Today BBC iPlayer got a new feature called Live Restart which gives you the ability to rewind and restart live TV on BBC iPlayer without waiting for the programme to end.
If you are curious as to how the BBC have done this, this is what they posted on their blog today:
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.
I think this is really interesting, especially as it is, or rather was a real pain having to wait for the end of a program so you can actually start it! Well done BBC!