StreamLens: An Open-Source ABR Simulation Environment for Multi-Region Buffering, Seeking, and Prefetching

Bei Zhao
Jinhui Song
Jiayu Zhu
Yih‑Chun Hu
2026
Google Scholar

Abstract

ABR simulators are useful for studying ABR behavior under different network conditions. SABRE is an open-source simulator for evaluating ABR algorithms with different videos, network traces,
and ABR policies. However, SABRE has several limitations. First, it does not accurately emulate user seeks or their impact on the viewing experience. Second, it provides limited support for nonlinear buffering, where the client buffers non-contiguous video chunks. Furthermore, SABRE does not provide adequate analysis and visualization support for interpreting simulation results. This paper presents StreamLens, an advanced video simulator that supports: 1) pluggable ABR policies, including BOLA, BOLA-E, Dynamic, DynamicDash, and throughput-based policy; 2) configurable user seeks; 3) nonlinear buffering with customizable prefetching policy; 4) browser-based viewer for result visualization, including
stalls, seeks, rebuffering time, QoE, bitrate, buffer, etc. StreamLens allows developers to configure videos, network traces, and seek patterns, and to evaluate ABR performance across different setups, including ABR policies, linear versus nonlinear buffering, and user seek traces. It also provides metrics and visualizations that help developers inspect streaming behavior in a straightforward way. Several predefined scenarios are included as both evaluation examples and configuration templates, covering synthetic seek and prefetch settings, session-replay workflows, generated reports, and regression tests. The software is available publicly at
https://github.com/Slothbetty/StreamLens.

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