To achieve high-quality video streaming on a best-effort network, adaptive video streaming methods for controlling video bitrate in accordance with fluctuation in network throughput have been developed. These methods change the video bitrate in 1-10-second intervals. However, delay of the video increases if the throughput deteriorates drastically, and delay requirements cannot be satisfied when the requirement is short. To resolve this issue, adaptive video-streaming methods using scalable video coding (SVC) have been proposed. By using SVC, the bitrate can be controlled more frequently, and the delay can be reduced. However, the quality of SVC video worsens compared to that of the same bitrate non-SVC video due to coding overhead. The overhead increases as the number of layers increases. This paper proposes a method for adaptively controlling the bitrates of SVC layers. With this method, wide fluctuations in network throughput can be covered by a few layers, and the coding overhead can be reduced. Simulation results indicate that the method improves the video-quality score, which is the bitrate removing the effect of the coding overhead of SVC, by up to 38%.
