Cross: A Delay Based Congestion Control Method for RTP Media

TL;DR

Cross is a delay-based congestion control method designed for RTP media that improves bandwidth utilization and reduces video freezing in high-quality real-time communication applications.

Contribution

The paper introduces Cross, a novel delay-based congestion control algorithm optimized for high-definition RTC, validated through simulation and online deployment.

Findings

Achieves low queuing delay and high channel utilization in simulations.

Reduces video freezing ratio by up to 58.45% in online tests.

Outperforms benchmark algorithms in high-rate RTC scenarios.

Abstract

After more than a decade of development, real time communication (RTC) for video telephony has made significantly progress. However, emerging high-quality RTC applications with high definition and high frame rate requires sufficient bandwidth. The default congestion control mechanism specifically tuned for video telephony leaves plenty of room for optimization under high-rate scenarios. It is necessary to develop new rate control solutions to utilize bandwidth efficiently and to provide better experience for such services. A delay-based congestion control method called Cross is proposed, which regulates rate based on queue load with a multiplicative increase and multiplicative decrease fashion. A simulation module is developed to validate the effectiveness of these congestion control algorithms for RTC services. The module is released with the hope to provide convenience for RTC research community. Simulation results demonstrate that Cross can achieve low queuing delay and maintain high channel utilization under random loss environments. Online deployment shows that Cross can reduce the video freezing ratio by up to 58.45\% on average when compared with a benchmark algorithm.