Entropy coding transform blocks

An electronic apparatus comprising:

• a video coder circuit configured to perform operations comprising:
• receiving input data associated with the current block, wherein the input data correspond to quantized transform coefficients associated with the current block to be entropy encoded at an encoder side or the input data correspond to coded quantized transform coefficients associated with the current block to be decoded at a decoder side, wherein the transform coefficients are generated by a transform belonging to a two-dimensional non-separable transform type;
• encoding or decoding a position of a last significant transform coefficient according to a predefined scan order for a transform block, wherein encoding or decoding the position of the last significant transform coefficient comprises encoding or decoding an index of the last significant transform coefficient according to the predefined scan order;
• and
• encoding or decoding transform coefficients of the transform block using ordering information of the predefined scan order based on the position of the last significant transform coefficient.

A video encoding method comprising:

• receiving pixel data to be encoded as a current block of pixels of a current picture of a video;
• generating transform coefficients of a transform block based on the received pixel data;
• encoding transform coefficients of the transform block according to a scan order based on a position of a last significant transform coefficient in the transform block;
• encoding the position of the last significant transform coefficient, wherein the position is indicated as an index in the scan order;
• and
• signaling the encoded transform coefficients and the encoded position in a bitstream.

A video decoding method comprising:

• receiving data to be decoded as a current block of pixels of a current picture of a video;
• decoding the received data for a position of a last significant transform coefficient in a transform block, wherein the position is indicated as an index in a scan order for the transform block;
• decoding the received data for transform coefficients of the transform block according to the scan order based on the decoded position of the last significant transform coefficient when a transform type of the transform block indicates low-frequency non-separable transform (LFNST) or non-separable primary transform (NSPT) transform;
• and
• reconstructing the current block by inverse transforming the transform block.