Abstract: Techniques are described to unify the motion vectors of sub-blocks of an affine block and the motion vector information that is stored and used as predictors for determining motion vectors for subsequent blocks. A video coder may determine that the motion vector for a sub-block is the same as the motion vector information that is used to determine motion vectors for subsequent blocks.

Abstract: Coding a motion vector difference (MVD) during an inter-prediction process. Example techniques may include determining a particular coding and/or signaling method for an MVD from among two or more MVD coding and/or signaling techniques. A video coder (e.g., a video encoder and/or a video decoder) may determine a particular MVD coding and/or signaling technique based on characteristics of video data or coding methods, including MV precision, Picture Order Count (POC) difference, or any other already coded/decoded information of a block of video data.

Abstract: A method of encoding and decoding video data, including coding a first syntax element that specifies a value used to derive a maximum number of intra block copy merging candidates, deriving the maximum number of intra block copy merging candidates based on the value of the first sytnax element, and coding a first block of video data using intra block copy mode according to the maximum number of intra block copy merging candidates.

Abstract: Embodiments include methods and apparatus for encoding and decoding video data. In particular, embodiments include methods and apparatus for encoding and decoding video using a combined inter/intra prediction mode. In one such embodiment, the inter prediction is performed using a equal weighted bi-prediction mode determined using a merge mode that would otherwise indicate a non-equal weighted bi-prediction.

Abstract: Techniques are described for history-based candidate list operations in video coding for determining motion information for a current block. In one example, a device for decoding video data includes a memory configured to store a history-based candidate list and a video decoder. The video decoder is configured to construct the history-based candidate list by storing, in the memory, motion information of reconstructed blocks into the history-based candidate list as candidates of the history-based candidate list, identify a subset of candidates of the history-based candidate list, generate a candidate list based on the identified subset of candidates of the history-based candidate list, and reconstruct a current block based on the generated candidate list.

Abstract: Provided are systems, methods, and computer-readable medium for encoding and decoding video data. In various examples, a coding device can include multiple luma QP and chroma QP relationship tables. In performing quantization or inverse quantization one video data being encoded or decoded, respectively, the coding device can select a table. The table can be selected based on, for example, a slice type, a prediction mode, and/or a luminance value, among other factors. The coding device can then use the luma QP value to look up a chroma QP value from the table. The luma QP and chroma QP values can then be used in quantization or inverse quantization.

Abstract: This disclosure describes gradient-based prediction refinement. A video coder (e.g., video encoder or video decoder) determines one or more prediction blocks for inter-predicting a current block (e.g., based on one or more motion vectors for the current block). In gradient-based prediction refinement, the video coder modifies one or more samples of the prediction block based on various factors such as displacement in a horizontal direction, the horizontal gradient, a displacement in the vertical direction, and a vertical gradient. This disclosure provides for gradient-based prediction refinement where a precision level of the displacement (e.g., at least one of the horizontal or vertical displacement) is unified (e.g., the same) for different prediction modes (e.g., including an affine mode and a bi-directional optical flow (BDOF) mode).

Abstract: An example device for decoding video data includes a memory configured to store the video data and one or more processors implemented in circuitry and coupled to the memory. The one or more processors are configured to determine a first distance index associated with a first geometric partition mode (GEO) angle for a first prediction unit (PU) of the video data to be 4. The one or more processors are configured to determine a first displacement value based on the first distance index, the first displacement value being indicative of a distance from a center of the first PU to a GEO split. The one or more processors are configured to decode the first PU based on the first GEO angle and the first displacement value. The first displacement value is half of a displacement value associated with a distance index of 2.

Abstract: An example device includes a memory and processing circuitry in communication with the memory. The processing circuitry of a device is configured to form a most probable mode (MPM) candidate list for a chroma block of the video data stored to the memory, such that the MPM candidate list includes one or more derived modes (DMs) associated with a luma block of the video data associated with the chroma block, and a plurality of luma prediction modes that can be used for coding luminance components of the video data. The processing circuitry is further configured to select a mode from the MPM candidate list, and to code the chroma block according to the mode selected from the MPM candidate list.

Abstract: A method of decoding video data includes constructing, by a video decoder implemented in processing circuitry, a candidate list of motion vector information for a portion of a current frame. The method includes receiving, by the video decoder, signaling information indicating starting motion vector information of the candidate list of motion vector information, the starting motion vector information indicating an initial position in a reference frame. The method includes refining, by the video decoder, based on one or more of bilateral matching or template matching, the starting motion vector information to determine refined motion vector information indicating a refined position in the reference frame that is within a search range from the initial position. The method includes generating, by the video decoder, a predictive block based on the refined motion vector information and decoding, by the video decoder, the current frame based on the predictive block.

Abstract: A video decoder can be configured to determine that a first block of the video data is encoded in a cross component linear model (CCLM) mode; determine that the first block has a first bit depth; determine that a second block of the video data is encoded in the CCLM mode; determine that the second block has a second bit depth that is different than the first bit depth; and decode the first block and the second block in the CCLM mode using a fixed bit depth, wherein the fixed bit depth is different than at least one of the first bit depth or the second bit depth.

Abstract: Systems and techniques for performing illumination compensation in processing video data include deriving one or more illumination compensation parameters for a block of a picture based on one or more tools which may be used for inter-prediction of the block. Illumination compensation can be selectively applied for the block based on whether bi-directional prediction is to be applied for the inter-prediction of the block. In some cases if it is determined that bi-directional prediction is to be applied for inter-prediction of the block, illumination compensation may be avoided for the block.

Abstract: A device for decoding video data includes a memory configured to store video data and one or more processors implemented in circuitry and configured to store sets of adaptive loop filter (ALF) parameters in a one-dimensional array in the memory, the one-dimensional array having a predefined size of N memory elements, N being a positive integer value, wherein the one or more processors are configured to store, in one or more of the memory elements of the array, both corresponding ALF parameters and a temporal layer identifier (ID) value indicating a temporal layer from which the corresponding ALF parameters are to be estimated; decode one or more blocks of the video data; and filter the one or more blocks using the ALF parameters of the one-dimensional array. The device may further encode the one or more blocks prior to decoding the one or more blocks.

Abstract: An example method includes obtaining values of control point motion vectors (CPMVs) for a current block of video data selected for coding using affine mode; determining whether a memory bandwidth needed for accessing samples of a plurality of reference blocks derived based on the values of the CPMVs satisfies a bandwidth threshold; selectively modifying, based on whether the determined memory bandwidth satisfies the bandwidth threshold, a motion compensation method used to predict samples of the current block of video data; and predicting, using the selectively modified motion compensation method, the samples of the current block of video data from the samples of the plurality of reference blocks.

Abstract: A method of decoding video data includes receiving encoded data for a current block of the video data, the current block comprising one or more escape mode encoded samples and decoding, from the encoded data, a value indicating that the current block includes the one or more escape mode encoded samples. The method further includes, in response to determining that the value indicates that the current block includes the one or more escape mode encoded samples and that a current tree type for the current block is not dual tree chroma, decoding an absolute value for a luma delta quantization parameter for the current block and a sign for the luma delta quantization parameter. The method further includes reconstructing the current block based on the absolute value for the luma delta quantization parameter for the current block and the sign for the luma delta quantization parameter.

Abstract: Systems, methods, and computer-readable storage media for restricting block sizes for illumination compensation are described. An example method can include obtaining a block of a picture of video data; determining a size of the block; determining whether the size of the block is equal to or less than a first block size associated with a block size restriction that restricts bi-directional inter-prediction for blocks having a respective size that is equal to or less than the first block size associated with the block size restriction or whether the size of the block is greater than a second block size associated with a video coding pipeline structure; and disabling illumination compensation for the block based on a determination that the size of the block is equal to or less than the first block size or greater than the second block size.

Abstract: A video coder is configured to form, in a symmetric motion vector difference mode, a List 0 (L0) base vector using a L0 Advanced Motion Vector Prediction (AMVP) candidate list and a List 1 (L1) base vector using a L1 AMVP candidate list; determine a refined L0 motion vector and a refined L1 motion vector by performing a decoder-side motion vector refinement process that refines the L0 base vector and the L1 base vector; and use the refined L0 motion vector and the refined L1 motion vector to determine a prediction block for a current block of a current picture of the video data.

Abstract: A video coder may determine a motion vector of a non-adjacent block of a current picture of the video data. The non-adjacent block is non-adjacent to a current block of the current picture. Furthermore, the video coder determines, based on the motion vector of the non-adjacent block, a motion vector predictor (MVP) for the current block. The video coder may determine a motion vector of the current block. The video coder may also determine a predictive block based on the motion vector of the current block.

Abstract: Improved systems and methods related to decoder-side motion vector derivation (DMVD), for example, in applying one or more constraints to motion information, such as a MV derived by DMVD, and/or a MV difference between an initial MV and an MV derived by DMVD. These techniques may be applied to any of the existing video codecs, such as HEVC (High Efficiency Video Coding), and/or may be an efficient coding tool in any future video coding standards. In one example, the block size used for DMVD can be restricted. In another example, FRUC bilateral matching can be simplified by not searching outside reference blocks indicated by the original motion vector.

Abstract: A method of coding video data, including constructing a history-based motion vector prediction (HMVP) candidate history table that includes motion vector information of previously coded blocks that extend beyond adjacent neighboring blocks of a current block, constructing a motion vector predictor list, and adding one or more HMVP candidates from the HMVP candidate history table to the motion vector predictor list. Adding the one or more HMVP candidates from the HMVP candidate history table comprises comparing a first HMVP candidate in the HMVP candidate history table to two entries in the motion vector predictor list and no other entries, and adding the first HMVP candidate to the motion vector predictor list when the first HMVP candidate is different than both of the two entries in the motion vector predictor list. The method also includes coding the current block of video data using the motion vector predictor list.