WHITEPAPER
Compared to just using Adaptive Bit Rate technology and/or standard clients, ML/AI-based OTT video clients help ensure higher video quality including minimizing playback errors and start-up delays. Continuously growing numbers of edge CDN servers accommodating the most downloaded video content for a specific area can significantly reduce streaming latency. At the same time, a video streaming session’s high quality, delivered with significant bandwidth efficiency, is ensured by the streaming protocols, such as the adaptive HTTP over TCP which uses advanced congestion mechanism, as well as the smart QUIC protocol, which is built on top of UDP, significantly reducing the TCP latency caused by multiple handshakes. Enabled by the evolution of mobile networks, devices and video streaming technologies, the popularity of OTT video streaming applications among subscribers keeps growing. Due to this, operators are increasingly facing a challenge to ensure the users’ experience of demanding OTT video streaming applications at minimal operational costs. This paper shows how operators can achieve this by using Infovista’s OTT video streaming application testing. Metrics required to describe OTT video streaming quality and the challenges to determine these are presented. A pragmatic solution to cope with the challenges and well suited for drive testing scenarios is discussed. Insights on OTT video streaming quality evaluation Metrics required for testing user-perceived OTT video streaming quality As described in ETSI TR 103.488 (Guidelines on OTT Video Streaming; Service Quality Evaluation Procedures), a user’s perceived quality of an OTT video streaming session has three dimensions: waiting time, video playback (also called presentation) quality and retainability (Figure 1). Evaluating the performance of any OTT video streaming application requires determining all three dimensions and understanding the impacting factors for each. Each of these three dimensions of a user’s quality of experience is determined by different QoS parameters related to the video streaming session phases as defined by the user’s actions when using the OTT application.
Request videoclip
(Play, Autoplay)
(User stop)
Display duration reached / video end reached
User action
Request video URL and ID
Bu ering
Displaying
Streaming phases
Load multiple HTML contents
(Stop playing)
Videoend
Video preparation time
Pre-playout bu ering time
Video streaming quality
Video playout duration
Video access time
Video playout duration (if user stop)
Perceived retainability
User perceived quality
Perceived waiting time
Perceived video quality (video playback time)
Figure 1. Typical OTT video streaming session (ETSI TR 103.488, YouTube example).
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