I took a look at that old YouTube video and I see what you're saying about the integration of a MediaFirst-powered STB. Here is a press release issued by Arris in Feb. 2018.
ARRIS Next-Generation Set-Top to Power Tomorrow's TV for Bell Canada
ARRIS is enabling Bell, Canada's leading TV provider and largest communications company, to offer its Fibe TV customers an even more rich and personalized next-generation television experience with ARRIS set-top technology.
Bell's deployment of Ericsson's MediaFirst platform will deliver a lifelike 4K HDR experience with unmatched sharpness and clarity. MediaFirst delivers personalized Multiscreen, TV Everywhere, IPTV and Pay TV services and ARRIS set-top technology is at the heart of this next-generation system, featuring the latest 4K HDR capabilities, fast 802.11ac and 4x4 Wi-Fi.
"ARRIS is a trusted Bell partner in supporting our delivery of the future of TV," said Rizwan Jamal, President of Bell Residential Services and Small Business. "Fibe TV became Canada's #1 TV service by offering an outstanding viewing experience that's both personalized and on-demand. Together with ARRIS, we look forward to taking Fibe TV to the next level as we deliver the latest 4K experience to our customers."
"We are proud to be the launch partner for Bell's implementation of MediaFirst for Fibe TV, a fast-growing IPTV service with more than 1.5 million customers in Canada," said Larry Robinson, President of ARRIS CPE. "This deployment further demonstrates that ARRIS is the leading technology provider when it comes to enabling ground-breaking television services."
The ARRIS Global Services team will provide integration services and customization for the user experience.
This STB project could still be underway - they take time. For example, it took Rogers about 18 months from the time they announced the Comcast decision to the live rollout. By that time the software had been well-proven at Comcast and at Shaw Cable in western Canada. I'm not sure how mature the MediaFirst STB software is and how many large TV providers are using it.