# US 12,003,700 B2 · Reference picture management in layered video coding > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,003,700 B2 - Document ID: US12003700B2 - Status: Granted - Kind: B2 - Application number: 17/536,621 - Filed: 2021-11-29 - Published: 2022-03-17 - Granted: 2024-06-04 - Earliest claimed: 2019-05-30 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Ye-Kui Wang; FNU Hendry - Web page: https://patentgrep.com/patent/US12003700B2 ## CPC - H04N 19/105: Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction - H04N 19/33: in the spatial domain - H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction - H04N 19/172: the region being a picture, frame or field - H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) - H04N 19/593: involving spatial prediction techniques - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A video coding mechanism is disclosed. The mechanism includes receiving a bitstream comprising a current picture and a reference picture list structure comprising an inter-layer reference picture flag. The mechanism determines an entry in the reference picture list structure associated with the current picture is an inter-layer reference picture (ILRP) entry based on the inter-layer reference picture flag. The current picture is decoded based on an inter-layer reference picture indicated by the entry in the reference picture list structure when the entry is the ILRP entry. The current picture is forwarded for display as part of a decoded video sequence. ## Claims ### Claim 1 A method implemented by a decoder, the method comprising: receiving a bitstream comprising a current picture and a reference picture list structure comprising an inter-layer reference picture flag, wherein the reference picture list structure is denoted as ref_pic_list_struct(listIdx, rplsIdx) where listIdx identifies a reference picture list, rplsIdx identifies an entry in the reference picture list, and ref_pic_list_struct is a syntax structure; determining an entry in the reference picture list structure associated with the current picture is an inter-layer reference picture (ILRP) entry based on the inter-layer reference picture flag; and decoding the current picture based on an inter-layer reference picture indicated by the entry in the reference picture list structure when the entry is the ILRP entry. ### Claim 2 (depends on 1) The method of claim 1, wherein the reference picture list structure further comprises an ILRP layer indicator, and wherein the method further comprises determining a layer of the inter-layer reference picture based on the ILRP layer indicator when the entry is the ILRP entry. ### Claim 3 (depends on 1) The method of claim 1, wherein the inter-layer reference picture flag is denoted as inter_layer_ref_pic_flag[listIdx][rplsIdx][i], wherein the inter_layer_ref_pic_flag[listIdx][rplsIdx][i] is equal to one when an i-th entry in the ref_pic_list_struct(listIdx, rplsIdx) is the ILRP entry, and wherein the inter_layer_ref_pic_flag[listIdx][rplsIdx][i] is equal to zero when the i-th entry in the ref_pic_list_struct(listIdx, rplsIdx) is not the ILRP entry. ### Claim 4 (depends on 3) The method of claim 3, wherein the ref_pic_list_struct(listIdx, rplsIdx) and the inter_layer_ref_pic_flag[listIdx][rplsIdx][i] are contained in the bitstream in a sequence parameter set (SPS). ### Claim 5 (depends on 1) The method of claim 1, further comprising decoding, by the decoder, the current picture according to intra-layer prediction based on an intra-layer reference picture indicated by the entry in the reference picture list structure when the entry is not the ILRP entry. ### Claim 6 (depends on 1) The method of claim 1, wherein the inter-layer reference picture is in a same access unit (AU) as the current picture, and wherein the inter-layer reference picture is associated with a lower layer identifier than the current picture. ### Claim 7 A method implemented by an encoder, the method comprising: encoding a current picture into a bitstream, the current picture encoded according to inter-layer prediction based on an inter-layer reference picture; encoding a reference picture list structure into the bitstream, the reference picture list structure comprising a plurality of entries for a plurality of reference pictures including an entry associated with the current picture and indicating the inter-layer reference picture, wherein the reference picture list structure is denoted as ref_pic_list_struct(listIdx, rplsIdx) where listIdx identifies a reference picture list, rplsIdx identifies an entry in the reference picture list, and ref_pic_list_struct is a syntax structure; encoding an inter-layer reference picture flag into the bitstream, the inter-layer reference picture flag indicating that the entry associated with the current picture is an inter-layer reference picture (ILRP) entry; and storing the bitstream for communication toward a decoder. ### Claim 8 (depends on 7) The method of claim 7, further comprising encoding, by the encoder, an ILRP layer indicator into the bitstream, the ILRP layer indicator indicating a layer of the inter-layer reference picture. ### Claim 9 (depends on 7) The method of claim 7, wherein the inter-layer reference picture flag is denoted as inter_layer_ref_pic_flag[listIdx][rplsIdx][i], wherein the inter_layer_ref_pic_flag[listIdx][rplsIdx][i] is equal to one when an i-th entry in the ref_pic_list_struct(listIdx, rplsIdx) is the ILRP entry, and wherein the inter_layer_ref_pic_flag[listIdx][rplsIdx][i] is equal to zero when the i-th entry in the ref_pic_list_struct(listIdx, rplsIdx) is not the ILRP entry. ### Claim 10 (depends on 9) The method of claim 9, wherein the ref_pic_list_struct(listIdx, rplsIdx) and the inter_layer_ref_pic_flag[listIdx][rplsIdx][i] are encoded into the bitstream in a sequence parameter set (SPS). ### Claim 11 (depends on 9) The method of claim 9, wherein the ref_pic_list_struct(listIdx, rplsIdx) and the inter_layer_ref_pic_flag[listIdx][rplsIdx][i] are encoded into a header associated with the current picture. ### Claim 12 (depends on 7) The method of claim 7, wherein the inter-layer reference picture is in a same access unit (AU) as the current picture, and wherein the inter-layer reference picture is associated with a lower layer identifier than the current picture. ### Claim 13 A decoder comprising: a receiver configured to receive a bitstream comprising a current picture and a reference picture list structure comprising an inter-layer reference picture flag, wherein the reference picture list structure is denoted as ref_pic_list_struct(listIdx, rplsIdx) where listIdx identifies a reference picture list, rplsIdx identifies an entry in the reference picture list, and ref_pic_list_struct is a syntax structure; and a processor configured to: determine an entry in the reference picture list structure associated with the current picture is an inter-layer reference picture (ILRP) entry based on the inter-layer reference picture flag; and decode the current picture based on an inter-layer reference picture indicated by the entry in the reference picture list structure when the entry is the ILRP entry. ### Claim 14 (depends on 13) The decoder of claim 13, wherein the reference picture list structure further comprises an ILRP layer indicator, and wherein the processor is further configured to determine a layer of the inter-layer reference picture based on the ILRP layer indicator when the entry is the ILRP entry. ### Claim 15 (depends on 13) The decoder of claim 13, wherein the inter-layer reference picture flag is denoted as inter_layer_ref_pic_flag[listIdx][rplsIdx][i], wherein the inter_layer_ref_pic_flag[listIdx][rplsIdx][i] is equal to one when an i-th entry in the ref_pic_list_struct(listIdx, rplsIdx) is the ILRP entry, and wherein the inter_layer_ref_pic_flag[listIdx][rplsIdx][i] is equal to zero when the i-th entry in the ref_pic_list_struct(listIdx, rplsIdx) is not the ILRP entry. ### Claim 16 (depends on 15) The decoder of claim 15, wherein the ref_pic_list_struct(listIdx, rplsIdx) and the inter_layer_ref_pic_flag[listIdx][rplsIdx][i] are contained in the bitstream in a sequence parameter set (SPS). ### Claim 17 (depends on 13) The decoder of claim 13, wherein the inter-layer reference picture is in a same access unit (AU) as the current picture, and wherein the inter-layer reference picture is associated with a lower layer identifier than the current picture.