Implementation and evaluation of fast mobile vnc systems

VNC (virtual network computing) is a popular tool for sharing an application, allowing users to access graphic displays remotely. In mobile VNC systems, it has been challenging to increase screen update rate by fast screen image encoding. In this paper, we implement a prototype system for mobile VNC, and several works are done for improving screen update rate. At first, a number of video encoders are integrated into a prototype system, and we investigate what is the most suitable codec for mobile VNC. The existing RFB protocol is extended straightforwardly to integrate video codecs. Next, the overall system architecture is modified from serial operation to parallel. Finally, we propose a modified region coding to further reduce the encoding time of screen images. The proposed methods are implemented into our prototype mobile VNC system, and practical performances are widely evaluated. We report that JPEG is the most suitable for mobile VNC in terms of both complexity and compression ratio. In addition, the proposed modified region coding can decrease encoding time, and consequently increase screen update rate.