Rate Control Optimizing Model for Constraining Over-Saturated Live Streaming Quality

Over-allocated coding resources raise signal fidelity beyond human perceptual capabilities, resulting in substantial bitrate wastage. In this paper, we propose the first rate control optimizing model with the capability of over-saturated quality restriction, particularly for live streaming applications that have limited processing latency. Specifically, we construct a quantization-quality estimation model over a given period, where a multi-stage quality restriction strategy is designed to enforce a given quality restriction on the rate control process. Using the Constant Rate Factor (CRF) as an example, our experimental results indicate that the proposed model achieves 18.54% bitrate savings while reaching 0.06% VQScore improvement on 168 real-life live streams. In terms of its subjective performance, 25 experts were invited to blindly evaluate 15 of those 168 streams, of which 82.93% voted that the proposed method achieved a comparable or superior visual quality compared to the original CRF strategy.