Live or progressive? Which codec and compression rate? All these factors and more impact end user QoE and operator’s bottom-line.
By 2020, more than half of all mobile data will be video driven, according to industry projections. As consumer demand for mobile video continues to explode, service providers have to deliver robust quality of experience in an increasingly complex landscape of mobile video.
Facebook, with more than 1 billion users, is evolving into a video-driven community and YouTube is a well-established, ever-growing stakeholder. Those two companies account for one-third of all data traffic. Factor in Pandora, Netflix, Instagram, iTunes and others, it’s challenging for service providers to maintain focus on QoE.
“All these things are really complicated delivery mechanisms,” Rob Wattenberg, product manager for Rohde & Schwarz, said, and they all “affect end-user quality of experience and we have to be able to find a way to test these things.”
Delivering QoE isn’t as simple as creating a high-capacity data pipe though. Consider a 4K video, which can require between 11 Mbps and 60 Mbps depending on codec, service, players and other factors; then there’s added complexity with live video and the variation between device size and function.
“All these things affect quality of experience, so it creates a pretty big technical challenge for network operators who really should be focused on quality of experience for the end users,” Wattenberg said.
When operators move to test different video-based network scenarios, important factors include real time or progressive download, digital video compression strategies, how a video is hosted, the importance of YouTube, specific metrics to gauge video performance and even video streaming as a means for network optimization.
“Do we want to look at video streaming as a means for network optimization?,” Wattenberg said. “As an end user, if I’m watching a video, I want to make sure I’m having a good experience, but how does that affect, or how does that influence how a network operator might optimize the network from an IP or even an RF perspective?”
Wattenberg and Jens Berger, Rohde & Schwarz head of applied research, discussed those questions and other aspects of video network testing in a recent webinar.
To a user watching a movie at the airport or a live football game on the bus, important determinants of video quality include visibility of details like sharp edges and fine structures, and fluent, continuous playback with no freezing or stalling—what they see on the screen.
“To measure visual quality,” Berger said, “We have to look at the picture itself.” One way to do that is to compare visual quality with a reference image. With live video orvideo telephony, distortions are analyzed. These tasks are complicated, among other reasons, because third-party service provider make technical changes regularly.
“Visual quality is the only integrative metric considering all influences on quality as human viewer[s] will perceive,” Berger continued. “Optimizing a network for real time delivery of video is the basis of all real time content delivery…as we go to connected cars and beyond to other future applications.”
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