1. ITGS
Multimedia

2. Multimedia Multimedia Bitmap graphics (raster graphics)
Computer graphics, video, audio and interactive applications
Used extensively in entertainment, science and journalism
Bitmap graphics (raster graphics)
Images that are composed of a rectangle of small dots called pixels
Photographs are made up of pixels
Resolution
The higher the number of pixels in an image, the more detail the image can hold.

3. Bitmap Graphics Image editors Editing tools
Used to improve the appearance of a photo (Adobe Photoshop)
Editing tools
Cropping - taking a subsection of a photograph and removing everything else
Scaling - increasing or reducing the size of an image
Cloning - the process of copying one part of an image into another part of an image
Selection tools - very useful for highlighting just part of an image so that alterations are applied to only that area instead of the whole image
Layers - commonly used when making composite images
They allow several images to be stacked on top of eachother
Filters - effects features
Composite image - when editing tools are used to combine tow or more images
Computer generated imagery - (CGI) - a combination of photographs and computer-generated images

4. Social Impacts Social impacts Legal impacts Political impacts
It has become harder to detect alterations as editing software and techniques become more sophisticated
Health and Leisure
Altering the appearance of models to make them conform to a more stereotypical image of attractiveness
This creates unhealthy eating practices and negative body images in young people
Legal impacts
1994, O.J. Simpson case
Simpson’s defense lawyer complained that a pair of rare, expensive shoes whose prints had been found at the crime scene were photoshopped into another photo of Simpson (wearing them)
TIME magazine ran a photo of his mugshot which was digitally darkened to make him look more sinister
Political impacts
2004 Presidential election - a magazine combined two photos

5. Scientific Impacts Scientific impacts Spotting digital fakes
together - one of John Kerry in the 70’s and one of Jane Fonda at a protest of the Vietnam War
The public believed the photo, but it was a composite
Other examples of composite photos made to make situations look more dramatic
Scientific impacts
South Korean researcher Dr. Hwang Woo Suk resigned from his position at Seoul National University after allegations that he faked images showing research results
He digitally altered images to show 11 stem cell colonies, when there were only 3
Spotting digital fakes
The use of copy and paste and cloning tools often leaves tell-tale patterns of repeated pixels in an image
When not clearly perceptible, they can be detected by special photographic analysis software
It scans images looking for regions of similar color and content - the greater the similarity between 2 regions of an image, the greater the chance of manipulation

6. Image Storage Image Storage Bit Depth or Color Depth
Lighting inconsistencies can also be detected
Image Storage
All bitmap images are stored in the computer as a rectangular grid of pixels
Resolution - refers to number of pixels in the grid
Higher resolution - more detail can be stored in the image
Manufacturers of digital cameras quote the resolution in megapixels - the total number of pixels in the image, by the millions
Anything above 8 megapixels is good
Computer screens have a lower number of pixels per inch than cameras
Bit Depth or Color Depth
The number of bits used to store each pixel in the image
The higher the bit depth, the more colors an image can contain, but the more storage space it will require

7. Bit depth Storage requirements Compression
True color
The most common bit depth for photographs
3 bytes of storage are used for each pixel
In each pixel, 1 byte = red, 1 = green, 1 = blue
Storage requirements
Width x height x bit depth = storage requirement
Compression
Most file formats use some form of compression to reduce redundant, repeated data in images and reduce the amount of storage required
Lossless Compression
Looks for repeated patterns of data and stores them in a manner which requires less space, but it still allows the original data to be exactly restored

8. Lossless Compression
All bitmap images are composed of grids of pixels (left)
Each pixel represents a binary color value for the computer to display (right)

9. Lossless compression The values on the left represent each pixel value
On the right, the data is compressed to tell the computer that there are 8 pixels with the value 0 (blue), etc.

10. Lossy compression Lossy format: jpeg; Lossless = tiff
Problems with Lossless Compression
Lossless compression is less effective at compressing photographs, because they have a large variety of subtle shades rather than solid blocks of color
Lossy Compression
Sacrifices image quality in return for storage space
It discards data that ‘probably’ won’t be missed by the viewer
For example, if two adjacent pixels are almost the same color in an image, lossy compression might make them exactly the same
Problem: once data has been discarded, it cannot be retrieved again, so quality loss is permanent
Repeatedly editing an image, saving in a lossy format, editing and sving again will result in a gradual loss of quality at each save
Lossy format: jpeg; Lossless = tiff

11. PPI and DPI
Pixels per inch - how many pixels are displayed in each output, whether on screen or on paper
This determines the physical size of the output and how sharp it will be
Most computer screens are 96 PPI
Most commercial and professional printers require images that are 300 PPI
Dots per inch - printer resolution - the number of ink dots that a printer produces when creating an image
Printers only have CMYK (cyan, magenta, yellow and black) ink colors, so to produce all possibly colors, they mix inks in the same spot on the paper

12. Vector Graphics
Vector graphics - composed of objects rather than pixels (object-oriented graphics)
Each object is stored as a series of mathematical equations that define its starting point, ending point, and path, along with info about color and style
All objects remain separate in the image, so they can be edited, scaled, repositioned and recolored independently at any time
Most software supports only bitmapped images, so vector editors can usually export images in bitmap formats
Advantage: because they are defined mathematically, vector images can be scaled as large as required without any loss of quality
Disadvantage: because they are so complex, vector graphics require computers with faster processors to perform the number of calculations necessary

13. 3D Vector Images
3D Vector Images - Vectors are the primary method of creating three dimensional imagery
CAD - software used by architects and engineers to create 3D technical drawings of products in development
It can be viewed in detail before it is even created
It enables them to test physical properties such as weight, strength and material
Graphics in the Movies
CGI (computer generated imagery) is often used to create animations or special effects
Motion capture - the actor wears a special suit with markers at key points such as hands, arms, legs, head. As he/she moves, the markers can be detected by a camera connected to the computer, allowing it to know the position of the main parts of the body and build up a wireframe skeleton inside the computer

14. Movie graphics
Textures - it’s impossible to create the required level of detail purely with 3D vectors, so the overall shape of objects is modelled using a simple 3D shape and then a 2D bitmap texture is applied to give a deeper and more life-like appearance
Rendering or ray tracing - after properties such as reflections and light are added, the scene can be rendered to calculate how the light in a scene behaves bouncing off objects and into the virtual camera. Producing such high quality images for film and television can take hours for a single image, even on very fast computers.
Render farms - hundreds or thousands of computers working together to improve processing speed for this type of entertainment

15. Common video formats AVI - Audio Video Interleave
Lossy; early video format
MOV
Used in Apple’s quick time system
MP4-Motion Pictures Expert Group 4
New file format; more efficient lossy compression
WMV-Windows Media Video
Microsoft proprietary; supported on Windows

16. Common audio formats AAC-Advanced Audio Coding
Apple iTunes; lossy compression, supports DRM
FLAC-free lossless audio codec
Open file format, lossless
MP3-MPEG Audio Layer 3
Lossy format; the format that changed the music industry in the 90s
WAV - Wave
Common, supported by all audio hardware and software
WMA
Windows only; lossy, can be streamed

17. Common image formats BMP-Bitmap image TIFF-tagged image file format
Windows Paint Only
TIFF-tagged image file format
Lossless; used in professional printing
GIF-Graphics Interchange Format
Common on the web; supports transparency
PNG- Portable Network Graphics
Lossless, open format, supported by most browsers
JPEG-Joint Photographic Experts Group
Most common lossy file format; produced by all digital cameras; common on web

18. Common image formats PSD-Photoshop Document RAW-raw image
Photoshop proprietary
RAW-raw image
Raw image formats produced by digital SLR cameras. They maintain more color info than JPEG files and include metadata such as shutter speed and aperture.
SVG-Scalable Vector Graphics
Format for storing vector graphics; actually XML test files, meaning they can be edited in normal text editors

19. Digital Audio
Sounds and music projects are now produced entirely digitally
Sound is recorded, converted into digital data (digitized) - and loaded into audio editing software, where it can be manipulated using a wide range of effects and filters
Most audio editing software represents sounds graphically as waves, and allows sections to be selected, cut, pasted and moved freely
Sample rate or sampling frequency - determines the quality of a recorded sound
Analog data captured by a microphone must be converted into digital data for the computer to process
Sample rate determines how many times each second a digital sample of the analog data is taken
More frequent samples means the digital sound will be closer to the original
CDs are high in sampling quality = 44,100 Hz

20. Bit rate
Bit rate - a value displayed in some music players; the amount of data used to represent each second of audio
Higher bit rate = larger number of digital values to choose from when taking a sample
MIDI - Musical Instrument Digital Interface -communication standard for music devices, computers, and music creation software
MIDI devices have built-in recordings of different instruments played at different notes and pitches
MIDI music files contain only the instructions for how to play the instruments, not the actual sound
Digital Video
Moderately advanced video editing software allows the editor to add several video and audio tracks to allow smooth fades between videos and to provide separate audio layers such as dialog, music and background sound
Chroma key - (green or blue screen) effects allow part of a video image to be replaced with another image or video source by removing specific colors
Morphing - a source image is slowly transformed into a second image over a series of frames

21. Codecs
Codecs-needed to play compressed audio or video data on a computer
(compressor decompressor) is a piece of software which tells media players how to decode the particular compression format used by that video or audio data
Streaming media - video or audio that is played while it is being downloaded from the internet
Streaming media systems download a small part of the media into a buffer, which is played while another section is downloaded and loaded into the buffer
Intellectual property
Refers to non-physical creations such as stories, music, works of art and computer software
Copyright law provides protection against use of this intellectual property by unauthorized users
Copyright is automatically obtained by the author of a work when it is created - there is no registration or application process involved
Intellectual property refers to the work or idea itself, not the physical media containing it
Example: making a film adaptation of a book is a breach of copyright

22. Fair Use Fair use Enforcing copyright Free licenses Citing Sources
Some countries allow exceptions to copyright laws under certain limited circumstances
Purpose is important
Educational fair use: can’t copy full copies of a whole book
Impact on the copyright holder: will he/she lose money?
Enforcing copyright
Watermarking - photographers and artists insert a semi-transparent image , such as a name or logo, into the piece that makes it hard to remove but still easy to view the image
Free licenses
Licensing your work freely for non-commercial use
Creative Commons - free licnesing for non-commercial purposes, requiring attribution
Citing Sources
Sources of material should be cited
Never assume everything on the internet is free from copyright