The influence of perceived quality by adjusting frames per second and bits per frame under the limited bandwidth

Under the limited bandwidth, MPEG-4 video coding stream with Fine Granularity Scalability can be flexibly dropped by very fine granularity to adapt to the available network bandwidth. Therefore, we can either reduce the frame rate, i.e., reduce the frames per second(FPS), by dropping partial frames to keep the spatial sharpness of an image or reduce the bits per frame(BPF) to keep the temporal continuity of a video. We attempt to understand that different content characteristics for the above two schemes affect the visual perceived quality when the bandwidth is limited. In this paper, the double stimulus continuous quality evaluation(DSCQE) is used as our subjective measurement. In our experiment, the subjects assess the scores of perceived quality by comparing the reference sequences with the test sequences for different content characteristics. We find that video contents with low motion characteristic suit to low frame rate and video contents with high motion characteristic suit to high frame rate under the limited bandwidth. The perceived quality of the spatial sharpness for the detailed texture sequences is influenced more than the easy texture sequences when the bit rate is increased.