Several months ago, Eurofins Digital Testing said that it would work with Akamai to look at OTT quality of experience. Now, Akamai has said that based on the research, it believes that for good quality viewing of complex content on large screen TVs, 6-8 Mbps is needed, although for simple content (i.e. not sports or action footage), 2-4 Mbps is enough. A level of 2-3 Mbps is enough to deliver good quality content on smartphones.
The study looked at different types of content, ranging from basic talking-head footage to complex underwater shots, as viewed on different smartphones, set-top boxes, desktop PCs, tablets and smart TVs. Researchers used SSIMplus – an objective full-reference perceptual video quality-of-experience (QoE) index – in order to rank the perceived quality of the video, where anything rating above 80 out of 100 is deemed ‘excellent’- or the equivalent of HDTV. Across device types, the bitrate required to achieve an ‘excellent’ score varied considerably. When examining the relationship between delivery, player technology and content, Akamai also found that consistency of throughput was a key element to improving KPIs such as stream buffering.
“Due to the variable nature of player technology across such a wide and diverse device landscape , the ability to deliver a stream with consistent throughput, at any bitrate, is critical to ensuring the highest quality viewing experience. By managing the strategic relationship between content, delivery and devices, it’s possible to improve the quality of experience and reduce buffering significantly.”
explained Ian Munford, Director of Product Marketing in EMEA for Akamai.
The study, showed that optimal stream rates outlined in the study can be achieved across most mature markets to a high percentage of the population.
Munford continued:
“As the OTT market matures, Quality of Experience metrics need to evolve to include visual quality as well as the typical KPIs such as stream buffering and start-up time. This research shines a light on the role of perceptual quality and we hope to help broadcasters better understand ‘what good looks like’ as well as highlighting savings that they could realise by eliminating bitrate profiles that could be unnecessary.”
The study used SSIMPlus as an objective method of quality checking. Click for higher resolution
