SES. S.A. says more than 15 cable operators are now testing its managed 4K/Ultra HD after adding a handful of additional MSOs to the mix.

The latest to ink UHD trial agreements include Aureon in Iowa, GVTC Communications in Texas, Highlands Cable Group in North Carolina, KPU Telecommunications in Alaska, Service Electric in Pennsylvania and New Jersey, and Shrewsbury Community Cable in Massachusetts.

Others announced trial partners include Armstrong, Buckeye Broadband, Cable America Missouri, Entouch Systems, Golden West Cablevision, Frontier Communications, KPU Telecommunications, MTC Cable, and Marquette Adams Communications.

RELATED: Frontier Joins SES 4K Trials

A “large tier 1” is also on board for a 4K trial, according to Steve Corda, VP of business development in North America for SES.

SES is delivering nine channels (see below for more details) for the 4K trials, with a tenth to be added soon, Corda said.

SES is using its managed satellite platform to get the 4K signals to its trial participants. Most of the cable operators that in the pilot are delivering the signals over QAM transport to set-top boxes, but some are also considering deliver over DOCSIS networks using IP multicast technology.

Corda acknowledged that the bandwidth required for 4K services and the trials have been a big concern to MVPDs from the get-go, so SES has focused on getting those signals to fit within an HEVC-encoded stream of about 18 Mbps. Boxes in the consumer’s home need an HEVC decoder to capture the signal and deliver it a 4K-capable TV.

18 Mbps was a key bit-rate target, he said, because cable operators stressed that it’s important that they can fit two 4K TV signals into a 6 MHz-wide channel. On SES’s end, that bit rate also enables the company to balance video quality and cost, while also allowing four UHD signals to fit into a satellite transponder, and up to 16 UHD channels to be re-multiplexed on a satellite receiver

Though SES’s 4K platform is still in trial mode, commercial readiness is a few weeks away, Corda estimated, adding that everything has reached a “tipping point.”

“The technology has clearly matured,” he said, noting that SES is making good progress on its plan to reduce the time for a 4K platform to go from trial to commercial in a period of about two years.

SES introduced its UHD solution for cable systems in April 2015, and kicked off its first trial in June 2016. Eight U.S. cable operators were on board by November 2016.

SES’s managed 4K offering currently offers nine channels: Fashion One 4K (reality shows, documentaries and entertainment news about fashion); Insight (reality, entertainment and sports content aimed at millennial audiences); Travelxp 4K (a travel channel dedicated to content in 4K and High Dynamic Range); Nature Relaxation (a nature channel produced in San Diego by film maker David Huting); C4K360 (extreme sports, drone races, dance and club music); 4K Universe (mix of movies, documentaries, and live sports); Nasa TV UHD; UHD1 (an SES-programmed channel); and SES Demo Channel (test video sequences that MVPDs can use to conduct technical assessments).