Watch Movies Online Guidance 6
Streaming technology has made listening to music or watching movies on the net as easy as turning on the radio or TV. Here's how the technology works.
The first music and movie files you may find over the internet were just short clips because you had to download the entire file before you could play it. At the moment, however, you may start playing the file as soon as the very first bytes begin to arrive... because of streaming.
This immediacy is possible because streaming does not send files over the internet the same because so many other files are sent. It uses an alternative protocol.
A protocol is a group of rules defining how two computers connect with each other and the way they send each other data.
Most data that is sent throughout the internet is first broken up into packets (small blocks of data). The packets are sent separately and are the rejoined at their destination to ensure that the receiver gets the whole file.
The sending of most data via the internet is governed by a set 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 look for errors.
If one packet gets damaged when downloading is being controlled by TCP, downloading will be suspended while that packet is resent. That way, in the event the download has been completed, you may be sure that you've got the entire data file.
Whenever you are streaming files, in contrast, 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 free new movie. But if everything froze very briefly while a lost packet was being resent, you probably would notice the interruption.
With streaming technology, you should not have to wait for files to be downloaded entirely before you can begin listening to audio or watching a video. You can listen to a concert on the additional side of the world in real time, make a video call or watch a movie just like on television.
Streaming video works in a similar way to streaming audio, except that the video must be separated into its separate audio and video components when it really is within the buffer in the RAM.
The server that holds the video for streaming may have a video capture expansion card which may 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 trick in order to avoid having to capture more data than it needs in order to make transmission easier.
When the camera used to record the video is stationary, ie, it's not panning, the amount of data created can be reduced. This will likely be done because all moving images are made up of a series of frames (still images) that change in rapid succession to provide the illusion of continuous movement. The rate will likely be 30 frames a second which gives the video a smooth look.
The compression system reduces the range 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 exactly what the background looks like.
As long as the camera remains yet, only the changes within 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 may also 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 will 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 can be output to your monitor and speakers so you can watch the film and hear the sound-track.
