An independent construction method for block vector list in intra block copy mode. A method of video processing includes: determining, during a first conversion between a first video block of a video and a bitstream representation of the video, a first candidate list construction method for the first video block with a first coding mode; performing, at least based on a first candidate list acquired according to the first candidate list construction method, the first conversion; where the conversion of the first video block is based on samples in current picture, and the first candidate list construction method is different from a second candidate list construction method which is applied, during a second conversion between a second video block with a second coding mode of the video and the bitstream representation of the video, on the second video block.

A method, apparatus and a non-transitory computer readable medium are provided for receiving an input picture divided into a plurality of coding units (CUs) and comprising a virtual boundaries between a dirty area and a clean area of the input picture, each CU located within either the clean area or the dirty area. The virtual boundary is treated as a picture boundary for coding units within the clean area and as a non-boundary for coding units within the dirty area. For a current CU, a history-based motion vector prediction (HMVP) table can be prepared that identifies other CUs as HMVP candidates for inter prediction, the HMVP candidates being adjacent the current CU. The HMVP candidate CUs are limited to CUs previously coded in the clean area. The current CU can be intra coded based at least upon the HMVP candidates from the HMVP table.

A method, apparatus and a non-transitory computer readable medium are provided for receiving an input picture divided into a plurality of coding units (CUs) and comprising a virtual boundaries between a dirty area and a clean area of the input picture, each CU located within either the clean area or the dirty area. The virtual boundary is treated as a picture boundary for coding units within the clean area and as a non-boundary for coding units within the dirty area. For a current CU, a history-based motion vector prediction (HMVP) table can be prepared that identifies other CUs as HMVP candidates for inter prediction, the HMVP candidates being adjacent the current CU. The HMVP candidate CUs are limited to CUs previously coded in the clean area. The current CU can be intra coded based at least upon the HMVP candidates from the HMVP table.

A system, method, and/or instrumentality may be provided for coding a 360-degree video. A picture of the 360-degree video may be received. The picture may include one or more faces associated with one or more projection formats. A first projection format indication may be received that indicates a first projection format may be associated with a first face. A second projection format indication may be received that indicates a second projection format may be associated with a second face. Based on the first projection format, a first transform function associated with the first face may be determined. Based on the second projection format, a second transform function associated with the second face may be determined. At least one decoding process may be performed on the first face using the first transform function and/or at least one decoding process may be performed on the second face using the second transform function.

Embodiments include systems, methods, and computer-readable media for optimized reduced bitrate encoding for text-based content in video frames. Example methods may include determining that a first segment of video content includes a content scene, determining that a second segment of the video content includes text, and determining a first encoder configuration to encode the first segment of video content, where the first encoder configuration includes a first encoding parameter setting. Example methods may include determining a second encoder configuration to encode the second segment of the video content, where the second encoder configuration includes a second encoding parameter setting, encoding the first segment using the first encoder configuration, and encoding the second segment using the second encoder configuration. The first segment may be encoded at a first bitrate that is greater than a second bitrate at which the second segment is encoded.

Embodiments include systems, methods, and computer-readable media for optimized reduced bitrate encoding for text-based content in video frames. Example methods may include determining that a first segment of video content includes a content scene, determining that a second segment of the video content includes text, and determining a first encoder configuration to encode the first segment of video content, where the first encoder configuration includes a first encoding parameter setting. Example methods may include determining a second encoder configuration to encode the second segment of the video content, where the second encoder configuration includes a second encoding parameter setting, encoding the first segment using the first encoder configuration, and encoding the second segment using the second encoder configuration. The first segment may be encoded at a first bitrate that is greater than a second bitrate at which the second segment is encoded.

An example method of video processing includes making a first determination, for a conversion between a current block of a video and a bitstream representation of the video, about whether a sample in a neighboring block of the current block is in a same video region as the current block and using the first determination to make a second determination about applicability of a coding tool that uses samples outside the current block to the conversion of the current block. The coding tool comprises an adaptive loop filter (ALF) tool that comprises an ALF classification process and/or an ALF filtering process. The method also includes performing the conversion according to the first determination and the second determination.

The present disclosure provides systems and methods for video coding. The systems include, for example, an image encoder comprising: circuitry; and a memory coupled to the circuitry, wherein the circuitry, in operation, performs the following: predicting a first block of prediction samples for a current block of a picture, wherein predicting the first block of prediction samples includes at least a prediction process with a motion vector from a different picture; padding the first block of prediction samples to form a second block of prediction samples, wherein the second block is larger than the first block; calculating at least a gradient using the second block of prediction samples; and encoding the current block using at least the calculated gradient.

The present disclosure provides systems and methods for video coding. The systems include, for example, an image encoder comprising: circuitry; and a memory coupled to the circuitry, wherein the circuitry, in operation, performs the following: predicting a first block of prediction samples for a current block of a picture, wherein predicting the first block of prediction samples includes at least a prediction process with a motion vector from a different picture; padding the first block of prediction samples to form a second block of prediction samples, wherein the second block is larger than the first block; calculating at least a gradient using the second block of prediction samples; and encoding the current block using at least the calculated gradient.

There are disclosed a method and an apparatus for video encoding. The method can include determining that a coding unit is in intra coded area and encoding the coding unit in intra prediction mode into a bitstream unless the intra prediction for the coding unit needs a reference sample for prediction from a dirty area. The method can further include determining that a coding unit is in clean area when the coding unit is encoded in inter prediction mode into a bitstream, the method comprises validating a plurality of inter prediction modes to determine which of the plurality of inter prediction modes do not use reference samples from a dirty area, and defining such inter prediction mode as a valid inter prediction mode. The method further includes encoding into a bitstream that exact-match is required at a recovery point and encoding into a bitstream an indication of a use of a diagonal refresh; and transmitting the encoded bitstream to a decoder.