Image coding and decoding method and device

An image decoding method, comprising:

• performing entropy decoding on a received bitstream to obtain values of fields for indicating matching relationship parameters, wherein the matching relationship parameters are parameters used in a process of constructing predicted values and/or reconstructed values of pixels in a video image to be decoded;
• mapping the values of the fields to obtain mapped matching relationship parameters, wherein a value range of the matching relationship parameter is divided into K subordinate value ranges, and accordingly, the mapping is divided into mappings in the K subordinate value ranges, and wherein a mapping relationship for one of the mappings or partial mappings in the value range or the subordinate value range changes as status and/or parameters of current coding change;
• and
• constructing the predicted values and/or the reconstructed values of the pixels in the video image to be decoded according to the mapped matching relationship parameters, wherein
• mapping the values of the fields to obtain the mapped matching relationship parameters includes:
• converting, according to the obtained matching relationship parameters, the values of the fields to be processed, and taking values obtained after the conversion as the mapped matching relationship parameters;
• and/or
• assembling and/or rearranging the values of the fields to be processed of a same type into an array according to a specific rule, and processing the array as the mapped matching relationship parameters.

An image coding apparatus, comprising:

• a matching coding module arranged to perform matching coding on pixels of an input video image to obtain one or more matching relationship parameters, wherein the matching relationship parameters are parameters used in a process of constructing predicted values and/or reconstructed values of the pixels in the input video image;
• a mapping module arranged to map the matching relationship parameters to obtain mapped values of the matching relationship parameters, wherein a value range of the matching relationship parameter is divided into K subordinate value ranges, and accordingly, the mapping is divided into mappings in the K subordinate value ranges, and wherein a mapping relationship for one of the mappings or partial mappings in the value range or the subordinate value range changes as status and/or parameters of current coding change;
• and
• an entropy coding module arranged to perform entropy coding on the mapped values of the matching relationship parameters, wherein
• the mapping module is further arranged to convert, according to existing matching relationship parameters, match relationship parameters to be matched, and take values obtained after the conversion as the mapped values of the relationship parameters to be matched, wherein a value with a relatively high frequency in the value range of the matching relationship parameter is mapped into a relatively small value and a value with a relatively low frequency in the value range of the matching relationship parameter is mapped into a relatively large value;
• and/or
• assemble and/or rearrange matching relationship parameters of a same type into a matching relationship parameter group according to a specific rule, map the matching relationship parameter group, and take the matching relationship parameter group obtained after the mapping as the mapped values of the matching relationship parameters.

An image decoding apparatus, comprising:

• an entropy decoding module arranged to perform entropy decoding on a received bitstream to obtain values of fields for indicating matching relationship parameters, wherein the matching relationship parameters are parameters used in a process of constructing predicted values and/or reconstructed values of pixels in a video image to be decoded;
• a mapping module arranged to map the values of the fields to obtain mapped matching relationship parameters, wherein a value range of the matching relationship parameter is divided into K subordinate value ranges, and accordingly, the mapping is divided into mappings in the K subordinate value ranges, and wherein a mapping relationship for one of the mappings or partial mappings in the value range or the subordinate value range changes as status and/or parameters of current coding change;
• and
• a construction module arranged to construct the predicted values and/or the reconstructed values of the pixels in the video image to be decoded according to the mapped matching relationship parameters, wherein
• the mapping module is further arranged to convert, according to the obtained matching relationship parameters, the values of the fields to be processed, and take values obtained after the conversion as the mapped matching relationship parameters;
• and/or
• assemble and/or rearrange the values of the fields to be processed of a same type into an array according to a specific rule, and process the array as the mapped matching relationship parameters.