Qualcomm Incorporated

Huawei Technologies Co., Limited

Fnu Hendry

Ye-Kui Wang

Adarsh Krishnan Ramasubramonian

Jianle Chen

Ying Hai Chen

Krishnakanth Rapaka

Marta Karczewicz

Muhammed Zeyd Coban

Geert Van Der Auwera

Maxim Borisovitch Sychev

Ying Chen

Vadim Seregin

Vladyslav Zakharchenko

Yei-Kui Wang

A method of decoding a coded video bitstream is provided. The method includes obtaining a reference picture list structure for a current slice represented in the coded video bitstream; constructing a reference picture list for the current slice based on the reference picture list structure such that a number of entries in the reference picture list and an order of the entries in the reference picture list are both the same as in the reference picture list structure, wherein the reference picture list contains a plurality of active entries and a plurality of inactive entries; and obtaining, based on at least one active entry of the reference picture list, at least one reconstructed block of the current slice.

Reference picture management in video coding

A method of decoding a coded video bitstream implemented by a video decoder is disclosed. The method includes determining that a coded video sequence (CVS) of the coded video bitstream includes a video coding layer (VCL) network abstraction layer (NAL) unit having a gradual decoding refresh (GDR) network abstraction layer (NAL) unit type (GDR_NUT), the VCL NAL unit having the GDR_NUT containing a GDR picture; initiating decoding of the CVS at the GDR picture; and generating an image according to the CVS as decoded. A corresponding method of encoding is also disclosed.

Gradual decoding refresh in video coding

A method of decoding is provided. The method includes receiving a video bitstream including a picture unit (PU), where a gradual decoding refresh (GDR) flag in a picture header (PH) of the PU has a first value to specify that a picture associated with the PH is a GDR picture; and decoding the GDR picture from the PU to obtain a decoded picture.

Signaling of picture header in video coding

A method of decoding is provided. The method includes receiving a video bitstream including a picture unit (PU), where the PU includes a picture header (PH) network abstraction layer (NAL) unit preceding a first video coding layer (VCL) NAL unit, and decoding a coded picture from the PU to obtain a decoded picture.

A method of decoding a coded video bitstream implemented by a video decoder is provided. The method includes the video decoder determining whether a value for a first flag is provided by an external input; setting a first flag equal to the value provided by the external input and a second flag equal to the value of the first flag to prevent a gradual decoding refresh (GDR) picture from being output when the value for the first flag is provided by the external input; decoding the GDR picture; and storing the GDR picture in a decoded picture buffer (DPB).

A method of decoding includes receiving the coded video bitstream, the coded video bitstream containing reference picture lists; obtaining reference pictures for a current picture from the reference picture lists; setting a motion vector refinement flag to a first value to enable motion vector refinement for a current block of the current picture when the reference pictures are in a same layer as the current picture; setting the motion vector refinement flag to a second value to disable the motion vector refinement for the current block of the current picture when the reference pictures are in a different layer than the current picture; and refining a motion vector corresponding to the current block when the motion vector refinement flag is set to the first value.

Inter coding in video coding with the support of multiple layers

A video coding mechanism is disclosed. The mechanism includes receiving a bitstream comprising a flag and a plurality of sub-pictures associated with a picture. The plurality of sub-pictures are contained in a plurality of video coding layer (VCL) network abstraction layer (NAL) units. The mechanism determines that VCL NAL units of one or more of the sub-pictures of the picture all have a first particular value of NAL unit type and other VCL NAL units in the picture all have a different second particular value of NAL unit type based on a value of the flag. One or more of the sub-pictures are decoded based on the first particular value of NAL unit type and the second particular value of NAL unit type. One or more of the sub-pictures are forwarded for display as part of a decoded video sequence.

Mixed NAL unit type picture constraints

A video coding mechanism is disclosed. The mechanism includes receiving a bitstream comprising a slice and a plurality of adaptation parameter sets (APSs) including a plurality of APS types, wherein each APS includes an APS identifier (ID), and wherein APS IDs for the APS types are assigned in sequence over a plurality of different value spaces. The mechanism further includes decoding the slice using parameters from the plurality of APSs. The mechanism further includes forwarding the slice for display as part of a decoded video sequence.

Adaptation parameter set identifier value spaces in video coding

A video coding mechanism is disclosed. The mechanism includes receiving a bitstream including image data coded in a plurality of slices. A top left tile identifier (ID) and a bottom right tile ID of a first slice are determined. Boundaries of the first slice are determined based on the top left tile ID and the bottom right tile ID. The first slice is decoded to generate a reconstructed image based on the boundaries of the first slice.

Tile based addressing in video coding

A method of decoding includes receiving a coded video bitstream including a current picture; deriving a first reference picture list and a second reference picture list for each slice of the current picture; determining that the current picture is a clean random access (CRA) picture, the CRA picture signifying that there shall be no picture referred to by an entry in the first reference picture list or the second reference picture list that precedes, in an output order or a decoding order, any preceding intra random access point (IRAP) picture in the decoding order; and decoding each slice of the CRA picture based on one or both of the first reference picture list and the second reference picture list.

Types of reference pictures in reference picture lists

A video coding mechanism is disclosed. The mechanism includes receiving a bitstream comprising a sequence parameter set (SPS), one or more sub-pictures partitioned from a picture, and one or more slice headers associated with one or more slices. The SPS is parsed to obtain sub-picture identifiers (IDs) for the one or more sub-pictures. The slice headers are parsed to obtain a current sub-picture ID associated with a current sub-picture. The current sub-picture ID indicating the slices are included in the current sub-picture of the one or more sub-pictures. The current sub-picture is decoded based on the current sub-picture ID to create a video sequence. The video sequence is forwarded for display.

Sub-picture identifier signaling in video coding

A video coding mechanism is disclosed. The mechanism includes receiving a bitstream comprising an adaptive loop filter (ALF) adaptation parameter set (APS) including an ALF luma filter signal flag (alf_luma_filter_signal_flag) and a ALF chroma filter signal flag (alf_chroma_filter_signal_flag), wherein at least one of the alf_luma_filter_signal_flag or the alf_chroma_filter_signal_flag is equal to one. A slice is decoded based on ALF parameters in the ALF APS. The slice is forwarded for display as part of a decoded video sequence.

ALF APS constraints in video coding

A video coding mechanism is disclosed. The mechanism includes partitioning a picture into a plurality of first level tiles. A subset of the first level tiles is partitioned into a plurality of second level tiles. The first level tiles and the second level tiles are assigned into one or more tile groups such that all tiles in an assigned tile group containing the second level tiles are constrained to cover a rectangular region of the picture. The first level tiles and the second level tiles are encoded into a bitstream. The bitstream is stored for communication toward a decoder.

Flexible tiling improvements in video coding

A video coding mechanism includes receiving a bitstream comprising a current picture including a sub-picture coded according to inter-prediction. Coded blocks contain candidate motion vectors for a current block of the sub-picture. The coded blocks include a collocated block from a different picture. A candidate list of candidate motion vectors for the current block are derived by excluding collocated motion vectors from the candidate list when the collocated motion vectors are included in the collocated block, when the collocated motion vectors point outside of the sub-picture, and when a flag is set to indicate the sub-picture is treated as a picture. A current motion vector for the current block is determined from the candidate list of candidate motion vectors. The current block is decoded based on the current motion vector. The current block is forwarded for display as part of a decoded video sequence.

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