SVTA1058: An Exploration into Measuring Streaming Latency

This document represents a continuation of the work from SVTA5021: Best Practices for Reducing Live Streaming Latency.

Driven by the increasing priority of video publishers to quantify and reduce latency in live video streaming, this document highlights the key technical contributing factors to latency and, building on [SVTA5021], details the various options available for measuring latency at each component of the video delivery chain, and including the playback device.

Several key measurement methodologies are described in this document, including basic, low-scale mechanisms, such as digital clock applications and embedded visual timestamps, to more sophisticated and scalable mechanisms, such as probes installed throughout the delivery chain. Measurement capabilities unique to the latest low-latency streaming delivery protocols are also explored.

The overall conclusion of this document is that, currently, there is no single measurement point or method that can provide a complete measurement of latency through the delivery chain. Therefore, to achieve a holistic view of latency, we suggest a combination of client-side SDKs and probes deployed on the encoder, transcoder, packager, and in-network.