Qualcomm Incorporated

Nan Hu

Marta Karczewicz

Vadim Seregin

Wei-Jung Chien

Muhammed Zeyd Coban

Vijayaraghavan Thirumalai

Xin Zhao

Yong He

Hilmi Enes Egilmez

Li Feng Zhang

Cheng-Teh Hsieh

Xiang Yang Li

Amir Said

Jie Dong

Hsiao-Chiang Chuang

Venkata Meher Satchit Anand Kotra

Jianle Chen

Rajarshi Gupta

Adarsh Krishnan Ramasubramonian

Saumitra Mohan Das

Anand Meher Kotra

Yi-Wen Chen

Han Huang

Hui Chao

Yu-Chen Sun

Hongtao Wang

Yao-Jen Chang

Yan Zhang

Akshay Gadde

Keming Cao

Systems, methods, and media are provided for loop filtering across raster scan slices. One example includes obtaining the video data comprising one or more pictures and a first block of a picture having a pixel subject to filtering. A second block is determined to be located in the first slice in a particular relation to the second block. A third block that includes pixels for filtering the pixel is determined to be in a second slice at a diagonal corner of the first block, with filtering across slice boundaries disabled. First one or more pixels of the second block are identified as available for performing loop filtering of the pixel and second one or more pixels of the third block identified as unavailable for performing the loop filtering of the pixel of the first block. The first one or more pixels and the second one or more pixels are padded.

Reusing adaptive loop filter (ALF) sub-picture boundary processing for raster-scan slice boundaries

An example device for decoding video data includes a memory configured to store video data; and one or more processors implemented in circuitry and configured to: decode a current block of the video data to form a decoded block; determine that a current sample of the decoded block neighbors a sample along a virtual boundary in the decoded block and neighbors one or more samples that are not along any virtual boundary in the decoded block; compute band information for cross component sample adaptive offset (CCSAO) for the current sample using at least one of the one or more samples that are not along any virtual boundary in the decoded block and without using the sample along the virtual boundary; and perform CCSAO on the current sample using the band information.

Virtual boundary processing for CCSAO, bilateral filter and adaptive loop filter for video coding

An example device for decoding video data includes a memory configured to store video data; and a processing system including one or more processors implemented in circuitry, the processing system being configured to: determine that a previously coded block of video data was coded using uni-prediction mode for which a bi-prediction syntax element is not assigned a value; determine that a current block of the video data is to be coded using a bi-prediction mode and that motion information of the current block is to be predicted from the previously coded block, including from the bi-prediction syntax element of the previously coded block; and in response to the bi-prediction syntax element of the previously coded block not having an assigned value, decode the current block using a substitute value for the bi-prediction syntax element.

Using substitute motion information when coding video data

A device for decoding video data determines a pre-filtered reconstructed block of video data; applies one or more of a deblocking filter or a sample adaptive offset filter to the pre-filtered reconstructed block to determine a filtered reconstructed block; applies an adaptive loop filter (ALF) to the filtered reconstructed block to determine a final filtered reconstructed block, wherein to apply the ALF to the filtered reconstructed block, the device is further configured to determine a difference value based on a difference between a value of a current sample of the filtered reconstructed block and a value of a pre-filtered neighboring sample; apply a filter to the difference value to determine a sample modification value; and determine a final filtered sample value based on the sample modification value.

Adaptive loop filter with samples before deblocking filter and samples before sample adaptive offsets

A video decoder is configured to determine, for a current block of video data, a classifier from a plurality of available classifiers for the current block, wherein each classifier of the plurality of available classifiers defines a process for calculating a class index; determine a class index based on the classifier and one or more sample values of the current block; select a filter from a set of filters based on the class index; and apply the filter to the current block.

Signaled adaptive loop filter with multiple classifiers in video coding

A method of encoding or decoding video data comprises: for each respective intra prediction mode of a plurality of intra prediction modes in a most-probable mode (MPM) list: generating, based on reference samples for a template region and using the respective intra prediction mode, prediction samples for the template region; and determining a cost for the respective intra prediction mode; determining a first intra prediction mode and a second intra prediction mode in the MPM list having lowest costs; determining a preliminary prediction block for the first intra prediction mode and a preliminary prediction block for the second intra prediction mode; generating a prediction block based on a fusion of the preliminary prediction blocks weighted according to a weight for the first intra prediction mode and a weight for the second intra prediction mode.

Derived intra prediction modes and most probable modes in video coding

A video encoder may be configured to encode multiple adaptive loop filter sets in an adaptation parameter set associated with the video data. A video decoder may receive the multiple adaptive loop filter sets in the adaptation parameter set associated with video data, determine one or more adaptive loop filters from the multiple adaptive loop filter sets, and apply the determined one or more adaptive loop filters to the video data.

Multiple adaptive loop filter sets

A video encoder or video decoder are configured to reconstruct the video data to generate reconstructed video data. The video encoder or video decoder may further perform a plurality of loop filter operations on the reconstructed video data in parallel, wherein the plurality of loop filter operations includes a first filter operation that is not a bilateral filter operation or a sample adaptive offset (SAO) filter operation, and perform a joint clipping operation on a first output of the first filter and a second output of a second loop filter operation of the plurality of loop filter operations. The first filter operation may be a cross-component sample adaptive offset (CCSAO) filter operation.

Joint clipping operating for filters for video coding

An example method includes decoding, via a first syntax level of a video bitstream, a first deblocking filter control syntax element with a value that specifies whether deblocking filter information is present in a second syntax level of the bitstream; decoding, via the first syntax level of the bitstream, a second deblocking filter control syntax element with a value that specifies whether deblocking override is enabled; responsive to the first deblocking filter control syntax element specifying that the deblocking filter information is present in the second syntax level of the bitstream and regardless of the value of the second deblocking filter control syntax element, decoding, via the second syntax level, one or more syntax elements that specify deblocking filter information; and applying, based on the deblocking filter information, a deblocking filter to a block of the video data.

High-level deblocking filter (DBF), adaptive loop filter (ALF) and sample adaptive offset (SAO) control, and adaptation parameter set (APS) number constraint in video coding

A video encoder and/or video decoder are configured to apply an adaptive loop filter to a reconstructed block of video data. The video encoder and/or video decoder may be configured to determine a value of a gradient for a sample in the reconstructed block of video data, including performing a gradient calculation for the sample using an available sample that corresponds to an unavailable sample that is outside of one of: a picture, a slice, a tile, or a tile group that includes the reconstructed block of samples, determine an adaptive loop filter for the reconstructed block of video data based at least in part on the determined value of the gradient for the sample, and apply the determined adaptive loop filter to the reconstructed block of video data to generate a filtered block of video data.

Boundary handling for adaptive loop filtering

An example device for decoding video data includes one or more processors implemented in circuitry and configured to: decode a coding tree unit (CTU) of video data, the CTU including a luminance (luma) block and a chrominance (chroma) block, to produce a decoded luma block and a decoded chroma block; determine that a chroma sample of the decoded chroma block is on a first side of an adaptive loop filter (ALF) virtual boundary and that a co-located luma sample of the decoded luma block is on a second side of the ALF virtual boundary, the co-located luma sample being co-located with the chroma sample, the first side being different than the second side; and in response to determining that the chroma sample is on the first side and the luma sample is on the second side, disable cross-component adaptive loop filtering (CC-ALF) for the chroma sample.

Cross-component adaptive loop filter in video coding

A video decoder can be configured to apply a first stage adaptive loop filter (ALF) to a reconstructed sample by determining a first class index for the reconstructed sample, selecting a filter from a first set of filters based on the first class index, and applying the filter from the first set of filters to the reconstructed sample to determine a first intermediate sample value; apply a second stage ALF to the reconstructed sample by determining a second class index for the reconstructed sample; select a second filter from a second set of filters based on the second class index, applying the second filter to the reconstructed sample to determine a first sample modification value, and determining a second sample modification value based on the first intermediate sample value; and determine a filtered reconstructed sample based on the reconstructed sample and the first and second sample modification values.

Adaptive loop filter with fixed filters

In one example, a device for decoding video data includes one or more processors implemented in circuitry and configured to: determine that a value for a syntax element representing a number of profile-tier-level (PTL) data structures in a video parameter set (VPS) of a bitstream is equal to a total number of output layer sets (OLSs) specified for the VPS; in response to determining that the value for the syntax element representing the number of profile-tier-level data structures in the VPS is equal to the total number of OLSs specified for the VPS, infer values for OLS PTL index values, without explicitly decoding values for the OLS PTL index values; and decode video data of one or more OLSs using corresponding PTL data structures of the PTL data structures in the VPS according to the inferred values for the OLS PTL index values.

Coding output layer set data and conformance window data of high level syntax for video coding

Example techniques are described for coding video data by obtaining a block of video data, obtaining an adaptive parameter set, determining a set of adaptive loop filter parameters for a plurality of filters for the block of video data based on the adaptive parameter set, wherein a plurality of adaptive loop parameters of the set of adaptive loop filter parameters are signaled using the same signaling parameter for each of the plurality of filters of the adaptive parameter set, and coding the block of video data using the set of adaptive loop filter parameters. The example techniques can be performed as part of an encoding or decoding process and/or by an encoder or a decoder.

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Nan Hu