Method and apparatus for deblocking an image

Abstract

To provide an apparatus, a method, and a program for deblocking an image.SOLUTION: A method for deblocking an image includes: determining at least one boundary between a first block of a sample and a second block of the sample; determining boundary strength (BS) according to at least one of a prediction mode for the first block and a prediction mode for the second block; and filtering, according to the boundary strength, the first block and the second block of the sample adjacent to the at least one boundary on the basis of a deblocking filter (DBF). When the prediction mode for the first block is a weighted prediction mode, the boundary strength depends on the relative weight of the sample used in predicting the first block of the sample according to the weighted prediction mode for the first block. The same applies to the second block.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] Technical Field At least one of the present embodiments relates generally to, for example, a method or apparatus for video encoding or decoding, and more particularly to a method or apparatus for deblocking an image. [Background technology]

[0002] background The technical field of one or more implementations relates generally to video compression. At least some embodiments relate to improving compression efficiency over existing video compression systems such as HEVC (HEVC refers to High Efficiency Video Coding, also known as H.265 and MPEG-H Part 2, as described in "ITU-T H.265 Telecommunications Standardization Sector of the ITU (10 / 2014), Series H: Audiovisual and Multimedia Systems, Infrastructure for Audiovisual Services - Coding of Moving Images, High Efficiency Video Coding, Recommendation ITU-T H.265") or over developing video compression systems such as VVC (Versatile Video Coding, an emerging standard being developed by JVET, the Joint Video Experts Team).

[0003] To achieve high compression efficiency, image and video coding schemes typically employ image segmentation, prediction, including motion vector prediction, and transforms to exploit spatial and temporal redundancies in video content. Generally, intra- or inter-prediction is used to exploit intra- or inter-frame correlations, and then the difference between the original and predicted image, often denoted as prediction error or prediction residual, is transformed into frequency-domain coefficients, which are quantized and entropy coded. To reconstruct the video, the compressed data is decoded by the inverse processes corresponding to entropy decoding, inverse quantization, inverse transform, and prediction.

[0004] In codecs such as HEVC or VVC, a deblocking filter (DBF) is applied after a picture is reconstructed to reduce blocking artifacts by smoothing sample values ​​near block edges. The deblocking filter is defined using a traditional square or rectangular block division shape with a size equal to at least four luma samples. Next, the selection of motion vectors, reference indices, and reference deblocking samples to be used for determining the deblocking filter strength is performed. For example, Norkin et al. describe the principle of deblocking in "HEVC Deblocking Filter" (IEEE Transactions on Circuits and Systems for Video Technology, vol. 22 No. 12, December 2012).

[0005] Modern video codec approaches consider new coding (prediction) modes in which prediction samples are constructed using combinations of non-square or non-rectangular blocks (e.g., triangles) and / or unequal (e.g., Generalized Bi-Prediction (GBi), also referred to as Bi-Prediction with CU Level Weights (BCW)) and / or spatially variable weighting (e.g., Multiple Hypothesis or Combined Inter-merge Intra Prediction (CIIP)). Therefore, it is desirable to adapt the deblocking filter process to such coding modes in order to still efficiently reduce blocking artifacts. Summary of the Invention

[0006] overview SUMMARY OF THE INVENTION It is an object of the present invention to overcome at least one of the disadvantages of the prior art. [Means for solving the problem]

[0007] For this purpose, according to a general aspect of at least one embodiment, a method for deblocking a portion of an image is presented. The method includes: determining at least one boundary between a first block of samples and a second block of samples, where the first block and the second block belong to a portion of the image to be filtered; determining a boundary strength according to at least one of a prediction mode of the first block and a prediction mode of the second block; and filtering the at least one boundary according to the boundary strength, i.e., filtering samples of the first and second blocks adjacent to the at least one boundary. If the prediction mode of the first block is a weighted prediction mode, the boundary strength further depends on the relative weights of the samples used in predicting the first block of samples according to the weighted prediction mode of the first block. Of course, the same applies to the second block without distinction: if the prediction mode of the second block is a weighted prediction mode, the boundary strength further depends on the relative weights of the samples used in predicting the second block of samples according to the weighted prediction mode of the second block. A weighted prediction mode is a coding mode in which the prediction is obtained from a weighted combination of a first predictor determined using a first prediction mode and a second predictor determined using a second prediction mode.

[0008] According to another general aspect of at least one embodiment, a method for encoding a block in image coding is presented, the method comprising: reconstructing an image portion; and filtering the reconstructed image portion according to any of the embodiments of the deblocking method.

[0009] According to another general aspect of at least one embodiment, a method is presented for decoding a block of an image, the method including decoding a portion of the image and filtering the decoded image portion according to any of the embodiments of a deblocking method.

[0010] According to another general aspect of at least one embodiment, an apparatus for video encoding is presented, the apparatus comprising means for performing any of the embodiments of the encoding method.

[0011] According to another general aspect of at least one embodiment, an apparatus for video decoding is presented, the apparatus comprising means for performing any of the embodiments of the decoding method.

[0012] According to another general aspect of at least one embodiment, there is provided an apparatus for video encoding, the apparatus comprising: one or more processors and at least one memory, the one or more processors configured to perform any of the embodiments of the encoding method.

[0013] According to another general aspect of at least one embodiment, there is provided an apparatus for video decoding, the apparatus comprising: one or more processors configured to perform any of the embodiments of the decoding method; and at least one memory.

[0014] According to another general aspect of at least one embodiment, the weighted prediction mode is one of generalized bidirectional prediction, bidirectional prediction with coding unit level weights, multi-hypothesis prediction combining intra- and inter-predicted samples or combining inter- and inter-predicted samples, combined inter-merge-intra prediction combining inter-merge and intra-predicted samples, geometric prediction combining inter-predicted samples according to a geometric partitioning of the block, and triangular prediction combining inter-predicted samples along diagonal edges of the block.

[0015] According to another general aspect of at least one embodiment, predicting the first block of samples according to a weighted prediction mode for the first block includes predicting the samples of the first block as a weighted combination of a first predictor determined using the first prediction mode and a second predictor determined using the second prediction mode, and the samples of the first block are considered to use the first prediction mode for determining boundary strength if a weight of the first predictor is above a level.

[0016] According to another general aspect of at least one embodiment, the first prediction mode is an intra prediction mode, and samples of the first block are considered to use the intra prediction mode to determine the boundary strength. In one variant, the first prediction mode is an intra planar prediction mode, and samples of the first block are considered to use the intra prediction mode to determine the boundary strength. In one variant, in the case of the intra prediction mode, the boundary strength is set to strong.

[0017] According to another general aspect of at least one embodiment, the first prediction mode is an inter prediction mode, and samples of the first block are considered to use the inter prediction mode to determine the boundary strength. In one variation, the first prediction mode is an inter bidirectional prediction mode, and samples of the first block are considered to use the inter bidirectional prediction mode to determine the boundary strength. In another variation, the first prediction mode is an inter unidirectional prediction mode, and samples of the first block are considered to use the inter unidirectional prediction mode to determine the boundary strength.

[0018] According to another general aspect of at least one embodiment, the level in the BS's decision is set to zero.

[0019] According to another general aspect of at least one embodiment, the boundary strength is determined for a group of samples of a block that share the same relative weight, where the group of samples includes at least one sample, 4x4 samples, up to all samples of the block.

[0020] According to another general aspect of at least one embodiment, a non-transitory computer-readable medium is presented that includes data content generated according to the method or apparatus of any of the foregoing descriptions.

[0021] According to another general aspect of at least one embodiment, there is provided a signal or bitstream including video data generated in accordance with the method or apparatus of any of the preceding descriptions.

[0022] One or more of the present embodiments also provide a computer-readable storage medium having stored thereon instructions for deblocking, encoding, or decoding video data according to any of the above-described methods. The present embodiments also provide a computer-readable storage medium having stored thereon a bitstream generated according to the above-described methods. The present embodiments also provide methods and apparatus for transmitting a bitstream generated according to the above-described methods. The present embodiments also provide a computer program product including instructions for performing any of the above-described methods. [Brief explanation of the drawings]

[0023] BRIEF DESCRIPTION OF THE DRAWINGS [Figure 1a] FIG. 1a shows an exemplary flow chart of an in-loop post-filtering stage in a decoder architecture. [Figure 1b] FIG. 1b shows an example of a decoded image before (left) and after (right) a deblocking filter. [Figure 2] FIG. 2 shows an example of a block boundary sample (left) with blocking artifacts between two blocks of samples (right). [Figure 3] FIG. 3 shows an exemplary flowchart of the determination of the Boundary Strength (BS) parameter in a deblocking filter method according to a particular embodiment. [Figure 4] FIG. 4 shows an exemplary flowchart of determining the filter strength (FS) in a deblocking filter method according to a particular embodiment. [Figure 5] FIG. 5 shows an example of multiple hypothesis prediction for a combination of inter and intra modes. [Figure 6] FIG. 6 shows an example of a non-rectangular partitioning (top) and an example of overlapped block motion compensation diagonal weighting (bottom) associated with a triangular partitioning. [Figure 7] FIG. 7 illustrates an example of a triangle logical partitioning (left) and a blending map (right) according to a particular embodiment. [Figure 8] FIG. 8 illustrates an example method for deblocking portions of an image according to a general aspect of at least one embodiment. [Figure 9] FIG. 9 shows a flowchart of the boundary strength determination in the method of the deblocking filter according to a particular embodiment. [Figure 10] FIG. 10 shows two flowcharts of the storage of CU parameters used in determining the boundary strength (BS) parameter in a deblocking filter method according to a particular embodiment. [Figure 11] FIG. 11 shows a block diagram of an embodiment of a video encoder in which various aspects of the embodiments may be implemented. [Figure 12] FIG. 12 shows a block diagram of an embodiment of a video decoder in which various aspects of the embodiments may be implemented. [Figure 13] FIG. 13 shows a block diagram of an exemplary device in which various aspects of the embodiments may be implemented. DETAILED DESCRIPTION OF THE INVENTION

[0024] Detailed Description It should be understood that the figures and descriptions have been simplified to illustrate relevant elements for a clear understanding of the present principles, while excluding, for purposes of clarity, many other elements found in a typical encoding and / or decoding device. While the terms first and second may be used herein to describe various elements, it will be understood that these elements should not be limited by these terms. These terms are merely used to distinguish one element from another.

[0025] Various embodiments are described with respect to encoding / decoding an image, which may be applied to encoding / decoding portions of an image, such as slices or tiles, groups of tiles, or entire sequences of images.

[0026] Various methods are described above, each of which includes one or more steps or actions for achieving the method described above. Unless a specific order of steps or actions is required for the proper operation of the method, the order and / or use of specific steps and / or actions may be varied or combined.

[0027] At least some embodiments relate to adapting the deblocking filter DBF when a block is coded using one of the following three prediction modes: Generalized Bidirectional Prediction (GBi) or Bidirectional Prediction with CU-Level Weights (BCW), A simplified version called Multi-Hypothesis (MH), or Combined Inter-Merge Intra-Prediction (CIIP), Geometric or triangular mode.

[0028] Advantageously, the present principles increase the efficiency of prior art methods by preserving the intent and efficiency of DBF in block-based video codecs where non-square or non-rectangular blocks are supported and / or where combinations of blocks with variable weightings are supported.

[0029] In the following, a general embodiment for the deblocking method is disclosed, and at least three prediction modes to which the deblocking filter is adapted are disclosed. Then, several embodiments of modified deblocking filters are disclosed.

[0030] General embodiment for a deblocking method and exemplary prediction modes to which the deblocking filter is adapted Traditional video coding schemes include an in-loop filtering process to improve the quality of reconstructed images. In-loop filtering can include several filtering processes, such as deblocking filtering (DBF), sample adaptive offset (SAO) filtering in HEVC, and / or adaptive loop filtering (ALF), such as a Wiener filter. These filters can be applied sequentially in this order or in a different order. FIG. 1a shows an example flowchart of the in-loop post-filtering stage in a decoder architecture. Typically, a deblocking filter (DBF) is one of the coding artifact reduction post-filters (20) and is applied after block samples are reconstructed (10). The post-filtered picture can be displayed and possibly stored in a decoded picture buffer (30) for use in building motion-compensated predictions. Advantageously, the same in-loop post-filtering is also used in the encoder for reconstructed images used in temporal prediction.

[0031] Figure 1b shows an example of a decoded image before (left) and after (right) a deblocking filter. The deblocking filter is applied after the picture is reconstructed (10). Its purpose is to reduce blocking artifacts by smoothing sample values ​​near block edges, as shown on Figure 1b.

[0032] Figure 2 shows an example of a block boundary sample (left) with blocking artifacts between two blocks of samples P and Q (right). Samples P={p0, p1, p2, p3} and Q={q0, q1, q2, q3} belong to two adjacent blocks P and Q. The samples belong to square 4x4 blocks P and Q as shown on the right side of Figure 2, where sample P={p0 i ,p1 i,p2 i ,p3 i The second subscript i in} is the row subscript in the 4x4 block. Generally, the visibility of the artifact is proportional to the relative difference between the sample values ​​P and Q as shown on the left side of Figure 2. That is why DBF filtering performs a sample smoothing S across the block edges. The parameters of the smoothing / filtering function S are: - Border Strength (BS) = {0-weak, 1-normal, or 2-strong} - Sample values ​​of blocks P and Q

[0033] The determination of DBF parameters for a square block is done by dividing the set of row (or column) samples on each side of the vertical (or horizontal, respectively) boundary by p3 i ,p2 i ,p1 i ,p0 i ,q0 i ,q1 i ,q2 i ,q3 i} is performed every}.

[0034] 3 shows an example flowchart 300 of determining a boundary strength (BS) parameter in a deblocking filter method according to a particular embodiment. X ,ref-i X Let {MV value and reference index for list "i" for block X (X=P or Q). By convention, if block X is unidirectionally predicted using list 0, then {MV0 X is set to 0, ref-0 X is set to "-1"}. Separately, if block X is unidirectionally predicted using list 1, then {MV1 X is set to 0, ref-1 X is set to "-1"}.

[0035] The determination 300 of the boundary strength BS depends on several block parameters and is the result of a series of checks, for example: (305): P or Q is intra (otherwise, it is considered as inter). If the check result is no, then both P and Q blocks are inter predicted using the associated motion vectors and reference index pictures, and a further check is performed to determine BS. If P or Q is intra, the check result is yes, and BS is set to 2-strong. - (310): P or Q has a non-zero coefficient and the boundary is a transform boundary. - (320): P and Q have different reference indices. Therefore, by a non-limiting example, P is bi-predicted ({MV0 P ,ref-0 P},{MV1 P ,ref-1 P}), Q is unidirectionally predicted {MV0 Q ,ref-0 Q}If so, then check if: ref-0 P ≠ref-0 Q And ref-1 P ≠ref-0 Q (Check 1) (330): P and Q have different numbers of references (unidirectional or bi-predictive). In one variant, (330) does not exist and in unidirectional the MV value of the missing reference is inferred to be 0. (340): The motion vectors of P and Q with the same reference have different values. Therefore, according to a non-limiting example, P is bi-predicted ({MV0 P ,ref-0 P},{MV1 P ,ref-1 P}), Q is unidirectionally predicted {MV0 Q ,ref-0 Q}If so, then check if: ref-0 P =ref-0 Q And |MV0 P -MV0 Q |>Is it a threshold? or ref-1 P =ref-0 Q And |MV1 P -MV0 Q |>Is it a threshold? (Check 2) Those skilled in the art will unambiguously derive the check for the case of two bidirectionally predicted blocks or two unidirectionally predicted blocks from the above formula for (check 2).

[0036] For blocks of luma samples, only block boundaries with BS equal to 1 or 2 are filtered. For blocks of chroma samples, only block boundaries with BS equal to 2 are filtered.

[0037] 4 shows an exemplary flow chart of the filter strength determination in a deblocking filter method according to a particular embodiment. Therefore, independent of how BS is determined (300), an additional test (415) determines whether filtering is applied or not based on a set of conditions including a combination of the absolute difference of the weighted sample values ​​compared to a predetermined threshold β: |p20-2p10+p00|+|p23-2p13+p03|+|q20-2q10+q00|+|q23-2q13+q03|>β (Equation 1)

[0038] When a filter is applied, the filtering process (430) modifies one or more of the P and Q samples on each side of the boundary in Figure 2 depending on the sample values ​​(410, which accesses the sample values). The strength of the filtering process (normal or strong) is determined for each row (and separately, column) of samples on each side of the boundary (420) based on a set of conditions that include a combination of the absolute difference of the weighted sample values ​​compared to predetermined thresholds. Some thresholds are a function of the quantization parameter (QP) (440).

[0039] The number of samples modified by (430) on each side of the block boundary depends on the filter strength: the stronger the filter, the more pixels it affects on each side of the block boundary.

[0040] At least three new prediction modes are now disclosed, including weighted prediction with unequal or spatially varying weights within a block, in which the deblocking filter is adapted.

[0041] The first prediction mode to which the deblocking filter is adapted: Generalized Bidirectional Prediction (GBI) In the case of bi-prediction, two prediction blocks are calculated and combined with a weighted sum to obtain the final block prediction: P GBI =(((1<<gs)-gw1).P0+gw1.P1)> >gs (Equation 2)

[0042] In the VVC reference software (VTM), the weight to use is coded for each CU using a "gbi index" whose values ​​are shown in Table 1.

[0043] [Table 1]

[0044] In the following, the weight pair {1 / 2;1 / 2} will be called the default weights.

[0045] Second prediction mode in which the deblocking filter is adapted: multiple hypotheses The general concept of Multi Hypothesis MH is to combine an inter prediction P0 (which can be unidirectional or bidirectional) performed in merge mode (where a list of merge candidates {reference index, motion value} is constructed and a merge index identifying one candidate is signaled to obtain motion information for motion compensated inter prediction) with another prediction P1, which is either an intra prediction (MH-inter-intra) or another inter prediction (MH-inter-inter: e.g., unidirectional prediction AMVP, skip and merge). The final prediction is a weighted average of the prediction generated by the merge indexed prediction and the other prediction mode (intra or inter), where different weights are applied depending on the combination.

[0046] FIG. 5 shows an example of multi-hypothesis prediction for the case of the combination of inter and intra modes MH-inter-intra. The intra prediction mode is signaled (it can be a subset (e.g., 4) of the classical prediction modes). The weight w_intra(y) gradually decreases as the region gets farther from the intra reference sample. By way of a non-limiting example, the current block is divided into four equal-area regions sharing the same weighting: (w0=w_intra i ,w1=w_inter iEach weight set, denoted as w0 = w_intra = ½ and w1 = w_inter = ½, where i is 1 to 4, is applied to a corresponding region, as shown in the example of FIG. 5 for intra-vertical prediction. When DC or planar mode is selected or the width or height of the CU is smaller than 4, equal weights are applied. In other words, when the intra-prediction mode of prediction P1 is DC or planar mode, the relative weights used in predicting any sample of the current block are w0 = w_intra = ½ and w1 = w_inter = ½. Therefore, there is only one region of equal weights (i = 1). The coding mode defined in VVC, Combined Inter-Merge Intra Prediction CIIP, is a specific instance of MH-Inter-Intra that combines the inter prediction P0 (which can be unidirectional or bidirectional) performed in merge mode with another prediction P1, which is a planar intra prediction with equal weight 1 / 2.

[0047] According to another example of multiple hypothesis prediction in the case of the inter and inter mode combination MH-inter-inter, the weights are the default ones (1 / 2; 1 / 2). According to another variant of the MH-inter-inter mode, one or two of the inter modes are bi-predictive {2 MV, 2 reference}, so that the construction of the sample prediction requires up to four motion compensation calculations.

[0048] The third prediction mode in which the deblocking filter is adapted: geometric partitioning Geometric (e.g., triangular) modes allow for more flexibility in dividing a picture into blocks before encoding. Figure 6 shows an example of a non-rectangular partition (top) and an example of diagonal weighting for overlapping block motion compensation associated with triangular partitioning (bottom). The top two left examples of Figure 6 represent triangular partitioning, while the top four right examples of Figure 6 represent a more general scheme of geometric partitioning. Further coding performance can be achieved when blending overlapping boundaries, for example, along the diagonal edges shown at the bottom of Figure 6. Thus, luma samples located on the diagonal of a block with a weighting factor of 4 use equal weights of 1 / 2 (W1 = W2 = 4 / 8 = 1 / 2), while diagonally adjacent luma samples of the block with a weighting factor of 2 use weights (W1 = 2 / 8 = 1 / 4 and W2 = 6 / 8 = 3 / 4). In some variations, this weighting process is cascaded with other weightings, such as GBI or Local Illumination Compensation (LIC), increasing implementation complexity.

[0049] In the case of triangulation, the samples can be divided into two groups: - Samples predicted using unidirectional motion compensation (P0 or P1) - Bi-predictive motion compensation, samples predicted using a mixture of uni-predictive P0 and uni-predictive P1.

[0050] As previously explained, at least these three coding modes that use weighted prediction create problems in assessing boundary strength or filter strength in the deblocking filter.

[0051] Some embodiments of a modified deblocking filter adapted to new prediction modes At least one embodiment of the present principles relates to modifying the deblocking filter DBF when blocks are coded using combinations of non-square or non-rectangular blocks (e.g., triangles) and / or combinations of unequal (e.g., GBi) and / or spatially varying weightings (e.g., MH). Advantageously, non-square or non-rectangular blocks, as shown for triangular decomposition, or more generally for geometric decomposition, are considered as a combination of two predictions with spatially varying weightings as shown on Figure 7.

[0052] Advantageously, in at least one embodiment, the DBF process (filter strength derivation and filtering) is modified to preserve the intent and efficiency of the original DBF, thus increasing its efficiency compared to prior art methods.

[0053] FIG. 8 illustrates an example of a method for deblocking a portion of an image according to a general aspect of at least one embodiment. According to a preliminary step S110, information about two adjacent blocks is accessed. The two adjacent blocks will subsequently be referred to as a first block P and a second block Q, which are interchangeable without limitation. While the terms first and second may be used herein to describe two blocks, these two blocks should not be limited by these terms. These terms are merely used to distinguish one element from another. The first block P and the second block Q belong to a portion of the image to be filtered. The block of samples is, by way of non-limiting example, one of a coding unit or a transform unit. In a first step S120, at least one boundary between the first block of samples P and the second block of samples Q is determined. In a particular embodiment, a flag EdgeFlag is set to 1 for samples at the boundary that should be filtered using a DBF, and the flag EdgeFlag is set to 0 for samples that should not be filtered using a DBF. Samples that should not be filtered using the DBF include samples at the boundary of an image or a slice, or samples (non-boundary samples) inside a block, e.g., a coding unit or a transform unit. The boundary is either a horizontal boundary (horizontal edge) or a vertical boundary (vertical edge). In step S130, at least one parameter of the DBF is determined. As previously indicated, the at least one parameter of the DBF includes the boundary strength BS and the filter strength FS of the filter. The boundary strength BS is selected among the values ​​of weak (BS=0), normal (BS=1), or strong (BS=2). The filter strength FS refers to the result of a decision process regarding whether to apply a filter, which affects more or less pixels on each side of the block boundary. The decision process includes at least one condition regarding the values ​​of the samples of the first block P and the second block Q. In step S140, the boundary strength BS is determined according to at least one of the prediction mode of the first block and the prediction mode of the second block.Advantageously, the boundary strength BS is adapted for a prediction mode that is a weighted prediction mode combining a first prediction with a second prediction. According to a particular feature, if the prediction mode of the first block is a weighted prediction mode, the boundary strength BS further depends on the relative weights of the samples used in predicting the first block of samples according to the weighted prediction mode of the first block. According to a particular feature, the weighted prediction mode is one of the previously described coding modes, including generalized bidirectional prediction GBi, also referred to as bidirectional prediction with coding unit level weights BCW, a multi-hypothesis prediction that combines intra- and inter-predicted samples (MH-inter-intra) or a multi-hypothesis prediction that combines inter- and inter-predicted samples (MH-inter-inter), a combined inter-merge-intra prediction that combines inter-merge and intra-predicted samples, a geometric prediction that combines inter-predicted samples according to a geometric division of the block, or a triangular prediction that combines inter-predicted samples along the diagonal edges of the block. In the following, various embodiments for determining the boundary strength BS are described. According to a particular embodiment, predicting the first block of samples according to the weighted prediction mode of the first block comprises predicting the samples of the first block as a weighted combination (w0, w1=1-w0) of a first predictor P0 determined using the first prediction mode and a second predictor P1 determined using the second prediction mode, wherein the samples of the first block are considered to use the first prediction mode for determining boundary strength if the weight w0 of the first predictor exceeds level. According to another particular embodiment, the number of samples in the block having the weight w0 of the first predictor exceeds level, and the BS determines the mode to be used for the first block. According to a particular variant, level is set to 0. According to another particular variant, the boundary strength is determined for a group of samples of the block that share the same relative weight. According to a non-limiting example, the group of samples includes one sample, or 4x4 samples, and up to all samples of the block.Next, in step S160, a DBF filtering process is applied to the first and second blocks along the boundary according to the determined boundary strength BS.

[0054] In previous approaches, the selection of DBF parameters for one rectangular or square block involves the selection of a set of row (or column) samples on each side of the vertical (or horizontal, respectively) boundary as shown in Figure 2. 3i ,p 2i ,p 1i ,p 0i ,q 0i ,q 1i ,q 2i ,q 3i However, for ease of implementation, it is generally preferable to manage / set DBF parameters per group of samples, e.g., per 4x4 sub-block.

[0055] Therefore, in the following, an embodiment will be described in which DBF parameters for the current block are set for each group of samples in a sub-block of size 4x4. However, the present principle is not limited to determining DBF parameters for 4x4 sub-blocks. Those skilled in the art will directly deduce parameters for other sizes, or even for each single row (or column) from the following example. Next, the block is divided into a set of sub-blocks, and the same DBF parameters (e.g., BS) are derived for all samples of the sub-blocks, except for DBF parameters (e.g., filtering strength) related to sample values ​​in one row (or column).

[0056] 7 shows an example of a triangular logical division (left) and a blending map (right) according to a particular embodiment. For example, in the case of a non-rectangular division, such as a triangle, some samples of one subblock may be predicted using unidirectional prediction, while others may be predicted using bidirectional prediction (a blend of two unidirectional predictions). On the left side of FIG. 7, subblock sb2 indicates a subblock predicted using unidirectional prediction, while subblock sb3 indicates a subblock predicted using bidirectional prediction. In this case, the BS may differ for each sample, since steps 320, 330, and 340 may give different results if the BS selection is performed individually for each sample.

[0057] In the following, we will associate two mixing maps with each sub-block, which contain mixing weights w0(x) and w1(x) associated with the first predictor block P0 and the second predictor block P1, respectively, for each sample (x). The purpose of this map is to facilitate the description of the embodiment, and it may be virtual, i.e., it does not need to be calculated or stored in a memory system. In the case of traditional bi-prediction, the two maps are uniform and equal to 1 / 2. In the case of GBi, the two maps are uniform and, for example, equal to 3 / 8 and 5 / 8, respectively. In the case of MH, for example, w0(x) = w_intra(x) and w1(x) = w_inter(x).

[0058] Several embodiments are described for determining the boundary strength BS used in a general method for deblocking parts of an image. The embodiments can be arranged together according to any combination of several embodiments.

[0059] First embodiment of the deblocking filter A first embodiment comprises a deblocking filter in which the boundary strength is adapted to the number of samples and the relative weights of the samples used in bi-prediction or weighted bi-prediction, which is advantageously well adapted when one sub-block on one side of the boundary uses geometric partitioning or GBi.

[0060] For a given sub-block, process 320 of FIG. 3 is modified as follows: a) If at least one sample within a sub-block is bi-predicted, then the sub-block is considered as bi-predicted for the purpose of BS determination (e.g., sb2 and sb3 for the right-hand mixing map of Figure 7). b) In one variant, if the relative number of samples using bidirectional prediction within a subblock is above a threshold, then the subblock is considered as bidirectionally predicted for the purposes of the BS decision (e.g., sb3 with 14 bidirectionally predicted samples according to the mixing map on the right of Figure 7 is considered as bidirectionally predicted, while sb2 with 3 bidirectionally predicted samples according to the mixing map on the right of Figure 7 is considered as unidirectionally predicted). c) In one variant, the calculation of the number of bidirectionally predicted samples in a subblock excludes samples for which one mixing weight (w0(x) or w1(x)) is below a threshold or level (e.g., th=1 / 4). These samples are considered to be unidirectionally predicted. d) In one variant, let n0 represent the relative number of samples that use reference 0 for prediction and n1 the relative number of samples that use reference 1 for prediction, and if n0 / (n0+n1) and n1 / (n0+n1) are above a threshold, then the sub-block is considered as bi-predicted for the BS decision.

[0061] By way of non-limiting example, in b), c) and d), the threshold or level is 0.

[0062] Advantageously, the thresholds are hard-coded, for example, inside a look-up table indexed by block size and type of division.

[0063] Second embodiment of the deblocking filter A second embodiment comprises a deblocking filter in which the boundary strength is locally adapted to the relative weights of the samples used in combining inter and intra predicted samples, or in combining inter and inter predicted samples, which is advantageously well adapted when one sub-block on either side of the boundary uses MH.

[0064] Considering a sub-block using MH-Inter-Intra: a) Areas of the block where w_intra(x) is above a threshold / level are considered as Intra, e.g. in the case of the MH-Inter-Intra example of Figure 5, the first three upper areas are considered as Intra. b) The area of ​​the block where w_inter(x) exceeds a threshold / level is considered as inter. If inter prediction is bidirectional (or unidirectional), the area is considered as bidirectional (or unidirectional). For example, in the case of the MH-inter-intra example of Figure 5, the last lower area (w_inter(x)=6 / 8) is considered as inter.

[0065] As before, note that in one variation the threshold or level is zero.

[0066] Additionally, in one variant, the thresholds are hard-coded inside a look-up table indexed by the size of the block and the intra direction used.

[0067] Therefore, according to a), if the first prediction mode is the 1 intra prediction mode and the weight of the first predictor (w_intra(x)) is above level, the samples of the first block are considered to use the intra prediction mode to determine the boundary strength. In particular, this applies to any of the intra prediction modes, including directional intra prediction (e.g., vertical intra prediction as shown in FIG. 5) and non-directional modes such as DC or planar. In addition, in the case of planar or DC mode, equal weights are applied to the entire area of ​​the block, resulting in the same intra prediction mode for the entire area of ​​the block. According to the original DBF intent, if the first block P or the second block Q is intra, BS is set to strong (BS=2). Therefore, if the first prediction mode is the 1 intra prediction mode and the weight of the first predictor (w_intra(x)) is above level, the boundary strength is set to strong. In a particular variant corresponding to CIIP (MH-Inter-Intra, where Intra is Planar), BS is set to strong for the block (BS=2).

[0068] In addition, according to b), if the first prediction mode is an inter prediction mode and the weight (w_inter(x)) of the first predictor is greater than level 1, the samples of the first block are considered to use the inter prediction mode to determine the boundary strength. In particular, this applies to any of the inter prediction modes, including unidirectional and bidirectional inter prediction. Thus, if the first prediction mode is an inter bidirectional prediction mode, then the samples of the first block are considered to use the inter bidirectional prediction mode to determine the boundary strength; separately, if the first prediction mode is an inter unidirectional prediction mode, then the samples of the first block are considered to use the inter unidirectional prediction mode to determine the boundary strength. Then, different checks on the difference between the reference index and the motion vector are processed according to the bidirectional or unidirectional inter prediction mode.

[0069] Considering sub-blocks with MH-Inter-Inter, where P0 is bi-predicted and P1 is uni-predicted: c) Areas of the block where w0(x) is above a threshold / level are considered as bi-directionally predicted, while areas of the block where w1(x) is above a threshold are considered as uni-directionally predicted. d) In one variant, if at least P0 or P1 are bi-predicted and {w0(x); w1(x)} is above a threshold, then check 1 and check 2 are modified as follows: For all pairs of values ​​(i;j): ref-i P ≠ref-j Q Is it (Check 1)? ref-i P =ref-j Q For one pair of values ​​(i;j) where: |MVi P -MVj Q |>Is it a threshold? (Check 2) (i;j) is ref-i P >=0 and ref-j Q >=0, etc.

[0070] As before, note that in one variation the threshold or level is zero.

[0071] Advantageously, the thresholds can be hard-coded inside a look-up table indexed by block size and type of division.

[0072] Third embodiment of the deblocking filter A third embodiment comprises a deblocking filter in which the boundary strength is adapted to the weights of the samples used in the prediction, which is advantageously well adapted when one sub-block on one side of the boundary uses generalized bidirectional prediction GBi or BCW.

[0073] Considering the sub-blocks with non-default GBi weights (w0(x); w1(w)) associated with reference 0 and reference 1: a) If w0(x) or w1(x) is below a threshold, then the block is considered as unidirectionally predicted {MV1, ref-1} (or alternatively MV0, ref-0) in steps (320, 330) and only {MV1, ref-1} (or alternatively MV0, ref-0) is used in (340).

[0074] Fourth embodiment of the deblocking filter A fourth embodiment comprises a deblocking filter in which motion vectors are normalized using the POC difference to determine boundary strength. If the first block P and the second block Q have different reference indices, test (320) is inferred as "false" and for (340) the MV values ​​of Q (or P) are rescaled to the same POC as P (or alternatively, Q).

[0075] Fifth embodiment of the deblocking filter A fifth embodiment comprises a deblocking filter in which determining the boundary strength includes a test (an additional condition) as to whether the coding mode of one of the blocks at the boundary is at least one of MH, GBi, and bidirectional prediction.

[0076] 9 shows a flowchart of boundary strength determination in a deblocking filter method according to the fifth embodiment. The BS determination (300) is modified to include an additional condition (315) regarding the coding mode (XX) of the first block P or the second block Q. If the BS determination follows the scheme described in FIG. 3, this additional condition can be placed before / after / between the conditions (310, 320, 330, 340) as shown in one non-limiting example in FIG. 9. According to a non-limiting example, XX is MH and / or GBi and / or bi-prediction. According to another non-limiting example, determining the coding mode (XX) of the first block P or the second block Q conforms to any of the variants described for the first, second, or third embodiment. For example, the coding mode of the block is determined based on the number of samples and the relative weights of the samples used in bi-prediction, and the coding mode of the block is determined based on the relative weights of the samples used in MH. If the coding mode is determined to be intra, BS is set to 2.

[0077] Sixth Embodiment of the Deblocking Filter A sixth embodiment comprises an encoder / decoder in which coding parameters are modified and stored during decoding / reconstruction for later use in a deblocking filter (in determining boundary strength parameters). Figure 10 shows two flowcharts for storing CU parameters used in determining boundary strength (BS) parameters in a deblocking filter method according to a particular embodiment. A method 500 for deblocking the image portions on the left and right of Figure 10 is implemented in the in-loop filtering of the encoder or decoder. The method includes a step 330 of determining BS and a step 400 of applying a filter DBF.

[0078] In one embodiment, depicted on the left side of FIG. 10 , the determination of the BS parameters depends on a subset of CU (or partial CU) parameters (e.g., P, Q mode, reference index, MV value) and is modified according to the previously shown embodiment. In another embodiment, depicted on the right side of FIG. 10 , the determination of the BS parameters 300 is not modified, but some of this subset of CU (or partial CU) parameters are modified (530) after their use to decode (510) and reconstruct (520) the current CU (separately, partial CU) and are stored for use by other processes (e.g., DBF processes). The modification of this subset of CU parameters is a function of other decoded CU parameters 515. This function therefore allows the value of the BS (output of 300) to depend on parameters other than the decoded subset of CU (or partial CU) parameters.

[0079] For example, if the coding mode is MH-inter-intra, and if w_intra(x) is above a threshold, then the coding mode is changed to intra before storing, so that BS is set to strong (BS=2), which corresponds to intra prediction mode, in 300. In this way, the same behavior is obtained as in variant a) of the second embodiment described for MH-inter-intra or CIIP.

[0080] In another example, if the relative number of samples using bidirectional prediction within a subblock exceeds a threshold, then the subblock coding mode is changed to bidirectionally predicted before storage, so that in step 300 the current CU is set as bidirectionally predicted, resulting in the same behavior as described in variant b) of the first embodiment.

[0081] In one variant, these modified CU (or partial CU) parameters stored for later use are used by other CUs (or partial CUs) for processes other than DBF, for example, the modified MV values ​​may be used later for temporal motion prediction (e.g., ATMVP).

[0082] Additional Embodiments and Information This application describes various aspects, including tools, features, embodiments, models, approaches, etc. Many of these aspects are described specifically, and often in a manner that may be considered limiting, at least to illustrate individual features. However, this is for purposes of clarity of description and does not limit the applicability or scope of the aspects. In fact, all of the different aspects can be combined and interchanged to produce further aspects. Furthermore, aspects can also be combined and interchanged with aspects described in previous applications.

[0083] Aspects described and contemplated in this application may be implemented in many different forms. While Figures 11, 12, and 13 below provide some embodiments, other embodiments are contemplated, and the descriptions in Figures 11, 12, and 13 do not limit the breadth of implementations. At least one of the aspects generally relates to video encoding and decoding, and at least one other aspect generally relates to transmitting generated or encoded bitstreams. These and other aspects may be embodied as a method, an apparatus, a computer-readable storage medium having stored thereon instructions for encoding or decoding video data according to any of the above-described methods, and / or a computer-readable storage medium having stored thereon a bitstream generated according to any of the above-described methods.

[0084] In this application, the terms "reconstructed" and "decoded" may be used interchangeably, the terms "pixel" and "sample" may be used interchangeably, and the terms "image," "picture," and "frame" may be used interchangeably. Typically, but not necessarily, the term "reconstructed" is used on the encoder side, while "decoded" is used on the decoder side.

[0085] Various methods are described herein, each of which includes one or more steps or actions for achieving the method described above. Unless a specific order of steps or actions is required for the proper operation of the method, the order and / or use of specific steps and / or actions may be varied or combined.

[0086] Various methods and other aspects described in this application can be used to modify modules, e.g., in-loop filters (165, 265), of video encoder 100 and decoder 200 as shown in Figures 11 and 12. Furthermore, the aspects are not limited to VVC or HEVC, but can be applied, for example, to other standards and recommendations, whether existing or developed in the future, and extensions of any such standards and recommendations (including VVC and HEVC). Unless otherwise indicated or technically excluded, the aspects described in this application can be used individually or in combination.

[0087] In this application, various numerical values ​​are used, for example, a size of 4x4 for the sub-blocks for which DBF parameters are estimated, and the described aspects are not limited to these specific values.

[0088] 11 shows an encoder 100. Variations of this encoder 100 are contemplated, but in the following, for purposes of clarity, encoder 100 will be described without describing all possible variations.

[0089] Before being encoded, a video sequence may undergo encoding pre-processing (101), such as applying a color transformation to the input color picture (e.g., converting from RGB 4:4:4 to YCbCr 4:2:0) or performing a remapping of the input picture components to obtain a signal distribution that is more resilient to compression (e.g., using histogram equalization of one of the color components). Metadata can be associated with the pre-processing and attached to the bitstream.

[0090] In encoder 100, a picture is coded by encoder elements as described below. The picture to be coded is divided (102) and processed, for example, in units of CUs. Each unit is coded, for example, using either intra mode or inter mode. When a unit is coded in intra mode, it performs intra prediction (160). In inter mode, motion estimation (175) and compensation (170) are performed. The encoder determines (105) whether to use intra mode or inter mode to code the unit, and indicates the intra / inter decision, for example, by a prediction mode flag. For example, a prediction residual is calculated by subtracting (110) the prediction block from the original image block.

[0091] The prediction residual is then transformed (125) and quantized (130). The quantized transform coefficients, as well as motion vectors and other syntax elements, are entropy coded (145) to output a bitstream. The encoder can skip the transform and apply quantization directly to the untransformed residual signal. The encoder can bypass both the transform and quantization, i.e., the residual is coded directly without applying a transform or quantization process.

[0092] The encoder decodes the coded blocks to provide references for further prediction. The quantized transform coefficients are dequantized (140) and inverse transformed (150) to decode the prediction residual. The decoded prediction residual and the prediction block are combined (155) to reconstruct an image block. To reduce coding artifacts, an in-loop filter (165) is applied to the reconstructed picture to perform, for example, deblocking / SAO (sample adaptive offset) filtering. The filtered image is stored in a reference picture buffer (180).

[0093] Figure 12 shows a block diagram of a video decoder 200. In the decoder 200, the bitstream is decoded by decoder elements as described below. The video decoder 200 generally performs a decoding pass that is the inverse of the encoding pass as described in Figure 11. The encoder 100 also generally performs video decoding as part of encoding the video data.

[0094] Specifically, the decoder input includes a video bitstream, such as may be generated by video encoder 100. The bitstream is first entropy decoded (230) to obtain transform coefficients, motion vectors, and other coded information. Picture partition information indicates how the picture is partitioned. Thus, the decoder may partition the picture according to the decoded picture partition information (235). The transform coefficients are dequantized (240) and inverse transformed (250) to decode the prediction residual. The decoded prediction residual and the prediction block are combined (255) to reconstruct an image block. The prediction block may be obtained from intra prediction (260) or motion-compensated prediction (i.e., inter prediction) (275) (270). An in-loop filter (265) is applied to the reconstructed image. The filtered image is stored in a reference picture buffer (280).

[0095] The decoded picture may further undergo post-decoding processing (285), such as an inverse color transform (e.g., YCbCr 4:2:0 to RGB 4:4:4) or inverse remapping, which performs the inverse of the remapping process performed in pre-encoding processing (101). Post-decoding processing can use metadata derived in pre-encoding processing and signaled in the bitstream.

[0096] FIG. 13 shows a block diagram of an example system in which various aspects and embodiments may be implemented. System 1000 may be embodied as a device including various components described below and configured to perform one or more of the aspects described herein. Examples of such devices include, but are not limited to, various electronic devices, such as personal computers, laptop computers, smartphones, tablet computers, digital multimedia set-top boxes, digital television receivers, personal video recording systems, connected home appliances, and servers. Elements of system 1000 may be embodied, singly or in combination, in a single integrated circuit (IC), multiple ICs, and / or discrete components. For example, in at least one embodiment, the processing and encoder / decoder elements of system 1000 are distributed across multiple ICs and / or discrete components. In various embodiments, system 1000 is communicatively coupled to one or more other systems or other electronic devices, for example, via a communication bus or through dedicated input and / or output ports. In various embodiments, the system 1000 is configured to implement one or more of the aspects described in this document.

[0097] The system 1000 includes at least one processor 1010, e.g., configured to execute instructions loaded therein to implement various aspects described herein. The processor 1010 may include embedded memory, input / output interfaces, and various other circuitry as known in the art. The system 1000 includes at least one memory 1020 (e.g., a volatile memory device and / or a non-volatile memory device). System 1000 includes storage device 1040, which may include non-volatile and / or volatile memory, including, but not limited to, Electrically Erasable Programmable Read-Only Memory (EEPROM), Read-Only Memory (ROM), Programmable Read-Only Memory (PROM), Random Access Memory (RAM), Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), flash, magnetic disk drives, and / or optical disk drives. Storage device 1040 may include, by way of non-limiting example, an internal storage device, an attached storage device (including removable and non-removable storage devices), and / or a network-accessible storage device.

[0098] System 1000 includes an encoder / decoder module 1030 configured to process data to provide, for example, coded or decoded video, and the encoder / decoder module 1030 may include its own processor and memory. The encoder / decoder module 1030 represents a module that may be included within a device to perform encoding and / or decoding functions. As is known, a device may include one or both of an encoding and a decoding module. Additionally, the encoder / decoder module 1030 may be implemented as a separate element of system 1000 or may be incorporated within processor 1010 as a combination of hardware and software, as is known to those skilled in the art.

[0099] Program code to be loaded onto the processor 1010 or the encoder / decoder 1030 to perform various aspects described herein may be stored in the storage device 1040 and then loaded onto the memory 1020 for execution by the processor 1010. According to various embodiments, one or more of the processor 1010, the memory 1020, the storage device 1040, and the encoder / decoder module 1030 may store one or more of various items during performance of the processes described herein. Such stored items may include, but are not limited to, input video, decoded video or portions of decoded video, bitstreams, matrices, variables, and intermediate or final results from processing of equations, formulas, operations, and operational logic.

[0100] In some embodiments, memory internal to the processor 1010 and / or the encoder / decoder module 1030 is used to store instructions and to provide working memory for processing required during encoding or decoding. However, in other embodiments, memory external to the processing device (e.g., the processing device can be either the processor 1010 or the encoder / decoder module 1030) is used for one or more of these functions. The external memory can be the memory 1020 and / or the storage device 1040, e.g., dynamic volatile memory and / or non-volatile flash memory. In some embodiments, the external non-volatile flash memory is used, for example, to store the television's operating system. In at least one embodiment, a fast external dynamic volatile memory such as RAM is used as working memory for video encoding and decoding operations, such as for MPEG-2 (MPEG stands for Moving Picture Experts Group, MPEG-2 is also referred to as ISO / IEC 13818, 13818-1 is also known as H.222, and 13818-2 is also known as H.262), HEVC (HEVC stands for High Efficiency Video Coding, also known as H.265 and MPEG-H Part 2), or VVC (Versatile Video Coding, an emerging standard being developed by JVET, the Joint Video Experts Team).

[0101] Input to the elements of system 1000 may be provided through various input devices, as indicated in block 1130. Such input devices include, but are not limited to, (i) a radio frequency (RF) section that receives RF signals transmitted, for example, over the air, by a broadcaster, (ii) a component (COMP) input terminal (or set of COMP input terminals), (iii) a Universal Serial Bus (USB) input terminal, and / or (iv) a High Definition Multimedia Interface (HDMI) input terminal. Other examples not shown in FIG. 13 include composite video.

[0102] In various embodiments, the input devices of block 1130 have associated respective input processing elements, as known in the art. For example, the RF section may be associated with elements suitable for (i) selecting a desired frequency (also referred to as selecting a signal or band-limiting a signal to a band of frequencies), (ii) downconverting the selected signal, (iii) band-limiting again to a narrower band of frequencies to select a signal frequency band, which in certain embodiments may be referred to as a channel (for example), (iv) demodulating the downconverted, band-limited signal, (v) performing error correction, and (vi) demultiplexing to select a desired stream of data packets. The RF section of various embodiments includes one or more elements for performing these functions, such as a frequency selector, a signal selector, a band-limiter, a channel selector, a filter, a downconverter, a demodulator, an error corrector, and a demultiplexer. The RF section may include, for example, a tuner for performing various of these functions, including downconverting a received signal to a lower frequency (e.g., an intermediate frequency or a frequency near baseband) or to baseband. In one set-top box embodiment, the RF section and its associated input processing elements perform frequency selection by receiving, filtering, downconverting, and filtering again to a desired frequency band an RF signal transmitted over a wired (e.g., cable) medium. Various embodiments rearrange the order of the above (and other) elements, remove some of these elements, and / or add other elements that perform similar or different functions. Adding elements can include inserting elements between existing elements, such as inserting an amplifier and an analog-to-digital converter. In various embodiments, the RF section includes an antenna.

[0103] Additionally, the USB and / or HDMI terminals may include respective interface processors for connecting system 1000 to other electronic devices through USB and / or HDMI connections. It should be understood that various aspects of the input processing, e.g., Reed-Solomon error correction, may be implemented, for example, within a separate input processing IC or within processor 1010, as desired. Similarly, aspects of the USB or HDMI interface processing may be implemented, for example, within a separate interface IC or within processor 1010, as desired. The demodulated, error corrected, and demultiplexed stream is provided to various processing elements, including processor 1010 and encoder / decoder 1030, which operate in combination with memory and storage elements to process the data stream as desired for presentation on an output device.

[0104] The various elements of system 1000 may be provided within a unitary housing in which the various elements may be interconnected and transmit data therebetween using suitable connection mechanisms, for example, internal buses as known in the art, including inter-IC (I2C) buses, wiring, and printed circuit boards.

[0105] System 1000 includes a communication interface 1050 that enables communication with other devices over a communication channel 1060. Communication interface 1050 may include, but is not limited to, a transceiver configured to transmit and receive data over communication channel 1060. Communication interface 1050 may include, but is not limited to, a modem or a network card, and communication channel 1060 may be implemented in the form of a wired and / or wireless medium, for example.

[0106] In various embodiments, data is streamed or otherwise provided to system 1000 using a wireless network such as a Wi-Fi network, e.g., IEEE 802.11 (IEEE refers to the Institute of Electrical and Electronics Engineers). The Wi-Fi signal in these embodiments is received through communication channel 1060 and communication interface 1050 adapted for Wi-Fi communication. Communication channel 1060 in these embodiments is typically connected to an access point or router that provides access to external networks, including the Internet, to enable streaming applications and other over-the-top communications. Other embodiments provide streamed data to system 1000 using a set-top box that delivers data through an HDMI connection in input block 1130. Still other embodiments provide streamed data to system 1000 using an RF connection in input block 1130. As indicated above, various embodiments provide data in a non-streaming manner. Additionally, various embodiments use wireless networks other than Wi-Fi, such as a cellular network or a Bluetooth network.

[0107] System 1000 can provide output signals to various output devices, including a display 1100, speakers 1110, and other peripheral devices 1120. The display 1100 of various embodiments includes, for example, one or more of a touchscreen display, an organic light-emitting diode (OLED) display, a curved display, and / or a foldable display. The display 1100 can be for a television, a tablet, a laptop, a cell phone, or other device. The display 1100 can also be integrated with other components (e.g., as in a smartphone) or separate (e.g., an external monitor for a laptop). The other peripheral devices 1120, in various example embodiments, include one or more of a stand-alone digital video disc (or digital versatile disc) (DVR, for both terms), a disc player, a stereo system, and / or a lighting system. Various embodiments use one or more peripheral devices 1120 to provide functionality based on the output of system 1000. For example, a disc player performs the function of playing the output of the system 1000 .

[0108] In various embodiments, control signals are communicated between system 1000 and display 1100, speaker 1110, or other peripheral device 1120 using a signaling scheme such as AV.Link, Consumer Electronics Control (CEC), or other communication protocols that enable device-to-device control with or without user intervention. Output devices may be communicatively coupled to system 1000 via dedicated connections through respective interfaces 1070, 1080, and 1090. Alternatively, output devices may be connected to system 1000 using communication channel 1060 via communication interface 1050. Display 1100 and speaker 1110 may be integrated into a single unit with other components of system 1000 within an electronic device such as, for example, a television. In various embodiments, display interface 1070 includes a display driver, such as, for example, a timing controller (T Con) chip.

[0109] For example, if the RF portion of input 1130 is part of a separate set-top box, display 1100 and speakers 1110 can alternatively be separate from one or more of the other components. In various embodiments in which display 1100 and speakers 1110 are external components, the output signal may be provided via a dedicated output connection, including, for example, an HDMI port, a USB port, or a COMP output.

[0110] The embodiments may be implemented by computer software executed by the processor 1010, by hardware, or by a combination of hardware and software. By way of non-limiting example, the embodiments may be implemented by one or more integrated circuits. The memory 1020 may be of any type suitable for the technology environment and may be implemented using any suitable data storage technology, such as, by way of non-limiting example, optical memory devices, magnetic memory devices, semiconductor-based memory devices, fixed memory, and removable memory. The processor 1010 may be of any type suitable for the technology environment and may include, by way of non-limiting example, one or more of a microprocessor, a general-purpose computer, a special-purpose computer, and a processor based on a multi-core architecture.

[0111] Various implementations include decoding. As used herein, "decoding" can encompass all or part of the processes performed on a received encoded sequence, for example, to generate a final output suitable for display. In various embodiments, such processes include processes typically performed by a decoder, such as one or more of entropy decoding, inverse quantization, inverse transform, and differential decoding. In various embodiments, such processes also, or alternatively, include processes performed by decoders of various implementations described herein, such as reconstructing a picture, determining parameters for a deblocking filter, and then filtering the reconstructed picture using the determined deblocking filter parameters.

[0112] As a further example, in one embodiment "decoding" refers only to entropy decoding, in another embodiment "decoding" refers only to differential decoding, and in another embodiment "decoding" refers to a combination of entropy decoding and differential decoding. Whether the expression "decoding process" is intended to refer specifically to a subset of operations or to the broader decoding process as a whole will be clear based on the context of the specific description and will be well understood by one of ordinary skill in the art.

[0113] Various implementations include encoding. In a manner similar to the above description of "decoding," "encoding," as used herein, can encompass all or part of the processes performed on, for example, an input video sequence to generate a coded bitstream. In various embodiments, such processes include processes typically performed by an encoder, such as one or more of: partitioning, differential coding, transforming, quantizing, and entropy coding. In various embodiments, such processes also, or alternatively, include processes performed by encoders in various implementations described herein, such as reconstructing coded pictures, determining parameters for a deblocking filter, and then filtering the reconstructed pictures using the determined deblocking filter parameters.

[0114] As a further example, in one embodiment, "encoding" refers to entropy encoding only, in another embodiment, "encoding" refers to differential encoding only, and in another embodiment, "encoding" refers to a combination of differential and entropy encoding. Whether the expression "encoding process" is intended to refer specifically to a subset of operations or to the broader encoding process as a whole will be clear based on the context of the specific description and will be well understood by one of ordinary skill in the art.

[0115] It should be noted that syntax elements as used herein are, for example, descriptive terms, and therefore do not preclude the use of other syntax element names.

[0116] When a figure is presented as a flow diagram, it should be understood that it also provides a block diagram of the corresponding apparatus. Similarly, when a figure is presented as a block diagram, it should be understood that it also provides a flow diagram of the corresponding method / process.

[0117] Implementations and aspects described herein may be embodied in, for example, a method or process, an apparatus, a software program, a data stream, or a signal. Even if only described in the context of a single implementation (e.g., only described as a method), the described features may also be implemented in other forms (e.g., an apparatus or a program). An apparatus may be embodied in, for example, appropriate hardware, software, and firmware. A method may be embodied in, for example, a processor, which generally refers to a processing device including, by way of example, a computer, a microprocessor, an integrated circuit, or a programmable logic device. Processors also include communication devices, such as, for example, computers, mobile phones, portable / personal digital assistants ("PDAs"), and other devices that facilitate communication of information between end users.

[0118] References to "one embodiment," or "an embodiment," or "one implementation," or "an implementation," as well as other variations thereof, mean that a particular feature, structure, characteristic, etc. described in connection with an embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment," or "in an embodiment," or "in one embodiment," or "in an implementation," as well as any other variations, in various places throughout this application are not necessarily all referring to the same embodiment.

[0119] Additionally, the application may refer to "determining" various information. Determining information may include, for example, one or more of estimating information, calculating information, predicting information, or retrieving information from memory.

[0120] Additionally, the application may refer to "accessing" various information. Accessing information may include, for example, one or more of receiving information, retrieving information (e.g., from a memory), storing information, transferring information, copying information, calculating information, determining information, predicting information, or estimating information.

[0121] Additionally, the application may refer to "receiving" various information. Receiving, like "accessing," is intended to be a broad term. Receiving information may include, for example, one or more of accessing the information or retrieving the information (e.g., from a memory). Furthermore, "receiving" is typically involved in some way in an operation such as, for example, storing information, processing information, transmitting information, transferring information, copying information, erasing information, calculating information, determining information, predicting information, or estimating information.

[0122] For example, in the cases of "A / B," "A and / or B," and "at least one of A and B," it should be understood that the use of any of the following " / ," "and / or," and "at least one of" is intended to encompass the selection of only the first listed alternative (A), or the selection of only the second listed alternative (B), or the selection of both alternatives (A and B). As a further example, in the cases of "A, B, and / or C" and "at least one of A, B, and C," such phraseology is intended to encompass the selection of only the first listed alternative (A), or the selection of only the second listed alternative (B), or the selection of only the third listed alternative (C), or the selection of only the first and second listed alternatives (A and B), or the selection of only the first and third listed alternatives (A and C), or the selection of only the second and third listed alternatives (B and C), or the selection of all three alternatives (A, B, and C). This can be expanded for as many items as listed, as would be apparent to one skilled in this and related arts.

[0123] Also, as used herein, the word "signal" refers, among other things, to instructing a corresponding decoder of something. For example, in a particular embodiment, an encoder signals a particular one of a plurality of parameters for a deblocking filter in de-artifact filtering. Thus, in one embodiment, the same parameters are used at both the encoder and decoder sides. Thus, for example, the encoder can transmit a particular parameter to the decoder (explicit signaling), thereby allowing the decoder to use the same particular parameter. Conversely, if the decoder already has a particular parameter and others, then signaling can be used without transmission simply to allow the decoder to know and select the particular parameter (implicit signaling). By avoiding transmission of any actual function, bit savings are realized in various embodiments. It should be understood that signaling can be achieved in various ways. For example, in various embodiments, one or more syntax elements, flags, etc. are used to signal information to a corresponding decoder. Although the above relates to the verb form of the word "signal," the word "signal" can also be used as a noun herein.

[0124] As will be apparent to those skilled in the art, implementations can generate a variety of signals formatted to carry information that can be, for example, stored or transmitted. The information can include, for example, instructions for performing a method or data generated by one of the implementations described above. For example, a signal can be formatted to carry a bitstream of the above-described embodiments. Such a signal can be formatted, for example, as an electromagnetic wave (e.g., using the radio frequency portion of the spectrum) or as a baseband signal. Formatting can include, for example, encoding a data stream and modulating a carrier wave with the encoded data stream. The information carried by the signal can be, for example, analog or digital information. The signal can be transmitted over a variety of different wired or wireless links, as is well known. The signal can be stored on a processor-readable medium.

[0125] We have described numerous embodiments. Features of these embodiments may be provided alone or in any combination across various claim categories and types. Furthermore, embodiments may include one or more of the following features, devices, or aspects, alone or in any combination across various claim categories and types: Modifying the deblocking filter process applied in the decoder and / or encoder; Enables some advanced deblocking filters in the decoder and / or encoder, Inserting syntax elements into the signaling that allow the decoder to identify the deblocking filter process to use; Selecting a deblocking filter to apply at the decoder based on these syntax elements; Adapting deblocking filter parameters in the decoder and / or encoder; Adapting the boundary strength of the deblocking filter if the blocks at the boundary are a combination of non-square or non-rectangular blocks and / or unequal and / or spatially variable weightings; Adapting the filter strength of the deblocking filter if the blocks at the boundary are a combination of non-square or non-rectangular blocks and / or a combination of unequal and / or spatially variable weightings; Determine a per-sample mixture map for the block that represents the weighted combination used in predicting each sample; Adapting the boundary strength to the number of samples and / or to the sample weights used in bi-prediction; Adapting the boundary strength to the relative weights of the samples used when combining inter and intra predicted samples or when combining inter and inter predicted samples; Adapting the boundary strength to the weights of the samples used in the prediction; Normalizing motion vectors using the POC difference of the reference frame to determine boundary strength; determining the boundary strength includes a test as to whether the prediction mode of one of the blocks at the boundary is at least one of MH, GBi, or bi-prediction; Modifying coding parameters and storing the modified parameters for later use in the deblocking filter (e.g., in determining boundary strength parameters); a bitstream or signal containing one or more of the syntax elements described above or variations thereof; a bitstream or signal containing syntax conveying information generated according to any of the above-described embodiments; Inserting syntax elements into the signaling that allow the decoder to adapt the deblocking filter in a manner corresponding to that used by the encoder; Creating and / or transmitting and / or receiving and / or decoding a bitstream or signal that includes one or more of the syntax elements described above, or variations thereof; Creating and / or transmitting and / or receiving and / or decoding according to any of the embodiments described above; a method, process, apparatus, instruction storage medium, data storage medium, or signal according to any of the above-described embodiments; a TV, set-top box, cell phone, tablet, or other electronic device that performs deblocking filter parameter adaptation according to any of the embodiments described above; a TV, set-top box, cell phone, tablet, or other electronic device that performs deblocking filter parameter adaptation according to any of the above-described embodiments and displays the resulting image (e.g., using a monitor, screen, or other type of display); a TV, set-top box, cell phone, tablet, or other electronic device that selects (e.g., using a tuner) a channel for receiving a signal containing encoded images and performs deblocking filter parameter adaptation according to any of the embodiments described above; A TV, set-top box, cell phone, tablet, or other electronic device that receives (e.g., using an antenna) a wireless signal containing an encoded image and performs deblocking filter parameter adaptation according to any of the embodiments described above.

Claims

1. 1. A method for decoding an image, comprising: decoding a portion of the image portion; - determining at least one boundary between a first block of samples and a second block of samples, said first block and said second block belonging to a portion of said image; determining that the first block has a geometric partitioning mode that performs a weighted combination of a first predictor obtained by a first inter unidirectional prediction and a second predictor obtained by a second inter unidirectional prediction; In response to determining that the first block has the geometric partition mode, storing one of an inter bidirectional prediction mode or an inter unidirectional prediction mode as a prediction mode of the first block according to a weight of a sample of the first predictor; determining a boundary strength of a deblocking filter according to at least one of a prediction mode of the first block and a prediction mode of the second block; filtering samples adjacent to the at least one boundary between the first block and the second block according to a boundary strength of the deblocking filter; A method comprising:

2. The method of claim 1 , wherein if a weight of the sample of the first predictor is greater than zero and less than a maximum weight, the prediction mode of the first block is an inter bidirectional prediction mode.

3. The method of claim 1 , wherein if a weight of the sample of the first predictor is equal to zero or a minimum weight, the prediction mode of the first block is an inter unidirectional prediction mode.

4. The method of claim 1 , wherein the first block of samples and the second block of samples are blocks of size 4×4.

5. 1. A method for encoding an image, comprising: reconstructing the image portion; - determining at least one boundary between a first block of samples and a second block of samples, said first block and said second block belonging to a portion of said image; determining that the first block has a geometric partitioning mode that performs a weighted combination of a first predictor obtained by a first inter unidirectional prediction and a second predictor obtained by a second inter unidirectional prediction; In response to determining that the first block has the geometric partition mode, storing one of an inter bidirectional prediction mode or an inter unidirectional prediction mode as a prediction mode of the first block according to a weight of a sample of the first predictor; determining a boundary strength of a deblocking filter according to at least one of a prediction mode of the first block and a prediction mode of the second block; filtering samples adjacent to the at least one boundary between the first block and the second block according to a boundary strength of the deblocking filter; A method comprising:

6. The method of claim 5 , wherein if a weight of the sample of the first predictor is greater than zero and less than a maximum weight, the prediction mode of the first block is an inter bidirectional prediction mode.

7. The method of claim 5 , wherein if a weight of the sample of the first predictor is equal to zero or a minimum weight, the prediction mode of the first block is an inter unidirectional prediction mode.

8. The method of claim 5 , wherein the first block of samples and the second block of samples are blocks of size 4×4.

9. 1. An apparatus for decoding an image, comprising: decoding a portion of the image portion; - determining at least one boundary between a first block of samples and a second block of samples, said first block and said second block belonging to a portion of said image; determining that the first block has a geometric partitioning mode that performs a weighted combination of a first predictor obtained by a first inter unidirectional prediction and a second predictor obtained by a second inter unidirectional prediction; In response to determining that the first block has the geometric partition mode, storing one of an inter bidirectional prediction mode or an inter unidirectional prediction mode as a prediction mode of the first block according to a weight of a sample of the first predictor; determining a boundary strength of a deblocking filter according to at least one of a prediction mode of the first block and a prediction mode of the second block; filtering samples adjacent to the at least one boundary between the first block and the second block according to a boundary strength of the deblocking filter; 1. An apparatus comprising one or more processors configured to:

10. The apparatus of claim 9 , wherein if a weight of the sample of the first predictor is greater than zero and less than a maximum weight, the prediction mode of the first block is an inter bidirectional prediction mode.

11. The apparatus of claim 9 , wherein if a weight of the sample of the first predictor is equal to zero or a minimum weight, the prediction mode of the first block is an inter unidirectional prediction mode.

12. The apparatus of claim 9 , wherein the first block of samples and the second block of samples are blocks of size 4×4.

13. 1. An apparatus for encoding an image, comprising: reconstructing the image portion; - determining at least one boundary between a first block of samples and a second block of samples, said first block and said second block belonging to a portion of said image; determining that the first block has a geometric partitioning mode that performs a weighted combination of a first predictor obtained by a first inter unidirectional prediction and a second predictor obtained by a second inter unidirectional prediction; In response to determining that the first block has the geometric partition mode, storing one of an inter bidirectional prediction mode or an inter unidirectional prediction mode as a prediction mode of the first block according to a weight of a sample of the first predictor; determining a boundary strength of a deblocking filter according to at least one of a prediction mode of the first block and a prediction mode of the second block; filtering samples adjacent to the at least one boundary between the first block and the second block according to a boundary strength of the deblocking filter; 1. An apparatus comprising one or more processors configured to:

14. The apparatus of claim 13 , wherein if a weight of the sample of the first predictor is greater than zero and less than a maximum weight, the prediction mode of the first block is an inter bidirectional prediction mode.

15. The apparatus of claim 13 , wherein if a weight of the sample of the first predictor is equal to zero or a minimum weight, the prediction mode of the first block is an inter unidirectional prediction mode.

16. The apparatus of claim 13 , wherein the first block of samples and the second block of samples are blocks of size 4×4.

17. A computer readable medium containing software code instructions for performing the method of any one of claims 1 to 8 when the software code instructions are executed by one or more processors.

Images