Watching Movies Online 9
Streaming technology has made listening to music or watching see movies online (Read the Full Report) on the web as easy as turning on the radio or TV. Here is how the technology works.
The first music and movie files you can find online were just short clips because you had to download the entire file before you decide to could play it. In the present day, on the flip side, 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 won't send files over the internet the same because so many other files are sent. It uses a different protocol.
A protocol is a group of rules defining how two computers connect with each other and how they send each other data.
Most data which is sent throughout 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 in order that the receiver gets the entire 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 check 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, after the download has been completed, you can make sure that you've got the entire data file.
Whenever you are streaming files, on the contrary, UDP allows packets to get lost now and after that without interrupting the downloading. This really 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 may listen to a concert on the additional 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 has to be split into its separate audio and video components when it's within the buffer within the RAM.
The server that holds the video for streaming shall have a video capture expansion card that can capture either a live feed from a video camera or a pre-recorded video. The capture board turns the analogue signals it receives into digital data and compresses it.
At the same time, it employs a trick to prevent having to capture more data than it needs as a way to make transmission easier.
When the camera used to record the video is stationary, ie, it is not panning, the amount of data created may be reduced. This can 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 normally 30 frames a second which gives the video a smooth look.
The compression system lessens 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 still, only the changes in the frame, such as the movement of the actors, have to be transmitted. The background only has to be transmitted again after the camera starts to pan as well as 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's going to decompress them and load them into 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 movie and hear the sound-track.
