Qualcomm Incorporated

Other

Feng Zou

Marta Karczewicz

Rajan Laxman Joshi

Wei Pu

Vadim Seregin

Joel Sole Rojals

Jianle Chen

Xiang Yang Li

Hsiao-Chiang Chuang

Wei-Jung Chien

Yi-Wen Chen

Li Feng Zhang

Liwei Guo

Xin Zhao

Xiang Li

Simon J Gibbs

Cheng-Teh Hsieh

Chao Pang

Rodger J Lea

An example device includes a memory to store the video data, and processing circuitry in communication with the memory. The processing circuitry is configured to compare a value of a dimension of a current block of the stored video data to a value of a corresponding dimension of a neighboring block of the current block to obtain a relative dimension value. The processing circuitry is further configured to determine, based on the relative dimension value, that the current block is to be partitioned according to a prediction tree (PT) portion of a multi-type tree-based partitioning scheme. The PT portion comprises partitioning according to one of a binary tree structure or a center-side triple tree structure. The processing circuitry is further configured to partition, based on the determination, the current block according to the PT portion, to form a plurality of sub-blocks.

Tree-type coding for video coding

An example method includes determining, without receiving explicit signaling, whether motion compensation for a current block of a current picture of video data is to be performed using a four-parameter affine motion model (AMM) defined by two motion vectors (MVs) or using a six-parameter AMM defined by three MVs; deriving values of predictors for MVs of the AMM of the current block; decoding a representation of differences between the values of the MVs of the AMM for the current block and the values of the predictors; determining the values of the MVs of the AMM for the current block from the values of the predictors and the decoded differences; determining, based on the determined values of the MVs of the AMM for the current block of video data, a predictor block of video data; and reconstructing the current block based on the predictor block.

Affine motion prediction for video coding

Methods incorporating extensions to copy-above mode for palette mode coding are disclosed. In one aspect, the method includes coding a current pixel of a current block of video data in copy-previous mode via coding a previous line index. The coding of the current pixel in copy-previous mode further including identifying a number of candidate values for the previous line index, identifying a number of escape pixels in a column of pixels above the current pixel in the current block, and reducing a number of candidate values of the previous line index by the number of identified escape pixels.

Methods incorporating extensions to copy-above mode for palette mode coding

An example device for decoding video data includes a video decoder configured to decode one or more syntax elements at a region-tree level of a region-tree of a tree data structure for a coding tree block (CTB) of video data, the region-tree having one or more region-tree nodes including region-tree leaf and non-leaf nodes, each of the region-tree non-leaf nodes having at least four child region-tree nodes, decode one or more syntax elements at a prediction-tree level for each of the region-tree leaf nodes of one or more prediction trees of the tree data structure for the CTB, the prediction trees each having one or more prediction-tree leaf and non-leaf nodes, each of the prediction-tree non-leaf nodes having at least two child prediction-tree nodes, each of the prediction leaf nodes defining respective coding units (CUs), and decode video data for each of the CUs.

Coding video data using a two-level multi-type-tree framework

The method includes receiving video blocks that are each associated with a table having entries specifying pixel values used in the blocks. The method further includes dividing the blocks into sub-blocks each having an array of pixels. The method also includes selecting a sub-block scanning order that specifies an order in which the plurality of sub-blocks are to be encoded and a pixel scanning order that specifies an order in which the pixels of each sub-block are to be encoded. The scanning order and the pixel scanning order are selected based at least in part upon pixel value distributions and a bit rate for encoding the block according to the scanning or pixel scanning order, respectively. The blocks are then encoded using the selected scanning order and pixel scanning order and the index values in the table.

Methods and apparatus for encoding video data using block palettes and sub-block and pixel scanning orders

An example method of coding video data includes coding, from a coded video bitstream, a syntax element that indicates whether a transpose process is applied to palette indices of a palette for a current block of video data; decoding, from the coded video bitstream and at a position in the coded video bitstream that is after the syntax element that indicates whether the transpose process is applied to palette indices of the palette for the current block of video data, one or more syntax elements related to delta quantization parameter (QP) and/or chroma QP offsets for the current block of video data; and decoding the current block of video data based on the palette for the current block of video data and the one or more syntax elements related to delta QP and/or chroma QP offsets for the current block of video data.

Grouping palette bypass bins for video coding

An example method includes obtaining, for a current block of video data, values of motion vectors (MVs) of an affine motion model of a neighboring block of video data; deriving, from the values of the MVs of the affine motion model of the neighboring block, values of predictors for MVs of an affine motion model of the current block; decoding, from a video bitstream, a representation of differences between the values of the MVs of the affine motion model for the current block and the values of the predictors; determining the values of the MVs of the affine motion model for the current block from the values of the predictors and the decoded differences; determining, based on the determined values of the MVs of the affine motion model for the current block, a predictor block of video data; and reconstructing the current block based on the predictor block.

A device for decoding video data is configured to determine, based on first entropy encoded data in the bitstream, a set of run-related syntax element groups for a current block of a current picture of the video data; determine, based on second entropy encoded data the bitstream, a set of palette index syntax elements for the current block, the first entropy encoded data occurring in the bitstream before the second entropy encoded data, wherein: each respective run-related syntax element group of the set of run-related syntax element groups indicates a respective type of a respective run of identical palette mode type indicators and a respective length of the respective run and each respective palette index syntax element of the set of palette index syntax elements indicates an entry in a palette comprising a set of sample values; and reconstruct, based on the sample values in the palette, the current block.

Grouping palette index at the end and index coding using palette size and run value

In one example, a device includes a memory configured to store video data and a video decoder configured to decode an exponential Golomb codeword representative of at least a portion of a value for an escape pixel of a palette-mode coded block of video data, the video decoder is configured to decode the exponential Golomb codeword using exponential Golomb with parameter 3 decoding, and decode the block using the value for the escape pixel.

Coding escape pixels for palette coding

In palette-based coding, a video coder may form a so-called 'palette' as a table of colors representing the video data of a given block. The video coder may code index values for one or more pixels values of a current block of video data, where the index values indicate entries in the palette that represent the pixel values of the current block. A method includes determining a palette for a block of video data, identifying escape pixel(s) not associated with any palette entries, identifying a single quantization parameter (QP) value for all escape pixels of the block for a given color channel using a QP value for non-palette based coding of transform coefficients, dequantizing each escape pixel using the identified QP value, and determining pixel values of the block using the dequantized escape pixels and index values for any pixel(s) associated with any palette entries.

Color index coding for palette-based video coding

Techniques for encoding a binary prediction vector for predicting a palette for palette-based video coding is described. In one example, a method of decoding video comprises receiving an encoded binary prediction vector for a current block of video data, decoding the encoded binary prediction vector using a run-length decoding technique, generating a palette for the current block of video data based on the binary prediction vector, the binary prediction vector comprising entries indicating whether or not previously-used palette entries are reused for the palette for the current block of video data, and decoding the current block of video data using the palette.

Palette predictor signaling with run length code for video coding

An example method of decoding video data includes determining a palette for decoding a block, the palette including entries each having a respective palette index, determining a reference run of palette indices for first pixels of the block, and determining a current run of palette indices for second pixels of the block, based on the reference run. Determining the second plurality of palette indices includes locating a reference index of the reference run, the reference index being spaced at least one line from an initial index of the current run, determining a run length of the reference run, a final index of the reference run being separated from the initial index of the current run by at least one index, copying the palette indices of the reference run as the current run of palette indices, and decoding pixels of the copied current run using the palette.

Copy from previous rows for palette mode coding

A method of decoding video data, the method comprising receiving a run-length sequence indicative of a binary vector, the binary vector comprising indications of locations of escape samples in a block of video data encoded using a palette-based coding mode, decoding the run-length sequence to obtain the binary vector, and decoding the block of video data using the binary vector. The method of claimmay further comprise receiving palette entries for the block of video data receiving one or more escape samples, and receiving a plurality of flags indicating the palette mode for each respective pixel in the block of video data.

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San Diego, CA, United States of America

Feng Zou