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 implemented by a video decoder including determining, by the video decoder, whether a resolution of a current picture being decoded is the same as the resolution of reference pictures identified by a reference picture list associated with the current picture; enabling, by the video decoder, bi-direction optical flow (BDOF) for a current block of the current picture when the resolution of the current picture is determined to be the same as the resolution of each of the reference pictures; disabling, by the video decoder, the BDOF for the current block of the current picture when the resolution of the current picture is determined to be different than the resolution of either of the reference pictures; and refining, by the video decoder, motion vectors corresponding to the current block using the BDOF when the BDOF is enabled for the current block.

Handling of bi-directional optical flow (BIO) coding tool for reference picture resampling in video coding

A video coding mechanism is disclosed. The mechanism includes partitioning a picture into a plurality of tiles. A number of the tiles are included in a tile group. A flag is also encoded into a parameter set of a bitstream. The flag is set to a first value when the tile group is a raster scan tile group and a second value when the tile group is a rectangular tile group. The tiles are encoded into the bitstream based on the tile group. The bitstream is stored for communication toward a decoder.

Harmonization of raster scan and rectangular tile groups in video coding

A video coding mechanism is disclosed. The mechanism includes receiving an extracted bitstream that is a result of a sub-bitstream extraction process from an input bitstream containing a set of sub-pictures. The extracted bitstream contains only a subset of the sub-pictures of the input bitstream to the sub-bitstream extraction process. A flag from the extracted bitstream is set to indicate that sub-picture information related to the subset of the sub-pictures is present in the extracted bitstream. One or more sub-picture identifiers (IDs) for the subset of the sub-pictures are obtained based on the flag. The subset of the sub-pictures is decoded based on the sub-picture IDs.

Video coding bitstream extraction with identifier signaling

A method of decoding includes receiving a first picture parameter set and a second picture parameter set each referring to same sequence parameter set, the first picture parameter set and the second picture parameter set having same values of a conformance window when the first picture parameter set and the second picture parameter set have same values of picture width and picture height, and applying the conformance window to a current picture corresponding to the first picture parameter set or the second picture parameter set.

Handling of multiple picture size and conformance windows for reference picture resampling 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 encoded into a bitstream. A split indication is encoded into the bitstream. The split indication indicates that at least one of the first level tiles is split into the second level tiles. The bitstream is stored for communication toward a decoder.

Flexible tile signaling in video coding

A method of decoding includes encountering an end of tile bit with a first value and byte alignment bits in a video bitstream, which indicate that a current coding tree block (CTB) is a last CTB in a tile; encountering an end of CTB row bit with the first value and the byte alignment bits in the video bitstream, which indicate that waveform parallel processing (WPP) is enabled and that the current CTB is the last CTB in a CTB row but not the last CTB in the tile; and reconstructing the plurality of CTBs in the tile based on the end of tile bit with the first value, the end of CTB row bit with the first value, and the byte alignment bits.

Wavefront parallel processing for tile, brick, and slice

A video coding mechanism is disclosed. The mechanism includes receiving a bitstream comprising a flag and a picture including a sub-picture with a sub-picture boundary. The sub-picture is decoded. Filtering operations are performed across the sub-picture boundary when the flag is set to a first value. The filtering operations across the sub-picture boundary are omitted when the flag is set to a second value. The sub-picture is forwarded for display as part of a decoded video sequence.

Sub-picture level filtering in video coding

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.

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