File Formats

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  • Created by: rbird123
  • Created on: 28-11-20 16:42

File Formats

Images 

Images can be stored in different ways on a computer. A drawing you create in PowerPoint is a vector graphic. 

It is made up of lines and shapes with specific properties such as line style, line colour, fill colour, start point and end point. 

When you take a photograph on a digital camera, the image is not made up of individual shapes. The picture somehow has to capture the continuously changing set of colours and shades that make up real-life view. To store this type of image on a computer, the image is broken down into very small elements called pixels. A pixel (short for picture element) is one specific colour.  

Resolution 

The size and or resolution  of an image is expressed directly as width in pixels e.g. 600 x 400. if the size of a picture is increased, then more pixels will need to be stored.

Videos 

As with images there are several different formats for video files. Avi developed by Microsoft , is one of the oldest video formats. 

MPEG4 is used for HTML5 videos and files usually have the extension .mp4. They can be played on Macs, PCs and iPhones.   

File Compression 

Image and video files are commonly compressed to create smaller files. With lossy compression, unnecessary information is removed from the file. Lossless compression retains all information so that the original file can be recreated exactly. 

Type

File Extension

Compression type

Explanation 

Bitmap

.bmp

Uncompressed still image file

Portable Network Graphic

.png

Lossless

16.7 million different

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