An attention based spatial adaptation scheme for H.264 videos on mobiles

With the growing popularity of personal digital assistant devices and smart phones, consumers have become increasingly enthusiastic to watching videos from these mobile devices. However, when browsing videos in mobiles, users often feel that the display resolution greatly affects their perceptual experience with the limited screen size. In this paper, an attention based spatial video adaptation scheme is proposed to overcome the display constraints by producing and displaying the region of interest. According to the size of the target display, we automatically detect and crop the informative region in each frame to generate a smooth sequence. To avoid costly full encoding operations, we develop a set of transcoding techniques based on the H.264 standard. Experimental results show that this approach not only improves the perceptual quality but also saves the bandwidth and computation, especially for the videos which have not been well edited.