Patent ID: 11956469
Assignee: HFI INNOVATION INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 14:
15. An apparatus for performing video decoding, comprising: a computer processor configured for receiving video data; and programming executable on the computer processor for video coding by performing steps comprising:
receiving a video bitstream carrying input data associated with a current block in a current video picture;
parsing one or more last significant position syntax for one or more Transform Blocks (TBs) associated with the current block from the video bitstream;
determining a position of a last significant coefficient for each TB from the corresponding last significant position syntax;
determining an inverse transform operation for the current block by inferring inverse secondary transform not be applied to the current block according to the one or more positions of the last significant coefficient and a predefined region or otherwise by parsing a secondary transform index from the video bitstream;
applying inverse primary transform to final transform coefficients of the current block to recover residuals of the current block or applying inverse secondary transform then inverse primary transform to final transform coefficients of the current block to recover residuals of the current block according to the inverse transform operation;
wherein the current block is a current Coding Unit (CU) and the secondary transform index is parsed at the a CU level after parsing all TBs in the current block; and wherein the current block contains one or more luminance (luma) TBs and the current block further comprises one or more chrominance (chroma) TBs, wherein the secondary transform index is adaptively parsed for the one or more luma or chroma TBs according to the one or more positions of the last significant coefficients in the one or more luma or chroma TBs, and the inverse transform operation is performed operation is performed on the one or more luma or chroma TBs based on the parsed secondary transform index; and
decoding the current block in the video picture based on the residuals of the current block.