Internet blog

Even if EastEnders has nearly finished when you start watching it online, you can press a button and watch it from the beginning

My name is Henry Webster and I'm an Executive Product Manager in Media Services at the BBC - it's my job to deliver our live video and audio content via IP (Internet Protocol), such as to BBC iPlayer and Connected TVs.

Today marks a major step in the evolution of BBC iPlayer with the launch of 'Live Restart'.

A first in the UK, 'Live Restart' enables audiences to rewind and restart live TV on BBC iPlayer without waiting for the programme to end.

So, if you're stuck in a traffic jam, or delayed on the tube and miss the critical start of your favourite BBC programme when you get in, with one click you can skip back to the beginning of that live programme.

Unlike your typical PVR, there is no need to have previously been watching or recording the show. Whenever you join, with one click, viewers can either restart the programme that they are currently watching, or scroll back to watch programmes from the previous two hours.

My team are continuously working away to deliver great innovations to audiences around video playback.

I'd like to highlight some of the work that has gone on behind the scenes to support this new way of watching television.

The technology that allows us to offer this new functionality is part of a wider strategic move to embrace HTTP chunked streaming for delivering our online video.

Instead of using a point-to-point streaming protocol such as RTMP as we have done in the past, this method breaks up the H.264 video into chunks and delivers them as HTTP packets in much the same way as the we deliver our text rich web pages today.

There are a number of reasons why we have taken this approach; firstly it allows us to scale our video operation to a much greater extent than we have been able to before.

We already use Content Delivery Networks (CDNs) to help us with video delivery, but a move to HTTP streaming means that instead of relying on their capacity to stream video from specialist video servers, we are now able to use their cheaper and more abundant HTTP serving capacity.

The increased capacity that we can realise this way means that we are more likely to be able to support the ever growing audiences that are turning to their IP connected devices to watch TV and listen to radio.

This is especially important in a year when we will be streaming more live video to more people than ever before with the Euro Football championships, Radio 1's Hackney Weekend, Wimbledon and the London 2012 Olympics, to name but a few key events.

In turn the improvement in distribution will also allow us to make quality improvements across the board.

The use of HTTP chunked streaming has enabled us to significantly improve the video experience by utilising advancements in adaptive bitrate playback.

This means that regardless of the bandwidth available to you locally you should get a largely uninterrupted video experience offering the very best quality video your connection can support.

The live restart functionality that we are launching on the iPlayer today is typical of the cool new interactive features that we can drive using HTTP streaming.

As we can keep all the video chunks as we distribute them, we can offer them to be viewed again later, or even store them more permanently.

This has the major advantage over most PVR type products in that you don't need to have planned your viewing in advance! If you walk in twenty minutes after the start of the latest episode of Silk, you can now with one click, jump back to the start of the programme. Try it for yourself.

To do this we have linked up the programme schedule data with a rewind-able live stream which means, where rights allow, that you should easily be able to navigate back to the start of the currently live programme, pause and resume a live stream or look back at anything that happened in the last two hours.

We are using the same behind-the-scenes technology to drive the new experiences we have in store for the Olympics in our exciting new Live Interactive Video Player. Gary Lineker can give you a quick guided tour, where you can see a sneak preview of what's in-store for the Olympics

These innovations have touched virtually every piece of our video over IP delivery chain and the move to HTTP streaming has been a challenging one as it has required us to completely re-think our distribution platform.

I must, therefore, take this opportunity to pass on my sincere thanks to all those who helped us pull this together from within the excellent team that we have within the BBC, but also from our partners at AtoS and Adobe with whom we have worked very closely to get to grips with the new technology and in designing and building everything that we are using to roll this out as a live service.

It's always great hear your feedback, so please try it out and let us know what you think.

Henry Webster is an Executive Product Manager in Media Services at BBC Future Media