Several techniques for video encoding and video decoding are described. An example method of processing video data includes performing a conversion between a video including one or more subpictures and a bitstream of the video according to a format rule, wherein the format rule specifies that a first syntax element in a scalable nesting supplemental enhancement information message in the bitstream is set to a particular value in response to the scalable nesting supplemental enhancement information message including one or more subpicture level information supplemental enhancement information messages, and wherein the particular value of the first syntax element indicates that the scalable nesting supplemental enhancement information message includes one or more scalable-nested supplemental enhancement information messages that apply to a specific output video layer set.

In an example method, a system receives a plurality of frames of a video, and generates a data structure representing the video and representing a plurality of temporal layers. Generating the data structure includes: (i) determining a plurality of quality levels for presenting the video, where each of the quality levels corresponds to a different respective sampling period for sampling the frames of the video, (ii) assigning, based on the sampling periods, each of the frames to a respective one of the temporal layers of the data structure, and (iii) indicating, in the data structure, one or more relationships between (a) at least one the frames assigned to at least one of the temporal layers of the data structure, and (b) at least another one of the frames assigned to at least another one of the temporal layers of the data structure. Further, the system outputs the data structure.

Region of interest (ROI)-based upscaling for video conferences, the method including: identifying, in a video frame of a video conference at a first resolution, a boundary region for an object; applying, to a portion of the video frame bound by the boundary region, a machine learning upscaling algorithm to generate an upscaled portion of the video frame corresponding to a second resolution; and generating an upscaled video frame at the second resolution by combining a first plurality of pixels in the upscaled portion of the video frame corresponding to the object with a second plurality of pixels.

Region of interest (ROI)-based upscaling for video conferences, the method including: identifying, in a video frame of a video conference at a first resolution, a boundary region for an object; applying, to a portion of the video frame bound by the boundary region, a machine learning upscaling algorithm to generate an upscaled portion of the video frame corresponding to a second resolution; and generating an upscaled video frame at the second resolution by combining a first plurality of pixels in the upscaled portion of the video frame corresponding to the object with a second plurality of pixels.

The present invention relates to an image information decoding method. The decoding method includes receiving a bit stream including a Network Abstraction Layer (NAL) unit that includes information related to encoded image, and parsing a NAL unit header of the NAL unit. The NAL unit header may not include 1 bit flag information that represents whether a picture is a non-reference picture or a reference picture in the entire bit stream during encoding.

The present invention relates to an image information decoding method. The decoding method includes receiving a bit stream including a Network Abstraction Layer (NAL) unit that includes information related to encoded image, and parsing a NAL unit header of the NAL unit. The NAL unit header may not include 1 bit flag information that represents whether a picture is a non-reference picture or a reference picture in the entire bit stream during encoding.

A method and device for controlling coding tools are provided. The video decoding method includes decoding, from a high level of a bitstream, an enable flag indicating whether one or more coding tools are enabled. The coding tools includes a first coding tool that encodes sample values using luma component mapping based on a piecewise linear model. The method includes acquiring a value of an application flag depending on a value of the enable flag, by setting the application flag indicating whether to apply the coding tools to a predetermined value, or by decoding the application flag from a low level of the bitstream, the application flag including a first application flag indicating whether to apply the first coding tool. The coding tools are operated when the value of the application flag is a value indicating that the coding tools are applied.

A method and device for controlling coding tools are provided. The video decoding method includes decoding, from a high level of a bitstream, an enable flag indicating whether one or more coding tools are enabled. The coding tools includes a first coding tool that encodes sample values using luma component mapping based on a piecewise linear model. The method includes acquiring a value of an application flag depending on a value of the enable flag, by setting the application flag indicating whether to apply the coding tools to a predetermined value, or by decoding the application flag from a low level of the bitstream, the application flag including a first application flag indicating whether to apply the first coding tool. The coding tools are operated when the value of the application flag is a value indicating that the coding tools are applied.

A signaling of the layer ID is described which each of the packets of a multi-layered video signal is associated with. In particular, an efficient way of signaling this layer association is achieved, with nevertheless maintaining the backward compatibility with codecs according to which a certain value of the base layer-ID field is restricted to be non-extendable such as base layer-ID value 0 in the base layer-ID field. Instead of circumventing this restriction specifically with respect to this non-extendable base layer-ID value, the layer-ID of portions of the multi-layer data stream is signaled in an extendable manner by sub-dividing the base layer-ID field into a first sub-field and a second sub-field: whenever the first sub-field of the base layer-ID field fulfills a predetermined criterion, an extension layer-ID field is provided, and if the first sub-field of the base layer-ID field does not fulfill the predetermined criterion, the extension layer-ID field is omitted.

A signaling of the layer ID is described which each of the packets of a multi-layered video signal is associated with. In particular, an efficient way of signaling this layer association is achieved, with nevertheless maintaining the backward compatibility with codecs according to which a certain value of the base layer-ID field is restricted to be non-extendable such as base layer-ID value 0 in the base layer-ID field. Instead of circumventing this restriction specifically with respect to this non-extendable base layer-ID value, the layer-ID of portions of the multi-layer data stream is signaled in an extendable manner by sub-dividing the base layer-ID field into a first sub-field and a second sub-field: whenever the first sub-field of the base layer-ID field fulfills a predetermined criterion, an extension layer-ID field is provided, and if the first sub-field of the base layer-ID field does not fulfill the predetermined criterion, the extension layer-ID field is omitted.