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Volume Two - Academic Conferences

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Paul Newbury et al.<br />

It is designed for high-bandwidth connections such as on-campus, but works well on good broadband<br />

connections. It is impossible to say what a good connection is due to broadband being sold at speeds<br />

‘up to’ a certain bit rate. However, if a speed-test reports a constant bit rate of over 2.5Mbits/sec, then<br />

a high-quality stream will play successfully.<br />

A low-quality stream is provided for slower connections, and also is often required during peek<br />

Internet access times when the contention ratio of some broadband users results in a low attainable<br />

bit rate.<br />

A mobile stream is provided for mobile devices – specifically iOS-based (iOS 2011) devices at<br />

present. A mobile website is driven from the same content management system as the desktop<br />

version, with video content being handled directly by the iOS video engine. A dedicated app has been<br />

developed that can be used instead of the mobile website. It is presently still in testing, with the<br />

intention of releasing for the start of the 2011/2012 academic year.<br />

2.3.1 Live delivery<br />

The live recording production method for the on-demand content opens up the possibility of live<br />

transmission of events. This results in programmes that look and feel the same as the recorded<br />

programs, but which are now transmitted in real time. This gives some additional advantages over<br />

recorded material. Firstly, it can be compelling to watch. Secondly, the audience is more forgiving of<br />

mistakes. Thirdly, it gives the online audience the ability to interact live from either the desktop web<br />

application, or an iOS device. Figure 8 shows a live presentation being given with a voting system in<br />

operation.<br />

Figure 8: Live presentation<br />

In order to transmit live, there is a small modification to the production system (see Figure 9). The<br />

Wowza streaming server is now fed with a single quality live h.264 RTMP stream targeted at playback<br />

in a Flash player. From this, the Wowza server then generates a second HTTP stream targeted at<br />

572

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