Akamai claims 6Mbps enough to achieve ‘excellent’ viewer rating for sport on TV

Cloud delivery platform provider, Akamai, recently released initial findings from research into the requirements for optimal viewing experiences across a range of devices. The research, conducted in association with Eurofins, provided guidance into what is an optimal video stream across a range of different content genres, devices and network conditions.

Findings show that delivering complex content such as sport or high action onto a large screen TV requires a minimum of 6Mbps to achieve an ‘excellent’ viewer rating, while smartphones require between 2Mbps to 3Mbps. For less complex content, optimal bit rates are lower and 2Mbps to 4Mbps will still deliver an excellent visual rating on large screen TVs. 

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 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 HD TV.  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,” said Ian Munford, director of product marketing, EMEA, at Akamai.  “By managing the strategic relationship between content, delivery and devices, it’s possible to improve the quality of experience and reduce buffering significantly.”

Ian Munford, director of product marketing, EMEA, at 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. On whether these minimums are regularly being served by cable, satellite and mobile network providers today, “Yes, they are,” stated Munford, pointing to fixed line connections, that are capable on the whole of receiving 8Mbps.

He also claimed that the minimum bitrates, enough to provide good quality HD, is enough. “People talk about 4K and HDR but the vast majority of content we seen being delivered is in the 3Mbps to 4Mbps range, way below HD, so it’s pointless talking about 4K when they aren’t even delivering HD.” He added that the lower bitrates of 2Mbps to 3Mbps are suitable for drama or talking heads, but for sport the minimum of 6Mbps is required to get a good perceptual quality.

“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 startup time,” continued Munford. “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.”