Face Region Based Conversational Video Coding

Face regions are visual focuses in conversational video communications, thus better reconstruction quality of the regions of interest (ROI) is highly desired or necessary in the bandwidth-constrained conversational video coding. In this paper, we introduce an efficient motion based face detection method to identify face blocks in the first step, which can reduce computational complexity substantially without any loss in face detection results. Then an active contour model is applied to find face contours for more refined and compact face regions. Based on the well-located and compact face regions, facial feature priority based bit allocation is proposed for face ROI based conversational video coding. Experimental results demonstrate that the proposed face region based coding can considerably improve the coding results in the face regions, compared with two other relevant video coding schemes, in terms of objective rate-distortion performance as well as subjective visual quality.