Livelyzer

Over-the-top (OTT) live video traffic has grown significantly, fueled by fundamental shifts in how users consume video content (e.g., increased cord-cutting) and by improvements in camera technologies, computing power, and wireless resources. A key determining factor for the end-to-end live streaming QoE is the design of the first-mile upstream ingest path that captures and transmits the live content in real-time, from the broadcaster to the remote video server. This path often involves either a Wi-Fi or cellular component, and is likely to be bandwidth-constrained with time-varying capacity, making the task of high-quality video delivery challenging. Today, there is little understanding of the state of the art in the design of this critical path, with existing research focused mainly on the downstream distribution path, from the video server to end viewers. To shed more light on the first-mile ingest aspect of live streaming, we propose Livelyzer, a generalized active measurement and black-box testing framework for analyzing the performance of this component in popular live streaming software and services under controlled settings. We use Livelyzer to characterize the ingest behavior and performance of several live streaming platforms, identify design deficiencies that lead to poor performance, and propose best practice design recommendations to improve the same.