HTTP/2

Abstract: In HTTP Adaptive Streaming, video content is temporally divided into multiple segments, each encoded at several quality levels. The client can adapt the requested video quality to network changes, generally resulting in a smoother playback. Unfortunately, live streaming solutions still often suffer from playout freezes and a large end-to-end delay. By reducing the segment duration, the client can use a smaller temporal buffer and respond even faster to network changes. However, since segments are requested subsequently, this approach is susceptible to high round-trip times. In this letter, we discuss the merits of an HTTP/2 push-based approach. We present the details of a measurement study on the available bandwidth in real 4G/LTE networks, and analyze the induced bit-rate overhead for HEVC-encoded video segments with a sub-second duration. Through an extensive evaluation with the generated video content, we show that the proposed approach results in a higher video quality (+7.5%) and a lower freeze time (−50.4%), and allows to reduce the live delay compared with traditional solutions over HTTP/1.1.

Abstract: QUIC (Quick UDP Internet Connection) is a new multiplexed and secure transport atop UDP, designed from the ground up and optimized for HTTP/2 semantics. While built with HTTP/2 as the primary application protocol, QUIC builds on decades of transport and security experience, and implements mechanisms that make it attractive as a modern general- purpose transport. QUIC provides multiplexing and flow control equivalent to HTTP/2, security equivalent to TLS, and connection semantics, reliability, and congestion control equivalent to TCP. This draft documents the early deployment of the QUIC protocol prior to standardization.

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.

Abstract: Tremendous effort has gone into the ongoing battle to make webpages load faster. This effort has culminated in new protocols (QUIC, SPDY, and HTTP/2) as well as novel content delivery mechanisms. In addition, companies like Google and SpeedCurve investigated how to measure "page load time" (PLT) in a way that captures human perception. In this paper we present Eyeorg [12], a platform for crowdsourcing web quality of experience measurements. Eyeorg overcomes the scaling and automation challenges of recruiting users and collecting consistent user-perceived quality measurements. We validate Eyeorg's capabilities via a set of 100 trusted participants. Next, we showcase its functionalities via three measurement campaigns, each involving 1,000 paid participants, to 1) study the quality of several PLT metrics, 2) compare HTTP/1.1 and HTTP/2 performance, and 3) assess the impact of online advertisements and ad blockers on user experience. We find that commonly used, and even novel and sophisticated PLT metrics fail to represent actual human perception of PLT, that the performance gains from HTTP/2 are imperceivable in some circumstances, and that not all ad blockers are created equal.