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Streaming technology has made listening to music or watching movies on the internet as easy as turning on the radio or TV. Here's how the technology works.

The very first music and movie files you can find on the web were just short clips because you had to download the entire file before you could play it. At this point, conversely, you may start playing the file as soon as the first bytes begin to arrive... as a result of streaming.

This immediacy is possible because streaming isn't going to send files online the same way because so many other files are sent. It uses an alternative protocol.

A protocol is a set of rules defining how two computers connect with each other and the way they send each other data.

Most data which is sent over the internet is first broken up into packets (small blocks of data). The packets are sent separately and also are the rejoined at their destination so that the receiver gets the whole file.

The sending of most data over the internet is governed by a group of rules called the Transmission Control Protocol (TCP). Streaming however uses the User Database Protocol (UDP).

These two protocols are quite different. The crucial difference is in how they check for errors.

If one packet gets damaged when downloading will be controlled by TCP, downloading will be suspended while that packet is resent. That way, after the download has been completed, you may be sure that you have the entire data file.

When you are streaming files, however, UDP allows packets to get lost now and after that without interrupting the downloading. This is fine because, when an occasional packet is lost, you are unlikely to notice any interruption to the music or movie. But if everything froze very briefly while a lost packet was being resent, you probably would notice the interruption.

With streaming technology, you do not have to wait for files to be downloaded entirely before you decide to can begin listening to audio or watching a video. You can listen to a concert on another side of the world in real time, make a video call or watch a film the same as on tv.

Streaming video works in a similar way to streaming audio, except that the video must be split into its separate audio and video components when it is within the buffer within the RAM.

The server that holds the video for streaming will have a video capture expansion card which will capture either a live feed from a video camera or possibly a pre-recorded video. The capture board turns the analogue signals it receives into digital data and compresses it.

At the exact same time, it employs a knockout post trick to prevent having to capture more data than it needs to be able to make transmission easier.

When the camera used to record the video is stationary, ie, it really is not panning, the total amount of data created can be reduced. This may be done because all moving images are made up of a series of frames (still images) that change in rapid succession to give the illusion of continuous movement. The rate is generally 30 frames a second which gives the video a smooth look.

The compression system lessens the number of frames needed by comparing adjacent frames and only taking account of pixels that change from one frame to another. It does this by establishing precisely what the background looks like.

As long as the camera remains however, only the changes in the frame, for example the movement of the actors, have to be transmitted. The background only must be transmitted again after the camera starts to pan and the background changes.

Video streaming will likely skip frames when your Internet link is slow, which may make the video jerky. Thus the faster your connection, the smoother the video will be.

When your computer receives the video signals, it shall decompress them and load them in to a small buffer in RAM as it does for audio.

At this point the signals are split into separate video and audio components that are sent to the video card and sound card respectively, whence they're output to your monitor and speakers so you may watch the film and hear the sound-track.