Real-time video streaming with interactive region-of-interest

High-spatial-resolution videos offer the possibility of viewing an arbitrary region-of-interest (RoI) interactively. In this paper, we focus on a real-time video streaming system with interactive RoI functionality. Real-time video encoding poses a bottleneck for developing such a system. We present some solutions for speeding up the encoding process at the server so it can be performed in real-time. First, we encode only those video slices that intersect the users' RoIs during a given frame-interval. The server load can be further reduced by skipping the downsampling of the static background in the scene. We also make use of the modes and motion vectors information available in the original high-definition bitstream. Experimental results show that the encoding time at the server can be reduced significantly (more than 90% in some cases) without affecting the video quality or increasing the transmission bit-rate.