Improving image quality and interactivity in free-viewpoint video transmission

Free-viewpoint video, which enables us to change viewpoint of the video freely, attracts rising attention as visual media. Transmitting such media over an IP network, the network delay deteriorates qualities of the media. In this paper, we propose three types of control for the depth and image transmission method in free-viewpoint video transmission. One is buffering control, another is prediction control, and the other is a combination use of both types of control. The buffering control buffers the viewpoint information, and the prediction control predicts the information. We investigate the effects of the three types of control by Quality of Experience (QoE) assessment. Assessment results show that the optimum buffering time and optimum prediction time exist in the buffering control and the prediction control, respectively. Also, the buffering control improves the image quality, but the interactivity is degraded. The image quality becomes higher by the prediction control. Furthermore, there exist the optimum values of the buffering time and prediction time in the combination use, and the use further improves QoE.