On Crowdsourced Interactive Live Streaming: A Twitch.TV-Based Measurement Study
This work addresses quality and experience issues for users of crowdsourced live streaming platforms like Twitch, but it is incremental as it provides initial measurements without proposing new solutions.
The study measured Twitch.tv's crowdsourced live streaming, finding that viewer patterns are driven by events and broadcaster sources, and identified that current delay strategies significantly impact interactive experience, with broadcast latency averaging 30 seconds versus 1 second for live messaging, and dynamic upload capacity affects streaming smoothness.
Empowered by today's rich tools for media generation and collaborative production, the multimedia service paradigm is shifting from the conventional single source, to multi-source, to many sources, and now toward {\em crowdsource}. Such crowdsourced live streaming platforms as Twitch.tv allow general users to broadcast their content to massive viewers, thereby greatly expanding the content and user bases. The resources available for these non-professional broadcasters however are limited and unstable, which potentially impair the streaming quality and viewers' experience. The diverse live interactions among the broadcasters and viewers can further aggravate the problem. In this paper, we present an initial investigation on the modern crowdsourced live streaming systems. Taking Twitch as a representative, we outline their inside architecture using both crawled data and captured traffic of local broadcasters/viewers. Closely examining the access data collected in a two-month period, we reveal that the view patterns are determined by both events and broadcasters' sources. Our measurements explore the unique source- and event-driven views, showing that the current delay strategy on the viewer's side substantially impacts the viewers' interactive experience, and there is significant disparity between the long broadcast latency and the short live messaging latency. On the broadcaster's side, the dynamic uploading capacity is a critical challenge, which noticeably affects the smoothness of live streaming for viewers.