HA1 Task 1 Glossary

Pixel
Pixel stands for Picture Element, a pixel is a single point in a graphic image. These small little dots are what make up the images on computer displays. They are divided up in thousands or even millions of pixels. You cannot see the individual pixels, because they are so small. This is actually a good thing because most people prefer to look at smooth, clear images rather than blocky ones.

Resolution
Resolution means how sharp and clear an image is. It is used to describe monitors, printers and bit-mapped graphic images. For dot matrix and laser printers the resolution shows the number of dots per inch. For graphics monitors the screen resolution is the number of dots on the whole screen.

Screen Ratios
The screen ratio of an image is the ratio of width to height. In still camera photography the most common screen ratios are 4:3, 3:2.

Frame Rate 
This is the number of images photographed per second. The more frames recorded per second, the more accurately the motion is put onto the recording device.

Video Formats
These are two way different types of technology involved with video formats. These are containers and codecs.
Containers are sometimes called wrapper. It describe the structure of the file.
Codecs (short for coder/decoder) are used inside a container. A codec is a way of encoding audio or video into a stream of bytes.

Compression
Compression is when you make the size of the data smaller to save space or transmission time. For an example when you want to send large text or files either on their own or as a group, you can transmit these in a zip file which is a compressed format.
Graphic image file formats are usually designer to compress information as much as possible as these files can be very large. Sometimes graphic image compression can be 'lossy' which is where some information is permanently lost or loss/less where the information can restored.