A video processing method is provided to include performing a conversion between a video including a plurality of pictures each including at least one slice and a bitstream of the video, wherein the bitstream conforms to a format rule; wherein the format rule specifies that a first flag in the bitstream indicates whether a picture header syntax structure of a picture is included in a slice header of a slice of the picture; and wherein the format rule specifies that, responsive to any of six flags in a picture parameter set associated with the picture is equal to 1, the first flag is equal to 0.

Techniques and tools for encoding enhancement layer video with quantization that varies spatially and/or between color channels are presented, along with corresponding decoding techniques and tools. For example, an encoding tool determines whether quantization varies spatially over a picture, and the tool also determines whether quantization varies between color channels in the picture. The tool signals quantization parameters for macroblocks in the picture in an encoded bit stream. In some implementations, to signal the quantization parameters, the tool predicts the quantization parameters, and the quantization parameters are signaled with reference to the predicted quantization parameters. A decoding tool receives the encoded bit stream, predicts the quantization parameters, and uses the signaled information to determine the quantization parameters for the macroblocks of the enhancement layer video. The decoding tool performs inverse quantization that can vary spatially and/or between color channels.

A device for decoding video data includes a memory configured to store video data; and one or more processors implemented in circuitry and configured to: determine that a current block of the video data is to be predicted using an angular intra-prediction mode; determine neighboring samples to the current block that will be used to generate a prediction block for the current block according to an angle of the angular intra-prediction mode and that are to be upsampled; calculate predicted samples of the prediction block according to formulas that jointly upsample the neighboring samples that will be used to generate the prediction block and that generate the values for the predicted samples; and decode the current block using the prediction block.

A method for implementing an adaptive colour transform (ACT) mode during image/video encoding and decoding includes performing a conversion between a current video block of a video and a bitstream of the video, wherein the current video block is coded using the ACT mode, wherein the conversion comprises applying an inverse ACT transform on the current video block according to a rule, and wherein the rule specifies that a clipping operation, based on a bit depth of the current video block, is applied to an input of the inverse ACT transform.

A deep learning based compression (DLBC) system trains multiple models that, when deployed, generates a compressed binary encoding of an input image that achieves a reconstruction quality and a target compression ratio. The applied models effectively identifies structures of an input image, quantizes the input image to a target bit precision, and compresses the binary code of the input image via adaptive arithmetic coding to a target codelength. During training, the DLBC system reconstructs the input image from the compressed binary encoding and determines the loss in quality from the encoding process. Thus, the models can be continually trained to, when applied to an input image, minimize the loss in reconstruction quality that arises due to the encoding process while also achieving the target compression ratio.

The present invention relates to a method for encoding/decoding a video. To this end, the method for decoding a video may include: generating a merge candidate list of a current block including at least one merge candidate corresponding to each of a plurality of reference picture lists; determining at least one piece of motion information by using the merge candidate list; and generating a prediction block of the current block by using the determined at least one piece of motion information.

Techniques and tools for encoding enhancement layer video with quantization that varies spatially and/or between color channels are presented, along with corresponding decoding techniques and tools. For example, an encoding tool determines whether quantization varies spatially over a picture, and the tool also determines whether quantization varies between color channels in the picture. The tool signals quantization parameters for macroblocks in the picture in an encoded bit stream. In some implementations, to signal the quantization parameters, the tool predicts the quantization parameters, and the quantization parameters are signaled with reference to the predicted quantization parameters. A decoding tool receives the encoded bit stream, predicts the quantization parameters, and uses the signaled information to determine the quantization parameters for the macroblocks of the enhancement layer video. The decoding tool performs inverse quantization that can vary spatially and/or between color channels.

The present invention relates to a method for encoding/decoding a video. To this end, the method for decoding a video may include: generating a merge candidate list of a current block including at least one merge candidate corresponding to each of a plurality of reference picture lists; determining at least one piece of motion information by using the merge candidate list; and generating a prediction block of the current block by using the determined at least one piece of motion information.

Systems and methods for hinting an encoder are disclosed in which a server monitors for information related to changes in frame rendering, calculates tolerance boundaries, rolling average frame time, and short-term trends in frame time, and uses those calculations to identify a frame time peak. The server then hints a codec (encoder) to modulate the quality settings of frame output in proportion to the size of the frame time peak. In certain embodiments, a renderer records one or more playthroughs in a game environment, sorts a plurality of frames from one or more playthroughs into a plurality of cells on a heatmap, and collects the list of sorted frames. A codec may then encode one or more frames from the list of sorted frames to calculate an average encoded frame size for each cell in the heatmap, and associate each average encoded frame size with a per-cell normalized encoder quality setting.

There are provided methods and apparatus for transform selection in video coding. An apparatus includes a video encoder (300) for encoding at least a block in a picture by selecting a transform (329) to apply to a residue of the block from a set of two or more available transforms (325, 326, 327). The transform is selected based on at least one of an inter prediction mode used to predict at least one reference for the block, one or more values corresponding to a motion vector, a value of a residue of one or more previously encoded blocks, a value of prediction data for the block, one or more transform selections of one or more neighboring reconstructed blocks, and a quantization step applied to transform coefficients for the residue of the block.