Low complexity content-aware video retargeting for mobile devices

In this paper, a low complexity content-aware video retargeting method suitable for mobile multimedia devices is presented. We propose two types of energy functions for intra- and inter-frames to obtain the pixel significance in the video frames. Since the energy functions are defined using only the compressed-domain information such as discrete cosine transform (DCT) coefficients and motion vectors (MVs), instead of fully decoded pixel domain information, the spatiotemporal energy map can be constructed without excessive computations. Based on the proposed energy function, we also introduce a fast seam carving method for mobile devices that carves out the one-dimensional (1-D) seams without annoying artifacts such as jitter and flicker, taking into account the object motion based on MVs. Experimental results show that the proposed video retargeting scheme can achieve high subjective quality with significantly reduced computational loads as compared with existing methods.