QoE vs. QoS in Live and On-Demand Streaming
How do you define Quality of Experience (QoE) and Quality of Service (QoS) in live and on-demand streaming, and what are the key metrics for measuring them? IMAX’s Abdul Rehman, YouTube’s Sean McCarthy, SVTA’s Jason Thibeault, and PADEM Media Group’s Allan McLennan discuss these topics in this clip from Streaming Media Connect 2024.
The importance of human visual experiences
McLennan asks Rehman how he defines QoE and QoS.
“At the end of the day, what matters is what the human visual system is experiencing,” Rehman says. “What the human is getting on the other side of the streaming platform, whether it's a live or a file-based platform. That includes a number of elements that come together in making that experience. You obviously have the content creation part. You have the content delivery part in terms of whether there are enough bits in the right order and sequence in the right format, getting [it all] there to the device that is playing it, which is what we typically call Quality of Service in my view. And then you have the actual pixels that are being put on the screen and the device is behaving as expected and representing IMAX as intended. And that, as perceived by a human on the other side, is the viewer's experience. So in my view, that final experience that a human is perceiving at the satisfaction level that encompasses all of the above is the QoE.”
QoE measures the viewer's perception, while QoS involves network performance metrics
Thibeault agrees with Rehman that QoE is a measurement of how people perceive their video-watching experience. Regarding QoS, he says that it is “Definitely something that is more related to specific metrics [or] KPIs that you're setting for how the network performs and delivering that experience and then measuring against that expected level of performance.”
How live streaming has more QoS elements and potential breaking points
McLennan wonders what the key differences are for QoS and QoE between live and on-demand viewing experiences. He asks McCarthy, “You're dealing with YouTube right now, and so in this particular instance, what's your opinion about that?”
“It's a good question,” McCarthy says. “The QoE metrics that we measure from an end user perspective are more or less the same, but in a live workflow, there are more QoS elements and more potential breaking points, and therefore, I think it's more important to measure in real-time. At YouTube, which obviously is a majority VOD platform, I am focused on signal acquisition and live OTT. So, that is always the angle that I'll take when talking about QoS. What types of metrics matter to us? How do we think about the end-to-end signal chain? It's always in the context of a live workflow.”
He says that VOD workflows rely more heavily on perceptual quality metrics. “A: because it's easier to compute, and B: there's a lot more creative intent in a Hollywood movie than a sports production [where] you want to maintain the integrity of the pixels and the way that they're displayed on your screens and devices. And I think right now there's a trend in the industry to bring that same level of rigor of the actual bit flow and pixel quality monitoring to the live workflows.”
Join us in February 2025 for more thought leadership, actionable insights, and lively debate at Streaming Media Connect.
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