Cable Forum - View Single Post - How Video On Demand Works (long and technical!)

Stuart · 13-06-2006, 21:58

Think of it this way. Have you ever watched a video clip from the BBC website? When you double click on them, your PC communicates with the server at the other end and requests that it start sending your video clip. In this way, it's like downloading the clip. Now, the major difference between streaming and downloading is that with streaming, the player downloads a very small section of the clip, then plays that, while downloading the next section in the background. It carries on like this until the clip is finished. That's basically the priniciple behind web streaming.

VOD uses the same priniciple (you select a programme, click, the STB then streams it in the same way as the video clip above), but you can pause it, rewind and fast forward the video as if you were watching it on tape.

The reason it is taking a long time is that NTL actually require an awful lot of hardware to make it work (mainly servers for the Set Top Boxes to stream from). The user will never see this hardware, so it's easy to think NTL is doing nothing, but the hardware is being installed at each headend (where your TV comes from)., and takes a while to install.

Note: STB = Set Top Box.

13-06-2006, 21:58	#56
Stuart - Join Date: Jun 2003 Location: Somewhere Services: Virgin for TV and Internet, BT for phone Posts: 26,546	Re: How Video On Demand Works (long and technical!) Think of it this way. Have you ever watched a video clip from the BBC website? When you double click on them, your PC communicates with the server at the other end and requests that it start sending your video clip. In this way, it's like downloading the clip. Now, the major difference between streaming and downloading is that with streaming, the player downloads a very small section of the clip, then plays that, while downloading the next section in the background. It carries on like this until the clip is finished. That's basically the priniciple behind web streaming. VOD uses the same priniciple (you select a programme, click, the STB then streams it in the same way as the video clip above), but you can pause it, rewind and fast forward the video as if you were watching it on tape. The reason it is taking a long time is that NTL actually require an awful lot of hardware to make it work (mainly servers for the Set Top Boxes to stream from). The user will never see this hardware, so it's easy to think NTL is doing nothing, but the hardware is being installed at each headend (where your TV comes from)., and takes a while to install. Note: STB = Set Top Box.