iPlayer uncovered: What powers the BBC's epic creation?

In this exclusive in-depth talk with BBC iPlayer boss Anthony Rose, CNET UK goes behind the scenes of the online TV service to discover what powers it -- and what's next

During peak hours, BBC iPlayer pumps out 12GB of data every second, and seven petabytes of data every month. It's insanely popular on Apple's iPhone -- but mostly after midnight -- and the next version of iPlayer will land this year, with some exciting new features.

These are just some of the fascinating facts revealed by iPlayer boss Anthony Rose, in an exclusive one-on-one interview with CNET UK.

Rose's official job title is Controller, Vision and Online Media Group, and he heads up many of the Big British Castle's Internet activities, including the BBC homepage and the site's search system, as well as iPlayer. Previously, he was chief technology officer at the file-sharing service Kazaa -- the music download service developed by the founders of Skype.

From what to expect over the next year of development, to a detailed look at the iPlayer's hardware, infrastructure and operation, this detailed interview takes you behind the scenes of the Beeb's enormous on-demand video service. 

What will iPlayer 3.0 bring later this year?

"At the moment we've got the Web site -- you go there and click play or you click download. But imagine a future where things come to you, where you can subscribe to things and have favourites and so on. Users are clearly telling us they'd like alerts and an online library, and having delivered HD and video quality that for the most part is similar in quality to TV, we now turn our attention to the personalisation and socialisation, and customisation of iPlayer.

"Although at the moment (iPlayer Desktop) is just a download system, in due course it's going to grow to become more part of the Web site. You'll be able to optionally log in to get enhanced iPlayer services: pre-booking, the equivalent of series link, and you'll be able to see which programmes you're subscribed to for automatic download." 

How much data is iPlayer really using?

"iPlayer usage on the iPhone is very popular and it's growing strongly month on month. Here's a fun stat: iPlayer usage, for streaming, peaks about 10pm –- just a little later from TV. But interestingly, iPlayer on the iPhone peaks at about midnight. So people are clearly going to bed with their iPhone and watching in bed. And we also see on the weekends, there's a peak of Saturday and Sunday morning usage at about 8 to 10am in the morning on iPhone.

Anthony Rose

"I think that at the moment, just for streaming, iPlayer uses about 60Gbps of bandwidth (that's about 7.5GB downloaded every second) in an evening peak. I think about 15Gbps for downloads, and about 1.5Gbps for iPhone. So overall on a particular peak day we may hit 100Gbps (about 12.5 gigabytes per second) although typically it'll be somewhat less than that. That turns out to be up to 7PB of data transfer a month.

"Petabytes is a nice number. Some people know about gigabytes, some know about terabytes, and then there's petabytes." 

Why did you abandon P2P downloads?

"I think the Internet world has changed in about the three years between our making a decision to use P2P and now. The P2P proposition was made in the day a long, long time ago, when distribution costs were really, really high, and it was felt that our servers wouldn't be able to cope with the load of a lot of people downloading.

"But in the end, what's happened is that streaming is clearly the main proposition, and download is about 10 per cent of the total consumption. So if the downloads came directly from our servers, it would add only a small extra on to the streaming piece, and in fact it made it more effective -- essentially more cost-effective -- to simply have a direct HTTP download of the download files, rather than maintaining the infrastructure for a separate P2P delivery network.

"Additionally, some people didn't like their upload bandwidth being used. It was clearly a concern for us, and we want to make sure that everyone is happy, unequivocally, using iPlayer.

"P2P did work very well for us, but times change and our saying we're not using P2P now, doesn't mean we will never want to use it again. We may find, for instance, that we use multicast for live video, or a live P2P in the future. The one thing that's constant in the tech world is that things change, and as of today direct download makes the most sense for us. But things may change in the future." 

Is the iPlayer completely automated?

"Most content these days is ultimately on tape delivery, so BBC Vision might have filmed a programme a year ago, or someone may have sent in footage, and it's often on tape. We will create a programme and it'll be saved on a digital tape, stored in a secure vault. Then a couple of days before a programme goes out on TV, that tape is ingested and turned into a high-quality 50-100Mbps video file. So there there's a lot of manual handling of tapes.

"Above the surface you see a Web site that's clearly computer-generated and automated, but beneath the surface there are some trucks driving around town with tapes. And we've been doing it this way since 1940 or earlier. There are a lot of systems which are operationally robust, but in a way a lot of Web people would consider legacy methods.

"There's an operational team of probably five people who make sure that videos get encoded, and there are about a dozen people who work on the iPlayer Web site itself and the content management systems that power it. There's also about a dozen people who work on the video player and the media production systems."

Next: The nuts and bolts...

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