A method and apparatus for video coding utilizing a current block, a maximum side of the transform block of the current block corresponds to 64. A scaling matrix is derived from elements of an 8×8 base scaling matrix, where the elements in a bottom-right 4×4 region of the 8×8 base scaling matrix are skipped, either not signaled or set to zero. According to another method, a current block belongs to a current picture in a first color format that has only a first color component. A first scaling matrix is signaled at the video encoder side or parsed at the video decoder side for the first color component of the current block. Signaling any second scaling matrix is disabled at the video encoder side or parsing any second scaling matrix is disabled at the video decoder side for a second or third color component of the current block.

A method and apparatus for video coding utilizing a current block, a maximum side of the transform block of the current block corresponds to 64. A scaling matrix is derived from elements of an 8×8 base scaling matrix, where the elements in a bottom-right 4×4 region of the 8×8 base scaling matrix are skipped, either not signaled or set to zero. According to another method, a current block belongs to a current picture in a first color format that has only a first color component. A first scaling matrix is signaled at the video encoder side or parsed at the video decoder side for the first color component of the current block. Signaling any second scaling matrix is disabled at the video encoder side or parsing any second scaling matrix is disabled at the video decoder side for a second or third color component of the current block.

An example video codec includes memory configured to store the video data and one or more processors implemented in circuitry and communicatively coupled to the memory. The one or more processors are configured to determine that a current mode of coding a current block of the video data is a single tree partitioning mode. Based on the current mode being the single tree partitioning mode, the one or more processors are configured to refrain from determining whether there is a non-DC coefficient for a chroma component of a transform unit (TU) for the current block and refrain from coding a low-frequency non-separable transformation (LFNST) index in response to the refraining of the determination of whether there is the non-DC coefficient. The one or more processors are configured to code the current block in the single partitioning mode with LFNST disabled.

An apparatus for processing a video may receive a quantization parameter (QP) adjustment value associated with a syntax level at the syntax level. In examples, the apparatus may obtain the QP adjustment value associated with the syntax level, for example, via signalling at the syntax level. The apparatus may apply the QP adjustment value to a QP associated with the syntax level to obtain an adjusted QP associated with the syntax level. The syntax level may include a coding block level or a transform unit (TU) level. In examples, if the syntax level is a TU level, the decoder may receive the QP adjustment value for a first CU (for example, a current TU) and obtain a QP for the second TU that precedes the first CU in a coding order based on a QP predictor, for example, instead of the QP adjustment value for the first TU.

A method, apparatus or system for processing video information can involve determining at least one Rice parameter associated with a transform residual coding process applied during encoding of a block of picture information, wherein the Rice parameter is a fixed value, or is determined based on, for example, a frequency region or a coefficient scanning position for the transform residual coding, or a number of neighbors of the block of picture information, and encoding or decoding the block of picture information based on the at least one Rice parameter.

A method, apparatus or system for processing video information can involve determining at least one Rice parameter associated with a transform residual coding process applied during encoding of a block of picture information, wherein the Rice parameter is a fixed value, or is determined based on, for example, a frequency region or a coefficient scanning position for the transform residual coding, or a number of neighbors of the block of picture information, and encoding or decoding the block of picture information based on the at least one Rice parameter.

A method of decoding a coding unit from a coding tree unit of an image frame from a video bitstream. The method comprises determining a scan pattern for a transform block the scan pattern progressing from a current collection to a next collection of the plurality of collections after completing scanning of the current collection; decoding residual coefficients from the video bitstream according to the scan pattern; determining a multiple transform selection index for the coding unit, decoding the multiple transform selection index from the video bitstream if a last significant coefficient encountered along the scan pattern is at or within a threshold cartesian location of the transform block, and determining the multiple transform selection index to indicate that multiple transform selection is not used if the last significant residual coefficient position of the transform block along the scan pattern outside the threshold location; and transforming the decoded residual coefficients.

The present application disclose a picture processing method and apparatus, which are applicable to a video picture processing scenario. The method includes: obtaining at least two transform coefficient blocks, where each of the at least two transform coefficient blocks includes at least two transform coefficients that correspond to different frequency points; determining, according to a preset frequency point scanning order, the transform coefficients that are in the at least two transform coefficient blocks and that correspond to a selected frequency point; and encoding, according to a preset coefficient scanning order, each transform coefficient corresponding to the selected frequency point, to obtain picture encoded information.

The present application disclose a picture processing method and apparatus, which are applicable to a video picture processing scenario. The method includes: obtaining at least two transform coefficient blocks, where each of the at least two transform coefficient blocks includes at least two transform coefficients that correspond to different frequency points; determining, according to a preset frequency point scanning order, the transform coefficients that are in the at least two transform coefficient blocks and that correspond to a selected frequency point; and encoding, according to a preset coefficient scanning order, each transform coefficient corresponding to the selected frequency point, to obtain picture encoded information.

A video processing method includes performing a conversion between a video block of a video and a bitstream of the video according to a rule. The rule specifies whether or how usage of a secondary transform within a video unit is indicated in the bitstream. The secondary transform is applied before quantization or after de-quantization.