predict the current block (1716). For example, the intra-frame prediction unit 226 may use the reference mentioned above. Figure 8 The described technique is used to predict the current block.

[0194] Figure 18 This is a flowchart illustrating an example technique for decoding video data using DIMD according to one or more techniques of this disclosure. Although regarding video decoder 300 ( Figure 1 and Figure 4 This has been described, but it should be understood that other devices can be configured to perform the same actions. Figure 18 Similar methods.

[0195] The video decoder 300 can derive a list of decoder-side intra-mode derivation (DIMD) intra-modes (1802) for the current block of video data using reconstructed samples from neighboring blocks. For example, the intra-prediction unit 318 can use the above reference. Figure 7 The techniques described are used to derive DIMD intra-frame modes to obtain a first DIMD intra-frame mode M1 and a second DIMD intra-frame mode M2.

[0196] The video decoder 300 can construct a most probable mode (MPM) list for the current block, which includes at least one intra-frame mode (1804) from the DIMD mode. For example, the intra-frame prediction unit 318 can use the above reference. Figure 11 The techniques described are used to construct a list of MPMs. The constructed list of MPMs may include one or both of a first DIMD intra-mode M1 and a second DIMD intra-mode M2.

[0197] Video decoder 300 can determine whether to use DIMD to predict the current block (1806). For example, entropy decoding unit 302 can decode the current block pair with a DIMD flag having a value indicating whether DIMD is enabled for the current block of video data. Based on the value of the DIMD flag, intra-prediction unit 318 can determine whether to use DIMD to predict the current block. As an example, if the value of the flag is true (e.g., 1), intra-prediction unit 318 can determine to use DIMD to predict the current block. As another example, if the value of the flag is false (e.g., 0), intra-prediction unit 318 can determine not to use DIMD to predict the current block. As noted above, in some examples, video decoder 300 can deduce a list of DIMD intra-modes regardless of the value of the DIMD flag.

[0198] If the video decoder 300 determines that DIMD is not used to predict the current block (the "No" branch of 1806), the entropy decoding unit 302 may decode one or more syntax elements that indicate a selected intra-mode from the MPM list (e.g., an index in the MPM list) (1808). For example, the entropy decoding unit 302 may decode the intra_luma_mpm_idx syntax element that specifies an index in the MPM list of the selected intra-mode.

[0199] The video decoder 300 can use candidates selected from the constructed MPM list to predict the current block (1810). For example, the intra-prediction unit 318 can use a selected intra-mode from the MPM list to generate a predicted block for the current block. The reconstruction unit 310 can combine the predicted block with the residual block (e.g., similar to...). Figure 16 (of 380).

[0200] If the video decoder 300 determines that DIMD is used to predict the current block (the "yes" branch of 1806), the entropy decoding unit 302 can use DIMD to predict the current block (1812). For example, the intra-frame prediction unit 318 can use the above reference. Figure 8 The described technique is used to predict the current block.

[0201] The following numbered clauses may illustrate one or more examples of this disclosure:

[0202] Clause 1A. A method for decoding video data, the method comprising: for a current block of video data and using decoder-side intra-mode derivation (DIMD) to derive an intra-mode list using reconstructed samples from neighboring blocks; for the current block, constructing a most probable mode (MPM) list, the MPM list including at least one intra-mode from the derived intra-mode list; and using candidates selected from the constructed MPM list to predict the current block.

[0203] Clause 2A. The method according to Clause 1A, wherein deriving the intra-mode list using DIMD includes: using DIMD to derive the intra-mode list regardless of the value of the DIMD flag.

[0204] Clause 3A. The method according to Clause 1A or Clause 2A, wherein constructing the MPM list comprises: inserting a first candidate from an intra-mode list derived using DIMD into the MPM list; and selectively inserting a second candidate into the MPM list based on the sum of the intensities of the second candidates from the intra-mode list derived using DIMD.

[0205] Clause 4A. The method according to Clause 3A, wherein constructing the MPM list further includes: inserting additional intra-mode candidates into the MPM list and after the first candidate.

[0206] Clause 5A. An apparatus for decoding video data, the apparatus comprising: one or more components for performing a method according to any one of Clauses 1A to 4A.

[0207] Clause 6A. A device pursuant to Clause 5A, wherein one or more components include one or more processors implemented in circuitry.

[0208] Clause 7A. A device pursuant to any one of Clauses 5A and 6A further includes: a memory that stores video data.

[0209] Clause 8A. The device pursuant to any one of Clauses 5A to 7A further includes: a display configured to display decoded video data.

[0210] Clause 9A. Devices under any one of Clauses 5A to 8A, wherein the device includes one or more of a camera, computer, mobile device, broadcast receiver device or set-top box.

[0211] Clause 10A. A computer-readable storage medium having instructions stored thereon, which, when executed, cause one or more processors to perform a method according to any one of Clauses 1A to 4A.

[0212] Clause 1B. A method for decoding video data, the method comprising: for a current block of video data and using decoder-side intra-mode derivation (DIMD) to derive an intra-mode list using reconstructed samples from neighboring blocks; for the current block, constructing a most probable mode (MPM) list, wherein constructing the MPM list includes inserting at least one intra-mode from the derived intra-mode list into the MPM list; and using candidates selected from the constructed MPM list to predict the current block.

[0213] Clause 2B. The method according to Clause 1B further includes: decoding a DIMD flag having a value indicating whether DIMD is enabled for the current block of video data, wherein using DIMD to derive the intra-mode list includes using DIMD to derive the intra-mode list regardless of the value of the DIMD flag.

[0214] Clause 3B. The method according to Clause 1B, wherein inserting at least one intra-mode from the derived intra-mode list into the MPM list comprises: inserting a first candidate from the intra-mode list derived using DIMD into the MPM list; and selectively inserting a second candidate from the intra-mode list derived using DIMD into the MPM list.

[0215] Clause 4B. The method according to Clause 3B, wherein selectively inserting a second candidate comprises: selectively inserting a second candidate into the MPM list based on the sum of the intensities of the second candidates from the intra-mode list derived using DIMD.

[0216] Clause 5B. The method according to Clause 1B, wherein constructing the MPM list further comprises: inserting additional intra-mode candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0217] Clause 6B. The method according to Clause 5B, wherein inserting additional intra-mode candidates comprises: inserting one or more default candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0218] Clause 7B. The method according to Clause 5B, wherein constructing the MPM list further comprises: inserting one or more intra-mode candidates as prediction modes from neighboring blocks of the current block into the MPM list and before at least one intra-mode from the derived intra-mode list.

[0219] Clause 8B. A method for encoding video data, the method comprising: for a current block of video data and using decoder-side intra-mode derivation (DIMD) to derive a list of intra-modes using reconstructed samples from neighboring blocks; for the current block, constructing a most probable mode (MPM) list, wherein constructing the MPM list includes inserting at least one intra-mode from the derived list of intra-modes into the MPM list; for the current block and selecting candidate intra-modes from the MPM list; and for the current block, encoding one or more syntax elements of the specified candidate intra-modes.

[0220] Clause 9B. The method pursuant to Clause 8B further includes: encoding a DIMD flag for the current block pair having a value indicating whether DIMD is enabled for the current block of video data, wherein using DIMD to deduce the intra-mode list includes using DIMD to deduce the intra-mode list regardless of the value of the DIMD flag.

[0221] Clause 10B. The method according to Clause 8B, wherein inserting at least one intra-mode from the derived intra-mode list into the MPM list comprises: inserting a first candidate from the intra-mode list derived using DIMD into the MPM list; and selectively inserting a second candidate from the intra-mode list derived using DIMD into the MPM list.

[0222] Clause 11B. The method according to Clause 10B, wherein selectively inserting a second candidate comprises: selectively inserting a second candidate into the MPM list based on the sum of the intensities of the second candidates from the intra-mode list derived using DIMD.

[0223] Clause 12B. The method according to Clause 8B, wherein constructing the MPM list further comprises: inserting additional intra-mode candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0224] Clause 13B. The method according to Clause 12B, wherein inserting additional intra-mode candidates comprises: inserting one or more default candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0225] Clause 14B. The method according to Clause 12B, wherein constructing the MPM list further comprises: inserting one or more intra-mode candidates as prediction modes from neighboring blocks of the current block into the MPM list and before at least one intra-mode from the derived intra-mode list.

[0226] Clause 15B. An apparatus for decoding video data, the apparatus comprising: a memory configured to store video data; and one or more processors implemented in circuitry and configured to: for a current block of video data and using decoder-side intra-mode derivation (DIMD) to derive a list of intra-modes using reconstructed samples from neighboring blocks; for the current block, construct a list of most probable modes (MPMs), wherein constructing the MPM list includes inserting at least one intra-mode from the derived list of intra-modes into the MPM list; and predict the current block using candidates selected from the constructed list of MPMs.

[0227] Clause 16B. A device according to Clause 15B, wherein one or more processors are further configured to: decode a DIMD flag having a value indicating whether DIMD is enabled for the current block of video data, wherein, in order to use DIMD to deduce an intra-mode list, one or more processors are configured to use DIMD to deduce an intra-mode list regardless of the value of the DIMD flag.

[0228] Clause 17B. A device pursuant to Clause 15B, wherein, in order to insert at least one intra-mode from a derived intra-mode list into an MPM list, one or more processors are configured to: insert a first candidate from a DIMD-derived intra-mode list into the MPM list; and selectively insert a second candidate from a DIMD-derived intra-mode list into the MPM list.

[0229] Clause 18B. A device pursuant to Clause 17B, wherein, in order to selectively insert a second candidate, one or more processors are configured to selectively insert a second candidate into an MPM list based on the sum of the intensities of the second candidates from a list of intra-modes derived using DIMD.

[0230] Clause 19B. A device pursuant to Clause 15B, wherein, in order to construct an MPM list, one or more processors are configured to: insert additional intra-mode candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0231] Clause 20B. A device pursuant to Clause 19B, wherein, in order to insert additional intra-mode candidates, one or more processors are configured to: insert one or more default candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0232] Clause 21B. A device pursuant to Clause 19B, wherein, in order to construct an MPM list, one or more processors are configured to: insert one or more intra-mode candidates as prediction modes from neighboring blocks of the current block into the MPM list and before at least one intra-mode from the derived intra-mode list.

[0233] Clause 22B. An apparatus for encoding video data, the apparatus comprising: a memory configured to store video data; and one or more processors implemented in circuitry and configured to: for a current block of video data and using decoder-side intra-mode derivation (DIMD) to derive a list of intra-modes using reconstructed samples from neighboring blocks; for the current block, construct a list of most probable modes (MPMs), wherein constructing the MPM list includes inserting at least one intra-mode from the derived list of intra-modes into the MPM list; for the current block and selecting candidate intra-modes from the MPM list; and for the current block, encoding one or more syntax elements of the specified candidate intra-modes.

[0234] Clause 23B. The apparatus according to Clause 22B, wherein one or more processors are further configured to: encode a DIMD flag having a value indicating whether DIMD is enabled for the current block of video data, wherein, in order to use DIMD to deduce an intra-mode list, one or more processors are configured to use DIMD to deduce an intra-mode list regardless of the value of the DIMD flag.

[0235] Clause 24B. A device pursuant to Clause 22B, wherein, in order to insert at least one intra-mode from a derived intra-mode list into an MPM list, one or more processors are configured to: insert a first candidate from a DIMD-derived intra-mode list into the MPM list; and selectively insert a second candidate from a DIMD-derived intra-mode list into the MPM list.

[0236] Clause 25B. A device pursuant to Clause 24B, wherein, in order to selectively insert a second candidate, one or more processors are configured to selectively insert a second candidate into an MPM list based on the sum of the intensities of the second candidates from a list of intra-modes derived using DIMD.

[0237] Clause 26B. A device pursuant to Clause 22B, wherein, in order to construct an MPM list, one or more processors are configured to: insert additional intra-mode candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0238] Clause 27B. A device pursuant to Clause 26B, wherein, in order to insert additional intra-mode candidates, one or more processors are configured to: insert one or more default candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0239] Clause 28B. A device pursuant to Clause 26B, wherein, in order to construct an MPM list, one or more processors are configured to: insert one or more intra-mode candidates as prediction modes from neighboring blocks of the current block into the MPM list and before at least one intra-mode from the derived intra-mode list.

[0240] Clause 1C. A method for decoding video data, the method comprising: for a current block of video data and using decoder-side intra-mode derivation (DIMD) to derive an intra-mode list using reconstructed samples from neighboring blocks; for the current block, constructing a most probable mode (MPM) list, wherein constructing the MPM list includes inserting at least one intra-mode from the derived intra-mode list into the MPM list; and using candidates selected from the constructed MPM list to predict the current block.

[0241] Clause 2C. The method according to Clause 1C further includes: decoding a DIMD flag having a value indicating whether DIMD is enabled for the current block of video data, wherein using DIMD to deduce the intra-mode list includes using DIMD to deduce the intra-mode list regardless of the value of the DIMD flag.

[0242] Clause 3C. The method according to Clause 1C or 2C, wherein inserting at least one intra-mode from the derived intra-mode list into the MPM list comprises: inserting a first candidate from the intra-mode list derived using DIMD into the MPM list; and selectively inserting a second candidate from the intra-mode list derived using DIMD into the MPM list.

[0243] Clause 4C. The method according to Clause 3C, wherein selectively inserting a second candidate comprises: selectively inserting a second candidate into the MPM list based on the sum of the intensities of the second candidates from the intra-mode list derived using DIMD.

[0244] Clause 5C. The method according to any one of Clauses 1C to 4C, wherein constructing the MPM list further comprises: inserting additional intra-mode candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0245] Clause 6C. The method according to Clause 5C, wherein inserting additional intra-mode candidates comprises: inserting one or more default candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0246] Clause 7C. The method according to Clause 5C or 6C, wherein constructing the MPM list further comprises: inserting one or more intra-mode candidates as prediction modes from neighboring blocks of the current block into the MPM list and before at least one intra-mode from the derived intra-mode list.

[0247] Clause 8C. A method for encoding video data, the method comprising: for a current block of video data and using decoder-side intra-mode derivation (DIMD) to derive a list of intra-modes using reconstructed samples from neighboring blocks; for the current block, constructing a most probable mode (MPM) list, wherein constructing the MPM list includes inserting at least one intra-mode from the derived list of intra-modes into the MPM list; for the current block and selecting candidate intra-modes from the MPM list; and for the current block, encoding one or more syntax elements of the specified candidate intra-modes.

[0248] Clause 9C. The method according to Clause 8C further includes: encoding a DIMD flag having a value indicating whether DIMD is enabled for the current block of video data, wherein using DIMD to deduce the intra-mode list includes using DIMD to deduce the intra-mode list regardless of the value of the DIMD flag.

[0249] Clause 10C. The method according to Clause 8C or 9C, wherein inserting at least one intra-mode from the derived intra-mode list into the MPM list comprises: inserting a first candidate from the intra-mode list derived using DIMD into the MPM list; and selectively inserting a second candidate from the intra-mode list derived using DIMD into the MPM list.

[0250] Clause 11C. The method according to Clause 10C, wherein selectively inserting a second candidate comprises: selectively inserting a second candidate into the MPM list based on the sum of the intensities of the second candidates from the intra-mode list derived using DIMD.

[0251] Clause 12C. The method according to any one of Clauses 8C to 11C, wherein constructing the MPM list further comprises: inserting additional intra-mode candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0252] Clause 13C. The method according to Clause 12C, wherein inserting additional intra-mode candidates comprises: inserting one or more default candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0253] Clause 14C. The method according to Clause 12C or 13C, wherein constructing the MPM list further comprises: inserting one or more intra-mode candidates as prediction modes from neighboring blocks of the current block into the MPM list and before at least one intra-mode from the derived intra-mode list.

[0254] Item 15C. An apparatus for decoding video data, the apparatus comprising: a memory configured to store video data; and one or more processors implemented in circuitry and configured to: for a current block of video data and using decoder-side intra-mode derivation (DIMD) to derive a list of intra-modes using reconstructed samples from neighboring blocks; for the current block, construct a list of most probable modes (MPMs), wherein constructing the MPM list includes inserting at least one intra-mode from the derived list of intra-modes into the MPM list; and predict the current block using candidates selected from the constructed list of MPMs.

[0255] Clause 16C. A device according to Clause 15C, wherein one or more processors are further configured to: decode a DIMD flag having a value indicating whether DIMD is enabled for the current block of video data, wherein, in order to use DIMD to deduce an intra-mode list, one or more processors are configured to use DIMD to deduce an intra-mode list regardless of the value of the DIMD flag.

[0256] Clause 17C. A device pursuant to Clause 15C or 16C, wherein, in order to insert at least one intra-mode from a derived intra-mode list into an MPM list, one or more processors are configured to: insert a first candidate from a DIMD-derived intra-mode list into the MPM list; and selectively insert a second candidate from a DIMD-derived intra-mode list into the MPM list.

[0257] Clause 18C. A device according to Clause 17C, wherein, in order to selectively insert a second candidate, one or more processors are configured to selectively insert a second candidate into an MPM list based on the sum of the intensities of the second candidates from a list of intra-modes derived using DIMD.

[0258] Clause 19C. A device pursuant to any one of Clauses 15C to 18C, wherein, in order to construct an MPM list, one or more processors are configured to insert additional intra-mode candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0259] Clause 20C. A device pursuant to Clause 19C, wherein, in order to insert additional intra-mode candidates, one or more processors are configured to: insert one or more default candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0260] Clause 21C. A device pursuant to Clause 19C or 20C, wherein, in order to construct an MPM list, one or more processors are configured to: insert one or more intra-mode candidates as predicted modes from neighboring blocks of the current block into the MPM list and before at least one intra-mode from the derived intra-mode list.

[0261] Clause 22C. An apparatus for encoding video data, the apparatus comprising: a memory configured to store video data; and one or more processors implemented in circuitry and configured to: for a current block of video data and using decoder-side intra-mode derivation (DIMD) to derive a list of intra-modes using reconstructed samples from neighboring blocks; for the current block, construct a list of most probable modes (MPMs), wherein constructing the MPM list includes inserting at least one intra-mode from the derived list of intra-modes into the MPM list; for the current block and selecting candidate intra-modes from the MPM list; and for the current block, encoding one or more syntax elements of the specified candidate intra-modes.

[0262] Clause 23C. A device according to Clause 22C, wherein one or more processors are further configured to: encode a DIMD flag having a value indicating whether DIMD is enabled for the current block of video data, wherein, in order to use DIMD to deduce an intra-mode list, one or more processors are configured to use DIMD to deduce an intra-mode list regardless of the value of the DIMD flag.

[0263] Clause 24C. A device pursuant to Clause 22C or 23C, wherein, in order to insert at least one intra-mode from a derived intra-mode list into an MPM list, one or more processors are configured to: insert a first candidate from a DIMD-derived intra-mode list into the MPM list; and selectively insert a second candidate from a DIMD-derived intra-mode list into the MPM list.

[0264] Clause 25C. A device according to Clause 24C, wherein, in order to selectively insert a second candidate, one or more processors are configured to selectively insert a second candidate into an MPM list based on the sum of the intensities of the second candidates from a list of intra-modes derived using DIMD.

[0265] Clause 26C. A device pursuant to any one of Clauses 22C to 25C, wherein, in order to construct an MPM list, one or more processors are configured to insert additional intra-mode candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0266] Clause 27C. A device pursuant to Clause 26C, wherein, in order to insert additional intra-mode candidates, one or more processors are configured to: insert one or more default candidates into the MPM list and after at least one intra-mode from the derived intra-mode list.

[0267] Clause 28C. A device pursuant to Clause 26C or 27C, wherein, in order to construct an MPM list, one or more processors are configured to: insert one or more intra-mode candidates as predicted modes from neighboring blocks of the current block into the MPM list and before at least one intra-mode from the derived intra-mode list.

[0268] Clause 1D. A computer-readable storage medium having instructions stored thereon, which, when executed, cause one or more processors of a video decoder to perform a method according to any one of Clauses 1C to 7C.

[0269] Clause 1E. A computer-readable storage medium having instructions stored thereon, which, when executed, cause one or more processors of a video decoder to perform a method according to any one of Clauses 8C to 14C.

[0270] It will be recognized that, depending on the example, certain actions or events of any of the techniques described herein may be performed in a different order, or may be added, combined, or omitted together (e.g., not all described actions or events are necessary for the practice of the technique). Furthermore, in some examples, actions or events may be performed concurrently, for example, through multithreaded processing, interrupt handling, or multiple processors, rather than sequentially.

[0271] In one or more examples, the described functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, these functions may be stored or transmitted as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. A computer-readable medium may include: a computer-readable storage medium corresponding to a tangible medium such as a data storage medium, or a communication medium that includes, for example, any medium facilitating the transfer of a computer program from one place to another according to a communication protocol. In this way, a computer-readable medium may generally correspond to (1) a non-transitory tangible computer-readable storage medium, or (2) a communication medium such as a signal or carrier wave. A data storage medium may be any available medium accessible by one or more computers or one or more processors to obtain instructions, code, and / or data structures for implementing the techniques described in this disclosure. Computer program products may include computer-readable media.

[0272] For example, and not as a limitation, such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Furthermore, any connection is properly referred to as a computer-readable medium. For example, coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies (such as infrared, radio, and microwave) are included in the definition of medium if the instructions are transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies (such as infrared, radio, and microwave). However, it should be understood that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transient media, but rather refer to non-transient, tangible storage media. As used herein, disks and platters include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks typically magnetically reproduce data, while platters optically reproduce data using lasers. The combinations described above should also be included within the scope of computer-readable media.

[0273] Instructions can be executed by one or more processors, such as one or more DSPs, general-purpose microprocessors, ASICs, FPGAs, or other equivalent integrated or discrete logic circuits. Accordingly, the terms "processor" and "processing circuit" as used herein can refer to any of the foregoing structures or any other structure suitable for implementing the techniques described herein. Furthermore, in some aspects, the functionality described herein can be provided within dedicated hardware and / or software modules configured for encoding and decoding, or incorporated into combined codecs. Moreover, these techniques can be entirely implemented within one or more circuit or logic elements.

[0274] The techniques disclosed herein can be implemented in a variety of devices or apparatuses, including wireless handheld devices, integrated circuits (ICs), or IC sets (e.g., chipsets). Various components, modules, or units are described in this disclosure to emphasize functional aspects of a device configured to perform the disclosed techniques, but implementation by different hardware units is not necessarily required. Rather, as described above, various units can be combined in a codec hardware unit, or provided by a collection of interoperable hardware units including one or more processors as described above, in conjunction with suitable software and / or firmware.

[0275] Various examples have been described. These and other examples are all within the scope of the appended claims.

Claims

1. A method for decoding video data, the method comprising: For the current block of video data, and using decoder-side intra-mode derivation DIMD to derive the intra-mode list using reconstructed samples from neighboring blocks; For the current block, a most probable mode (MPM) list is constructed, wherein constructing the MPM list includes inserting at least one intra-mode from the derived intra-mode list into the MPM list, and wherein inserting the at least one intra-mode from the derived intra-mode list into the MPM list includes: Insert a first candidate from the intra-mode list derived using DIMD into the MPM list; and Selectively insert a second candidate from the intra-mode list derived using DIMD into the MPM list; and The current block is predicted using candidates selected from the constructed MPM list.

2. The method according to claim 1, further comprising: Decoding the current block pair with a DIMD flag having a value indicating whether DIMD is enabled for the current block of video data, wherein using DIMD to deduce the intra-frame mode list includes using DIMD to deduce the intra-frame mode list regardless of the value of the DIMD flag.

3. The method according to claim 1, wherein, Selectively inserting the second candidate includes: selectively inserting the second candidate into the MPM list based on the sum of the intensities of the second candidates from the intra-mode list derived using DIMD.

4. The method according to claim 1, wherein, Constructing the MPM list also includes: Additional intra-mode candidates are inserted into the MPM list and after the at least one intra-mode from the derived intra-mode list.

5. The method according to claim 4, wherein, The additional intra-frame mode candidates to be inserted include: One or more default candidates are inserted into the MPM list and after the at least one intra-mode from the derived intra-mode list.

6. The method according to claim 4, wherein, Constructing the MPM list also includes: One or more intra-mode candidates, which are prediction modes from neighboring blocks of the current block, are inserted into the MPM list and before the at least one intra-mode from the derived intra-mode list.

7. A method for encoding video data, the method comprising: For the current block of video data, and using decoder-side intra-mode derivation DIMD to derive the intra-mode list using reconstructed samples from neighboring blocks; For the current block, a most probable mode (MPM) list is constructed, wherein constructing the MPM list includes inserting at least one intra-mode from the derived intra-mode list into the MPM list, and wherein inserting the at least one intra-mode from the derived intra-mode list into the MPM list includes: Insert a first candidate from the intra-mode list derived using DIMD into the MPM list; and A second candidate from the intra-mode list derived using DIMD is selectively inserted into the MPM list; For the current block and select candidate intra-frame modes from the MPM list; and The current block encodes one or more syntax elements that specify the candidate intra-frame mode.

8. The method according to claim 7, further comprising: The current block pair is encoded with a DIMD flag that indicates whether DIMD is enabled for the current block of video data, wherein using DIMD to deduce the intra-frame mode list includes using DIMD to deduce the intra-frame mode list regardless of the value of the DIMD flag.

9. The method according to claim 7, wherein, Selectively inserting the second candidate includes: selectively inserting the second candidate into the MPM list based on the sum of the intensities of the second candidates from the intra-mode list derived using DIMD.

10. The method according to claim 7, wherein, Constructing the MPM list also includes: Additional intra-mode candidates are inserted into the MPM list and after the at least one intra-mode from the derived intra-mode list.

11. The method according to claim 10, wherein, The additional intra-frame mode candidates to be inserted include: One or more default candidates are inserted into the MPM list and after the at least one intra-mode from the derived intra-mode list.

12. The method according to claim 10, wherein, Constructing the MPM list also includes: One or more intra-mode candidates, which are prediction modes from neighboring blocks of the current block, are inserted into the MPM list and before the at least one intra-mode from the derived intra-mode list.

13. An apparatus for decoding video data, the apparatus comprising: A memory configured to store video data; as well as One or more processors, said one or more processors being implemented in circuitry and configured to: For the current block of video data, and using decoder-side intra-mode derivation DIMD to derive the intra-mode list using reconstructed samples from neighboring blocks; For the current block, a most probable mode (MPM) list is constructed, wherein constructing the MPM list includes inserting at least one intra-frame mode from the derived intra-frame mode list into the MPM list, and wherein, in order to insert the at least one intra-frame mode from the derived intra-frame mode list into the MPM list, the one or more processors are configured to: Insert a first candidate from the intra-mode list derived using DIMD into the MPM list; and Selectively insert a second candidate from the intra-mode list derived using DIMD into the MPM list; and The current block is predicted using candidates selected from the constructed MPM list.

14. The device according to claim 13, wherein, The one or more processors are further configured to: The current block pair is decoded with a DIMD flag having a value indicating whether DIMD is enabled for the current block of video data, wherein, in order to use DIMD to deduce the intra-frame mode list, the one or more processors are configured to use DIMD to deduce the intra-frame mode list regardless of the value of the DIMD flag.

15. The device according to claim 13, wherein, In order to selectively insert the second candidate, the one or more processors are configured to selectively insert the second candidate into the MPM list based on the sum of the intensities of the second candidates from the intra-mode list derived using DIMD.

16. The device according to claim 13, wherein, In order to construct the MPM list, the one or more processors are configured to: Additional intra-mode candidates are inserted into the MPM list and after the at least one intra-mode from the derived intra-mode list.

17. The device according to claim 16, wherein, In order to insert the additional intra-frame mode candidate, the one or more processors are configured to: One or more default candidates are inserted into the MPM list and after the at least one intra-mode from the derived intra-mode list.

18. The device according to claim 16, wherein, In order to construct the MPM list, the one or more processors are configured to: One or more intra-mode candidates, which are prediction modes from neighboring blocks of the current block, are inserted into the MPM list and before the at least one intra-mode from the derived intra-mode list.

19. An apparatus for encoding video data, the apparatus comprising: A memory configured to store video data; as well as One or more processors, said one or more processors being implemented in circuitry and configured to: For the current block of video data, and using decoder-side intra-mode derivation DIMD to derive the intra-mode list using reconstructed samples from neighboring blocks; For the current block, a most probable mode (MPM) list is constructed, wherein constructing the MPM list includes inserting at least one intra-frame mode from the derived intra-frame mode list into the MPM list, and wherein, in order to insert the at least one intra-frame mode from the derived intra-frame mode list into the MPM list, the one or more processors are configured to: Insert a first candidate from the intra-mode list derived using DIMD into the MPM list; and A second candidate from the intra-mode list derived using DIMD is selectively inserted into the MPM list; For the current block and select candidate intra-frame modes from the MPM list; and The current block encodes one or more syntax elements that specify the candidate intra-frame mode.

20. The device according to claim 19, wherein, The one or more processors are further configured to: The current block pair is encoded with a DIMD flag having a value indicating whether DIMD is enabled for the current block of video data, wherein, in order to use DIMD to deduce the intra-frame mode list, the one or more processors are configured to use DIMD to deduce the intra-frame mode list regardless of the value of the DIMD flag.

21. The device according to claim 19, wherein, In order to selectively insert the second candidate, the one or more processors are configured to selectively insert the second candidate into the MPM list based on the sum of the intensities of the second candidates from the intra-mode list derived using DIMD.

22. The device according to claim 19, wherein, In order to construct the MPM list, the one or more processors are configured to: Additional intra-mode candidates are inserted into the MPM list and after the at least one intra-mode from the derived intra-mode list.

23. The device according to claim 22, wherein, In order to insert the additional intra-frame mode candidate, the one or more processors are configured to: One or more default candidates are inserted into the MPM list and after the at least one intra-mode from the derived intra-mode list.

24. The device according to claim 22, wherein, In order to construct the MPM list, the one or more processors are configured to: One or more intra-mode candidates, which are prediction modes from neighboring blocks of the current block, are inserted into the MPM list and before the at least one intra-mode from the derived intra-mode list.

25. A computer program product comprising computer-readable instructions, which, when executed by one or more processors, cause the one or more processors to perform the method of any one of claims 1 to 6.

26. A computer program product comprising computer-readable instructions, which, when executed by one or more processors, cause the one or more processors to perform the method of any one of claims 7 to 12.

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