Sample adaptive offset (SAO) adjustment method and apparatus and SAO adjustment determination method and apparatus

A video decoding method comprising:

• obtaining left offset merging information of a current block by performing entropy decoding on a bitstream;
• when the left offset merging information indicates that the offset parameter of the current block is not determined according to the offset parameter of a left block, obtaining upper offset merging information of the current block by performing entropy decoding on the bitstream;
• when the upper offset merging information indicates that the offset parameter of the current block is not determined according to an offset parameter of an upper block, obtaining the offset parameter of the current block from the bitstream;
• and
• compensating for samples of the current block by using offset values,
• wherein the offset parameter comprises at least one of offset type information and the offset values,
• the offset type information indicates an offset type or whether to apply an offset to the current block, and the offset type is one of a band offset type and an edge offset type,
• the obtaining the offset parameter of the current block from the bitstream comprises:
• when the offset type information of the current block indicates the band offset type or the edge offset type, obtaining absolute values of the offset of the current block by performing entropy decoding on the bitstream in bypass mode;
• and
• in response to determining that the offset type information of the current block indicates the band offset type and the absolute values of the offset values are not zero, obtaining a class indicating a starting point of bands of the current block by performing entropy decoding on the bitstream,
• when one bit of the left offset merging information is obtained from the bitstream, the one bit of the left offset merging information is applied to luma components, Cr chroma components and Cb chroma components of the current block,
• when one bit of the upper offset merging information is obtained from the bitstream, the one bit of the upper offset merging information is applied to the luma components, the Cr chroma components and the Cb chroma components of the current block, and
• when an offset type for the Cr chroma components determined by offset type information for the Cr chroma components of the current block, an offset type for the Cb chroma components of the current block is determined to be identical to the offset type for the Cr chroma components.