Single-index quantization matrix design for video encoding and decoding

An apparatus, comprising:

• one or more processors, wherein said one or more processors are configured to:
• obtain a single identifier for a quantization matrix, based on a block size identifier, a color component type, and a prediction mode of a block to be decoded in a picture, wherein an Intra Block Copy prediction mode is considered as an Inter prediction mode when obtaining said single identifier, and wherein said single identifier is obtained based on N*sizeId+matrixTypeId, where matrixTypeId indicates said color component type and said prediction mode of said block, N is a number of possible type identifiers indicated by matrixTypeId, and sizeId indicates said block size identifier;
• decode a syntax element indicating a reference quantization matrix, wherein said syntax element specifies a difference between an identifier of said reference quantization matrix and said single identifier for said quantization matrix;
• obtain said quantization matrix based on said reference quantization matrix;
• de-quantize transform coefficients for said block based onto said quantization matrix;
• and
• decode said block based on said de-quantized transform coefficients.

A method, comprising:

• accessing a quantization matrix for a block to be encoded in a picture;
• obtaining a single identifier for said quantization matrix, based on a block size identifier, a color component type, and a prediction mode of said block, wherein an Intra Block Copy prediction mode is considered as an Inter prediction mode when obtaining said single identifier, and wherein said single identifier is obtained based on N*sizeId+matrixTypeId, where matrixTypeId indicates said color component type and said prediction mode of said block, N is a number of possible type identifiers indicated by matrixTypeId, and sizeId indicates said block size identifier;
• encoding a syntax element indicating a reference quantization matrix, wherein said syntax element specifies a difference between an identifier of said reference quantization matrix and said single identifier for said quantization matrix;
• quantizing transform coefficients for said block based on said quantization matrix;
• and
• entropy encoding said quantized transform coefficients.

An apparatus, comprising:

• one or more processors, wherein said one or more processors are configured to:
• access a quantization matrix for a block to be encoded in a picture;
• obtain a single identifier for said quantization matrix, based on a block size identifier, a color component type, and a prediction mode of said block, wherein an Intra Block Copy prediction mode is considered as an Inter prediction mode when obtaining said single identifier, and wherein said single identifier is obtained based on N*sizeId+matrixTypeId, where matrixTypeId indicates said color component type and said prediction mode of said block, N is a number of possible type identifiers indicated by matrixTypeId, and sizeId indicates said block size identifier;
• encode a syntax element indicating a reference quantization matrix, wherein said syntax element specifies a difference between an identifier of said reference quantization matrix and said single identifier for said quantization matrix;
• quantize transform coefficients for said block based on said quantization matrix;
• and
• entropy encode said quantized transform coefficients.