Processing methods and apparatuses for video data of a color component comprise receiving input data associated with a current coding block (CB) in a current slice, where the video data is partitioned into multiple CBs according to a partitioning method. A Quantization Parameter (QP) minimum block area or a depth flag is determined and an area of the current CB according to a width and a height or a combined depth of the current CB is calculated and compared with the QP minimum block area or the depth flag. Signaling of QP information for the current CB is conditioned by the comparing result. The QP information for the current CB is used to quantize a residual signal of the current CB or recovering a quantized residual signal of the current CB.