# US 11,122,264 B2 · Adaptive loop filter (ALF) coefficients in video coding > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,122,264 B2 - Document ID: US11122264B2 - Status: Granted - Kind: B2 - Application number: 16/704,700 - Filed: 2019-12-05 - Published: 2020-06-11 - Granted: 2021-09-14 - Earliest claimed: 2018-12-06 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Nikolay Mikhaylovich Shlyakhov; Dmytro Rusanovskyy; Vadim Seregin; Marta Karczewicz - Web page: https://patentgrep.com/patent/US11122264B2 ## CPC - H04N 19/117: Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635) - H04N 19/463: by compressing encoding parameters before transmission - H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction - H04N 19/174: the region being a slice, e.g. a line of blocks or a group of blocks - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Techniques are described for temporal prediction for adaptive loop filter (ALF) in video coding. A video coder may determine that temporal prediction for ALF is enabled for one or more intra coded slices of a picture, determine ALF coefficients for one or more blocks of the one or more intra coded slices, for which the temporal prediction for ALF is enabled, based on ALF coefficients of a previously coded picture or slice, and apply the determined ALF coefficients to the one or more blocks to generate one or more filtered blocks. ## Claims ### Claim 1 A method of coding video data, the method comprising: determining that temporal prediction for adaptive loop filter (ALF) is enabled for one or more intra coded slices of a picture, wherein determining that temporal prediction for ALF is enabled comprises determining that temporal prediction for ALF is enabled based on the picture having a temporal index value that is not equal to 0; determining ALF coefficients for one or more blocks of the one or more intra coded slices, for which the temporal prediction for ALF is enabled, based on ALF coefficients of a previously coded picture or slice; and applying the determined ALF coefficients to the one or more blocks to generate one or more filtered blocks. ### Claim 2 (depends on 1) The method of claim 1, wherein determining that temporal prediction for ALF is enabled further comprises determining that temporal prediction for ALF is enabled without determining a slice type of the one or more blocks. ### Claim 3 (depends on 1) The method of claim 1, wherein determining that temporal prediction for ALF is enabled further comprises determining that temporal prediction for ALF is enabled in the case that the picture is not one of intra random access picture (TRAP), random access picture (RAP), instantaneous decoder refresh (IDR), or clean random access (CRA) types. ### Claim 4 (depends on 1) The method of claim 1, wherein determining that temporal prediction for ALF is enabled further comprises determining that temporal prediction for ALF is enabled based on signaled information that is not signaled in a slice header. ### Claim 5 (depends on 1) The method of claim 1, wherein determining ALF coefficients for the one or more blocks based on ALF coefficients of the previously coded picture or slice comprises determining ALF coefficients of one or more blocks of an intra coded slice of the picture based on ALF coefficients of an inter coded slice of the picture. ### Claim 6 (depends on 1) The method of claim 1, wherein applying the determined ALF coefficients to the one or more blocks to generate one or more filtered blocks comprises applying the determined ALF coefficients, subsequent to a decoding process, to generate the one or more filtered blocks. ### Claim 7 (depends on 1) The method of claim 1, wherein applying the determined ALF coefficients to the one or more blocks to generate one or more filtered blocks comprises applying the determined ALF coefficients, subsequent to a reconstruction process in a video encoder, to generate the one or more filtered blocks. ### Claim 8 A device for coding video data, the device comprising: memory configured to store ALF coefficients of a previously coded picture or slice; and processing circuitry coupled to the memory and configured to: determine that temporal prediction for adaptive loop filter (ALF) is enabled for one or more intra coded slices of a picture, wherein to determine that temporal prediction for ALF is enabled, the processing circuitry is configured to determine that temporal prediction for ALF is enabled based on the picture having a temporal index value that is not equal to 0; determine ALF coefficients for one or more blocks of the one or more intra coded slices, for which the temporal prediction for ALF is enabled, based on the ALF coefficients of the previously coded picture or slice stored in memory; and apply the determined ALF coefficients to the one or more blocks to generate one or more filtered blocks. ### Claim 9 (depends on 8) The device of claim 8, wherein to determine that temporal prediction for ALF is enabled, the processing circuitry is further configured to determine that temporal prediction for ALF is enabled without determining a slice type of the one or more blocks. ### Claim 10 (depends on 8) The device of claim 8, wherein to determine that temporal prediction for ALF is enabled, the processing circuitry is further configured to determine that temporal prediction for ALF is enabled in the case that the picture is not one of intra random access picture (IRAP), random access picture (RAP), instantaneous decoder refresh (IDR), or clean random access (CRA) types. ### Claim 11 (depends on 8) The device of claim 8, wherein to determine that temporal prediction for ALF is enabled, the processing circuitry is further configured to determine that temporal prediction for ALF is enabled based on signaled information that is not signaled in a slice header. ### Claim 12 (depends on 8) The device of claim 8, wherein to determine ALF coefficients for the one or more blocks based on ALF coefficients of the previously coded picture or slice, the processing circuitry is configured to determine ALF coefficients of one or more blocks of an intra coded slice of the picture based on ALF coefficients of an inter coded slice of the picture. ### Claim 13 (depends on 8) The device of claim 8, wherein to apply the determined ALF coefficients to the one or more blocks to generate one or more filtered blocks, the processing circuitry is configured to apply the determined ALF coefficients, subsequent to a decoding process, to generate the one or more filtered blocks. ### Claim 14 (depends on 8) The device of claim 8, wherein to apply the determined ALF coefficients to the one or more blocks to generate one or more filtered blocks, the processing circuitry is configured to apply the determined ALF coefficients, subsequent to a reconstruction process in a video encoder, to generate the one or more filtered blocks. ### Claim 15 (depends on 8) The device of claim 8, wherein the device comprises a wireless communication device. ### Claim 16 A non-transitory computer-readable storage medium having instructions stored thereon that when executed cause one or more processors of a device for coding video data to: determine that temporal prediction for adaptive loop filter (ALF) is enabled for one or more intra coded slices of a picture, wherein the instructions that cause the one or more processors to determine that temporal prediction for ALF is enabled comprise instructions that cause the one or more processors to determine that temporal prediction for ALF is enabled based on the picture having a temporal index value that is not equal to 0; determine ALF coefficients for one or more blocks of the one or more intra coded slices, for which the temporal prediction for ALF is enabled, based on ALF coefficients of a previously coded picture or slice; and apply the determined ALF coefficients to the one or more blocks to generate one or more filtered blocks. ### Claim 17 (depends on 16) The non-transitory computer-readable storage medium of claim 16, wherein the instructions that cause the one or more processors to determine that temporal prediction for ALF is enabled further comprise instructions that cause the one or more processors to determine that temporal prediction for ALF is enabled without determining a slice type of the one or more blocks. ### Claim 18 (depends on 16) The non-transitory computer-readable storage medium of claim 16, wherein the instructions that cause the one or more processors to determine that temporal prediction for ALF is enabled further comprise instructions that cause the one or more processors to determine that temporal prediction for ALF is enabled in the case that the picture is not one of intra random access picture (TRAP), random access picture (RAP), instantaneous decoder refresh (IDR), or clean random access (CRA) types. ### Claim 19 (depends on 16) The non-transitory computer-readable storage medium of claim 16, wherein the instructions that cause the one or more processors to determine that temporal prediction for ALF is enabled further comprise instructions that cause the one or more processors to determine that temporal prediction for ALF is enabled based on signaled information that is not signaled in a slice header. ### Claim 20 (depends on 16) The non-transitory computer-readable storage medium of claim 16, wherein the instructions that cause the one or more processors to determine ALF coefficients for the one or more blocks based on ALF coefficients of the previously coded picture or slice comprise instructions that cause the one or more processors to determine ALF coefficients of one or more blocks of an intra coded slice of the picture based on ALF coefficients of an inter coded slice of the picture. ### Claim 21 (depends on 16) The non-transitory computer-readable storage medium of claim 16, wherein the instructions that cause the one or more processors to apply the determined ALF coefficients to the one or more blocks to generate one or more filtered blocks comprise instructions that cause the one or more processors to apply the determined ALF coefficients, subsequent to a decoding process, to generate the one or more filtered blocks. ### Claim 22 (depends on 16) The non-transitory computer-readable storage medium of claim 16, wherein the instructions that cause the one or more processors to apply the determined ALF coefficients to the one or more blocks to generate one or more filtered blocks comprise instructions that cause the one or more processors to apply the determined ALF coefficients, subsequent to a reconstruction process in a video encoder, to generate the one or more filtered blocks. ### Claim 23 A device for coding video data, the device comprising: means for determining that temporal prediction for adaptive loop filter (ALF) is enabled for one or more intra coded slices of a picture, wherein the means for determining that temporal prediction for ALF is enabled comprises means for determining that temporal prediction for ALF is enabled based on the picture having a temporal index value that is not equal to 0; means for determining ALF coefficients for one or more blocks of the one or more intra coded slices, for which the temporal prediction for ALF is enabled, based on ALF coefficients of a previously coded picture or slice; and means for applying the determined ALF coefficients to the one or more blocks to generate one or more filtered blocks. ### Claim 24 (depends on 23) The device of claim 23, wherein the means for determining that temporal prediction for ALF is enabled further comprises means for determining that temporal prediction for ALF is enabled without determining a slice type of the one or more blocks. ### Claim 25 (depends on 23) The device of claim 23, wherein the means for determining that temporal prediction for ALF is enabled further comprises means for determining that temporal prediction for ALF is enabled in the case that the picture is not one of intra random access picture (IRAP), random access picture (RAP), instantaneous decoder refresh (IDR), or clean random access (CRA) types. ### Claim 26 (depends on 23) The device of claim 23, wherein the means for determining that temporal prediction for ALF is enabled further comprises means for determining that temporal prediction for ALF is enabled based on signaled information that is not signaled in a slice header. ### Claim 27 A device for decoding video data, the device comprising: memory configured to store ALF coefficients of a previously decoded picture or slice; and processing circuitry coupled to the memory and configured to: determine that temporal prediction for adaptive loop filter (ALF) is enabled for one or more intra decoded slices of a picture, wherein to determine that temporal prediction for ALF is enabled, the processing circuitry is configured to determine that temporal prediction for ALF is enabled without determining a slice type of the one or more blocks; determine ALF coefficients for one or more blocks of the one or more intra decoded slices, for which the temporal prediction for ALF is enabled, based on the ALF coefficients of the previously decoded picture or slice stored in memory; and apply the determined ALF coefficients to the one or more blocks to generate one or more filtered blocks.