AN ENCODER, A DECODER AND CORRESPONDING METHODS FOR PERFORMING CHROMA DEBLOCKING FOR BLOCKS WHICH USE JOINT CHROMA CODING

摘要

A deblocking method, for deblocking a chroma block edge (903, 913, 923, 933, 943, 953, 963, 973) between a first chroma block (901, 911, 921, 931, 941, 951, 961, 971) of a first image block (601, 601') and a second chroma block (902, 912, 922, 932, 942, 952, 962, 972) of a second image block (602, 602'), in an image encoding and/or an image decoding, wherein the deblocking method comprises: performing a decision process for the chroma block edge, wherein the decision process comprises: determining a first chroma quantization parameter (Qp_Cp) for the first chroma block (901, 911, 921, 931, 941, 951, 961, 971) based on a first luma quantization parameter (Qp_YP) of a first luma block (801) of the first image block (601, 601') and a chroma QP mapping table for the first chroma block; determining a second chroma quantization parameter (Qp_Cq) for the second chroma block (902, 912, 922, 932, 942, 952, 962, 972) based on a second luma quantization parameter (Qp_YQ) of a second luma block (802) of the second image block (602, 602') and a chroma QP mapping table for the second chroma block; determining an averaged and rounded chroma quantization parameter (Qp_C) based on the first chroma quantization parameter (Qp_Cp) and the second chroma quantization parameter (Qp_Cq); and determining a threshold parameter (t_C) based on the averaged and rounded chroma quantization parameter (Qp_C); and performing a filtering process for the chroma block edge based on the threshold parameter (t_C).