Abstract: An example method includes determining a respective variance value for pixels of each respective sub-block of at least four sub-blocks of a current block of video data of a particular block size; determining an average of the determined variance values for the at least four sub-blocks; determining a maximum difference value for the current block based on the average and the variance values for the at least four sub-blocks; determining whether pixels of the current block are homogeneous based on whether the maximum difference value for the current block satisfies a threshold difference value; and in response to determining that the pixels of the current block are homogeneous, selectively including block sizes that are greater than or equal to a threshold block size in a sub-set of block sizes to evaluate for use when intra encoding the pixels of the current block.

Abstract: In general, the disclosure describes a video coding device (e.g., a video encoder or a video decoder) configured to perform various transformations on video data. The video coding device applies a primary transform to a block of the video data, the primary transform having a first size, and the sub-block being at least a portion of the block. The video coding device determines whether application of a secondary transform, having a second size, to a sub-block of the block is allowed. Application of the secondary transform is disallowed when the first size is equal to the second size. Based on the application of the secondary transform being allowed, the video coding device applies the secondary transform to the sub-block. Application of the primary transform and the secondary transform construct a residual block in a pixel domain.

Abstract: In one example, a device for accessing image data includes a memory configured to store image data, the memory comprising a first region and a second region; and one or more processing units configured to code most significant bits (MSBs) of a plurality of residuals of samples of a block of an image, each of the residuals representing a respective difference value between a respective raw sample value and a respective predicted value for the respective raw sample value, access the coded MSBs in the first region of the memory, and access least significant bits (LSBs) of the plurality of residuals of the samples in the second region of the memory.

Abstract: A method for decoding video data provided in a bitstream, where the bitstream includes a coding unit (CU) coded in palette mode, includes: parsing a palette associated with the CU provided in the bitstream; parsing one or more run lengths provided in the bitstream that are associated with the CU; parsing one or more index values provided in the bitstream that associated with the CU; and parsing one or more escape pixel values provided in the bitstream that are associated with the CU. The escape pixel values may be parsed from consecutive positions in the bitstream, the consecutive positions being in the bitstream after all of the run lengths and the index values associated with the CU. The method may further include decoding the CU based on the parsed palette, parsed run lengths, parsed index values, and parsed escape values.

Abstract: Techniques are described for determining boundary strength value for an intra-block copy (IBC)-coded block and for selective storage of unfiltered pixel values of a region of a picture based on whether the region will be used as reference for IBC coding.

Abstract: An example method includes determining a respective variance value for pixels of each respective sub-block of at least four sub-blocks of a current block of video data of a particular block size; determining an average of the determined variance values for the at least four sub-blocks; determining a maximum difference value for the current block based on the average and the variance values for the at least four sub-blocks; determining whether pixels of the current block are homogeneous based on whether the maximum difference value for the current block satisfies a threshold difference value; and in response to determining that the pixels of the current block are homogeneous, selectively including block sizes that are greater than or equal to a threshold block size in a sub-set of block sizes to evaluate for use when intra encoding the pixels of the current block.

Abstract: Provided are techniques for low complexity video coding. For example, a video coder may be configured to calculate a first sum of absolute difference (SAD) value between a CU block and a corresponding block in a reference frame for the largest coding unit (LCU). The video coder may define conditions (e.g., background and/or homogeneous conditions) for the branching based at least in part on the first SAD value. The video coder may also determine the branching based on detecting the background or homogeneous condition, the branching including a first branch corresponding to both a first CU size of the CU block and a second CU size of a sub-block of the CU block. The video coder may then set the first branch to correspond to the first CU size, if the first CU size or the second CU size satisfies the background condition.

Abstract: Provided are techniques for low complexity video coding. For example, a video coder may be configured to calculate a first sum of absolute difference (SAD) value between a coding unit (CU) block and a first corresponding block in a reference frame, and define branching conditions for branching of CU sizes based on the first SAD value, the branching conditions including a background condition and/or a homogeneous condition. The video coder may be configured to detect the background condition if the first SAD value of the CU block is less than a first threshold background value, and detect the homogeneous condition if a second SAD value of a sub-block of the CU block is between upper and lower homogeneous threshold values based on the first SAD value. The branching of the CU sizes may be based on detecting the background or homogeneous conditions.

Abstract: In an example, a method of transforming video data comprises determining, based on variable operational code, a plurality of control parameters for transforming the video data in a transform domain, wherein the operational code maps each of the plurality of control parameters to respective operational code fields, and performing transformation of the video data based on the determined control parameters.

Abstract: Systems and methods are provided for video encoding and decoding using intra-block copy mode when constrained intra-prediction is enabled. In various implementations, a video encoding device can determine a current coding unit for a picture from a plurality of pictures. The video encoding device can further determine that constrained intra-prediction mode is enabled. The video encoding device can further encode the current coding unit using one or more reference samples. The one or more reference samples are determined based on whether a reference sample has been predicted using intra-block copy mode prediction without using any inter-predicted samples. When the reference sample is predicted using intra-block copy mode without using any inter-predicted samples, the reference sample is available for predicting the current coding unit.

Abstract: A device for decoding video data adds motion information of a neighboring block of a current block to a merge candidate list, wherein the motion information comprises a motion vector of the neighboring block, and wherein the motion vector refers to the current picture; receives an index indicating a merge candidate from the merge candidate list; and in response to the index indicating the merge candidate corresponding to the motion information of the neighboring block, predicts the current block using a lower precision motion vector that represents a rounded version of the motion vector of the neighboring block.

Abstract: An apparatus configured to decode video data that comprises a memory configured to store the video data; and one or more processors. The one or more processors are configured to: receive a bitstream that is constrained such that escape values used in a palette mode for decoding the video data are no greater than a maximum value, wherein the bitstream includes information for determining at least one escape value representing a sample in a block of the video data to be decoded; and reconstruct the sample in the block of the video data using the information for determining the at least one escape value.

Abstract: In an example, a method of transforming video data in video coding includes applying a first stage of a two-dimensional transform to a block of video data values to generate a block of first stage results, and applying a second stage of the two-dimensional transform to the block of first stage results without reordering the first stage results to generate a block of second stage results.

Abstract: A device for decoding video data includes a memory configured to store the video data and one or more processors configured to receive a slice of the video data, parse an intra block copy (IBC) syntax element to determine that an IBC mode is enabled for the slice, parse a slice type syntax element associated with the slice to determine the slice is an I slice, and decode the slice as an I slice by decoding all blocks of the slice using intra prediction coding modes.

Abstract: Systems and methods for interleaving video sub-blocks in video coding are described herein. In one aspect, an apparatus includes a memory and a video coder. The memory stores a first video block and a second video block. The first video block and the second video block include sub-blocks. The video coder processes a first sub-block of the first video block according to a first process and a second process, and processes a second sub-block of the first video block according to the first process and the second process after processing the first sub-block of the first video block according to the first process and the second process. Further, the video coder processes a first sub-block of the second video block according to the first process before processing the second sub-block of the first video block according to the first process.

Abstract: A device for encoding or decoding video data may clip first residual data based on a bit depth of the first residual data. The device may generate second residual data at least in part by applying an inverse Adaptive Color Transform (TACT) to the first residual data. Furthermore, the device may reconstruct, based on the second residual data, a coding block of a coding unit (CU) of the video data.

Abstract: Provided are techniques for low complexity video coding. For example, a video coder may be configured to calculate a first sum of absolute difference (SAD) value between a CU block and a corresponding block in a reference frame for the largest coding unit (LCU). The video coder may define conditions (e.g., background and/or homogeneous conditions) for the branching based at least in part on the first SAD value. The video coder may also determine the branching based on detecting the background or homogeneous condition, the branching including a first branch corresponding to both a first CU size of the CU block and a second CU size of a sub-block of the CU block. The video coder may then set the first branch to correspond to the first CU size, if the first CU size or the second CU size satisfies the background condition.

Abstract: Provided are techniques for low complexity video coding. For example, a video coder may be configured to calculate a first sum of absolute difference (SAD) value between a coding unit (CU) block and a first corresponding block in a reference frame, and define branching conditions for branching of CU sizes based on the first SAD value, the branching conditions including a background condition and/or a homogeneous condition. The video coder may be configured to detect the background condition if the first SAD value of the CU block is less than a first threshold background value, and detect the homogeneous condition if a second SAD value of a sub-block of the CU block is between upper and lower homogeneous threshold values based on the first SAD value. The branching of the CU sizes may be based on detecting the background or homogeneous conditions.

Abstract: Techniques are described for determining boundary strength value for an intra-block copy (IBC)-coded block and for selective storage of unfiltered pixel values of a region of a picture based on whether the region will be used as reference for IBC coding.

Abstract: In an example, a method of processing video data includes determining an input parameter for a truncated binary code that represents a palette index for a pixel of a block of video data based on a number of indices in a palette for the block. The method also includes coding a prefix of the truncated binary code, and determining a palette coding mode for the pixel from a first palette coding mode and a second palette coding mode based only on the prefix of the truncated binary code.