Video's are made using avideo camera. Acamera is anelectronic device that takeslight from the real world and makes it into electric signals. A video camera is one that takes many pictures very fast to make it a video. Several video sequences may beedited together to make a presentation.
Video is shown with a screen. A screen can be amonitor, aprojector, or atelevision. The purpose of a screen is to turn video information into light.
Digital video came after analog video. At first, the digital video was not useful because thebitrate (how quick a picture moves through awire) was too high. Afterdata compression was made, digital video became more useful than analog video.
Frames per second is a number which means how quick a picture is shown to a person watching the video. Videos are just pictures shown one by one, but very very fast. So the frame rate is the number of pictures that are shown in 1 second.
A video can be interlaced or progressive. When a picture is shown in a video, it is divided into many lines.
In a progressive video, Thescreen will draw each line one by one from the top of the picture until the bottom of the picture.
But in an interlaced video, the screen will only draw theodd lines at first. So the screen will draw 1, 3, 5, 7, until it touches the bottom. When it does, the screen will go to the second line, and draw theeven lines.
Different kinds of aspect ratio. When the left number is bigger, the video becomes longer.
A video has anaspect ratio. An aspect ratio gives theshape of a video. The video can either be asquare or arectangle. To get the aspect ratio, you divide the width by the height. Then you write it as aratio.
A video shaped like a square has an aspect ratio of 1, because thewidth andheight are the same number.
A video which is a rectangle has an aspect ratio that is not 1. A video that is tall has an aspect ratio where the right side of the ratio is bigger. But a video that is wide has an aspect ratio where the left number is bigger.
The pictures in a video have color information. For everypixel in the picture, which is a small box which is part of the picture, there is a color. This color can be put inside the video using acolor model
