Content to cash: Understanding and improving crowdsourced live video broadcasting services with monetary donations

摘要

Crowdsourced live video broadcasting (livecast) services such as Twitch and Douyu have become increasingly popular in recent years. In such a service, how to allocate limited service capacities, including video transcoding and delivery capacities among numerous channels, is a critical problem. Previous studies allocate capacities based on popularity. In this paper, we analyze Douyu, a leading crowdsourced livecast website in China, with a measurement approach. We find that Douyu is deployed upon a video delivery network (VDN), and it prioritizes popular channels when allocating service capacities; we also find that viewers' willingness to donate monetary gifts in a channel is closely related to their streaming experiences, which are decided by service capacities allocated in the channel. On the other hand, a livecast channel's profitability is only moderately correlated to its popularity. In other words, there exists a mismatch between the popularity-based service strategies and Douyu's business model. Motivated by our analysis, we propose that channels' profitability as well as popularity should be considered in capacity allocating. We present proactive and reactive algorithms, which balance viewers' satisfaction with system's monetary profit, for allocating transcoding capacity among livecast channels. We also propose a practical strategy for VDN edge nodes to select channels to replicate, by taking channels' popularity, profitability, and bandwidth consumptions into consideration. Experiments driven by real-world measurement data show that our proposed solutions can effectively improve the overall benefits for a crowdsourced livecast system and individual VDN edge nodes, and avoid adjusting channels' transcoding schemes too often during livecast sessions.