By: Catyana Brown

Information Technology in a Global Society: Multimedia

aka raster graphics◦ images that are composed of a rectangle of small dots

higher number of pixels = better resolution

Bitmap Graphics

Left: 8 mp Right: 5 mp

Resolution◦ number of pixels in the grid

◦ 1 megapixel = 1 million pixels

◦ Resolution on different screens are different screens are gauged by pixels per inch Pixels per inch (PPI) : determines how many pixels are displayed in each inch of the output Dots per inch (DPI) : aka printer resolution – refers to the number of ink dots that a printer produces

when creating an image

Bit Depth◦ aka color depth

◦ refers to the number of bits used to store each pixel

◦ higher bit depth = more color

Image Storage

Resolution & Bit Depth Storage Requirements

Desktop Computers

640 x 480 Video Graphics Array (VGA)

800 x 600 Super Video Graphics Array (SVGA)

1024 x 768 Extended Video Graphics Array (XGA)

1280 x 1024 Super Extended Video Graphics Array

1600 x 1200 Ultra Extended Video Graphics Array

Laptop Computers

1280 x 800 Wide Extended Graphic Array (WGA)

1440 x 900 Wide Extended Graphic Array (WXGA+)

Mobile Phones

120 x 160 Common on older phones

540 x 960 Common on newer phones

Televisions

1280 x 720 720p High Definition

1920 x 1080 1080p High Definition (Full HD)

Width x height x bit depth

Cntd.

Bit Depth

Maximum number of colors Storage required per pixel

1 2 1 bit (1/8 byte)

2 4 2 bits (1/4 byte)

4 16 4 bits (1/2 byte)

8 256 1 byte

16 65,536 2 bytes

24 16,777,216 3 bytes

32 4,294,967,296 4 bytes

Cropping◦ taking a subsection of a photograph and removing everything else

Scaling◦ increasing or reducing the size of a image

Cloning◦ the process of copying one part of an image into another part of an image

Layers◦ commonly used when making composite images

◦ allows several images to be ‘stacked’ on top of one another

Digital Manipulations

Filters◦ changes the contrast and saturation levels

◦ enhance the presence of certain colors

Composite Image◦ editing tools are used to combine two or more images

continued.

reduce redundant, repeated data in imagesLossless compression◦ looks for repeated patterns of data and stores them in a manner

which requires less space Also allows the original to be restored

Lossy Compression◦sacrifices image quality for reduced file size

Compression

aka object oriented graphics◦ composed of objects rather than pixels

◦ can be scaled as large as needed without loss of quality

◦ Ex: clipart photos

Vector Graphics

Bitmap Graphics Vector Graphics

Store data grids of pixels Store data as mathematical

Zooming in reduces quality No quality loss when zooming in

Increasing size reduces quality Can easily be resized with no loss of quality

Has lower processor requirements, but high memory requirements for large images

Requires a fast computer to manipulate complex graphics

Images consume lots of storage space

Images consume less storage space

Perfect for taking photographs Not possible to recreate complex real life scenes (ex. Photographs)

Musical Instrument Digital Interface (MIDI)◦ communication standard for music devices, computers, and music

creation software

Codec◦ a piece of software which tells media players how to decode the

particular compression format used by that video or audio data

Digital Audio