On-demand streams

Streams that are accessed on-demand, such as the BBC iPlayer TV streams, require there to be a 'back channel' from the user to the server so that commands, such as play, pause, stop etc can be sent back to the server to control the stream. Traditional broadcast systems don't have a back channel, so they're unable to deliver on-demand streams, whereas the Internet obviously allows interactivity.

On-demand content is expected to continue to grow over the next decade due to it freeing people from having to watch or listen to programmes according to the schedules, and it will be one of the factors that differentiates the Internet from the traditional broadcasting systems. The BBC, however, is working on adding iPlayer on-demand streams to Freesat and Freeview receivers, so owners of such receivers on these platforms will still be able to access on-demand content.