Low Latency Live Video Streaming over HTTP 2.0

Abstract

Hypertext Transfer Protocol (HTTP) has been widely adopted as a scalable and efficient protocol for streaming video content over the Internet. HTTP streaming clients receive a manifest file, download the referred video segments over HTTP, and play them back seamlessly emulating video streaming. This introduces at least one segment duration latency making HTTP streaming unsuitable for live video streaming use cases that require low latencies. The straightforward solution to lower live latency that reduces segment duration leads to an explosion in the number of HTTP requests, as well as inefficient deployment of assets in HTTP caches. To solve this problem, we develop a low latency live video streaming technique over HTTP 2.0. In particular, we employ the new server push feature in HTTP 2.0 to stream the live video actively from the web server to the client, as soon as the video segments become available. We implement this server push based low latency mechanism in a MPEG Dynamic Adaptive Streaming over HTTP (DASH) prototype. Our experimental results indicate performance gains in live latency using the server push scheme. More importantly, by leveraging the server push feature in HTTP 2.0, we are able to avoid the request explosion problem while lowering latency by reducing the segment duration.