Multi-CDN Strategy Gives Us Options – Sky's Webb

Delivering video at high quality has always been a challenge, even over broadcast networks with spectrum dedicated to each signal, or via cable, where the network has capacity hardwired for each channel. But trying to deliver high quality of experience (QoE) for video consumers over the untamed, uncontrolled, wild west of the open Internet is a far more intimidating responsibility.

But that's what Sky's principal streaming architect, Jeff Webb, has signed up for. In an earlier interview, Webb discussed the need for high QoE, the balance between Sky's traditional and multi-screen services, and his offered thoughts on important developments in coming years. (See Sky's Webb on 'Closing the Gap'.)

In part II of the interview, he discusses key technology elements involved with high-quality online video streaming, such as CDNs, DRM and video compression.

Telco Transformation: What would you say are your biggest challenges today?

Jeff Webb: QoE -- it's the biggest challenge, and by a very long way. As a broadcaster, it's important that we offer the best QoE and it is consistent across screens and screen sizes. We're also concerned about DRM. As a pay-TV operator the content we deliver is expensive and difficult to produce, we must protect it. But we deliver to a variety of devices, so there are a lot of different flavors we have to consider -- Android, iOS, PlayStation and other consoles, TVs. There are some new standards, DASH, and common encryption, that can help simplify things for us, and will move the market over time.

The other aspect is how much control we have. Obviously we want to offer high-quality content with the best possible QoE. But for Internet streaming we can only control this up to a point. If the subscriber is on a Sky network [Sky is a triple-play provider in the UK; it also offers broadband] then capacity planning is in our hands, so there is a measure of control and we can deliver high-quality.

But for those off the Sky network, we have to work with their ISPs to ensure a good experience, in collaboration with them. Even though they are also our competitors [for broadband services]. Still, our customers are also their customers, so [both parties are incentivized] to deliver the best experience.

TT: You talked a little about your CDN options at TV Connect. Can we revisit that – what has been your approach to caching? (See Build or Buy: The CDN Dilemma.)

JW: One way to ensure QoE is to bring content closer to the customer. It cuts latency and reduces bandwidth requirements.

We decided to go with a multi-CDN approach. We have two CDNs, and we have expanded, and have built out our own CDN using Velocix. This gives us an additional benefit as we have redundancy [in case one CDN gets overwhelmed or fails]. But it also gives us options, as some CDNs are faster on some ISPs. [Based on each CDN's own peering relationships and caching nodes.] So it allows us to find the best, fastest ways to get content to customers and deliver the best QoE.

TT: Are there any new technologies or solutions in particular that you are looking at in the next year or so?

JW: Video compression is always important. There are two competing factors with video -- we want the best QoE, which means that we need a high bit rate. But not only does that cost more in terms of our content delivery costs, but it's also tough to get to the customer. For example, [UK regulator] Ofcom says that the standard connection in the UK is 10 Mbit/s, but that's not for everyone -- some people might have a lower connection speed. Also, even if the advertised rate for a connection is 10 Mbit/s, the network may not be able to actually deliver that bit-rate at a particular time. So video compression is critical.

We are starting to observe that the H.264 codec is running out of road. We've seen 20% year-over-year improvements in the past through software upgrades, we're not seeing that now. So we are now looking at HEVC, but it's not supported widely enough. My iPhone can't do it, at least not in the silicon. And to do it in software, it will run out of battery [far too fast.] But the next iPhone will probably be able to do it in hardware, and as penetration grows, we can look to HEVC.

We're using HEVC for Sky Q on the satellite service. We launched it last year, and wanted to offer 4K [to the set-top box]. We had to use HEVC, the bandwidth requirements would have been just too high otherwise. Now we are looking at an IP version of the box. Again, we'll need efficient compression for that, we'll have to use HEVC.

— Aditya Kishore, Practice Leader, Video Transformation, Telco Transformation