1. A method for video picture intra-prediction estimation, the method comprising: accessing four ‘N×N’ pixel blocks by an intra-prediction estimation device, ‘N’ being an integer value, the four ‘N×N’ pixel blocks comprising luma-related pixels, and the four ‘N×N’ pixel blocks collectively configuring a ‘2N×2N’ pixel block of a video picture; accessing a first pre-determined number of candidate luma intra-prediction modes for each of the four ‘N×N’ pixel blocks by the intra-prediction estimation device, a candidacy of the luma intra-prediction modes being determined based on a predefined measure; identifying, with the intra-prediction estimation device, a presence of one or more luma intra-prediction modes that are common among the candidate luma intra-prediction modes of at least two of the four ‘N×N’ pixel blocks; and performing, by the intra-prediction estimation device, one of: selecting a principal luma intra-prediction mode for the ‘2N×2N’ pixel block from among the one or more luma intra-prediction modes based on identifying the presence of the one or more luma intra-prediction modes that are common among the candidate luma intra-prediction modes of at least two of the four ‘N×N’ pixel blocks, and limiting a partitioning size to a ‘N×N’ pixel block size for a portion of the video picture corresponding to the ‘2N×2N’ pixel block subsequent to identifying an absence of the one or more luma intra-prediction modes that are common among the candidate luma intra-prediction modes of at least two of the four ‘N×N’ pixel blocks.