information processes and technology multimedia and graphics

Graphics and Multimedia

Multi-Media

• Multi Media describes several forms of media which combine to communicate more effectively than they would separately.

• Example –text and film Photos and Sound.

Why is Multimedia better than “Traditional Media”

• Traditional media could be defined as:

• Books /Magazines /Audio /Video

People would learn by:

Reading Books or Magazines

Watching TV or Movies

Listening to Audio

Or even a combination of several

Modern Multimedia

• Good Multimedia combines media elements to communicate MORE effectively than traditional media types

Characteristics of Multimedia that make it more effective in communicating

• It caters to different learning styles as some people learn better from listening, or seeing or reading.

• Good multimedia will combine these or let the user choose the form of instruction.

• Good multimedia will engage the user by letting them choose the topic or area of interest directly.

Cont.

• Multimedia allows learners to choose the level of difficulty that suits them best, unlike a book or a teacher who must teach to 1 audience.

• It allows learners to choose the pace of instruction –fast for strong learners, slow for those having difficulty.

• It allows the repeating of information as many times as necessary for learners having difficulty

Elements needed for good multimedia design

Consistency

Users expect that different applications will have a sameness to them which means knowledge is transferable to a similar product. Ie Disk symbol means save on most programs

• Also consistency is when buttons are in the same place from page to page or form to form.

Feedback

• Feedback describes elements that gives the user a response. Example: buttons clicked make noises. A progress bar showing how long until a process is completed.

Forgiveness

• High forgiveness allows users to undo mistakes or undo previous decisions in a program. All actions should be reversible.

Aesthetics

Aesthetics means its level of attractiveness. Good multimedia should:

• Have adequate amounts of whitespace (clean interface)• Not use too many fonts (confusing to reader)• Should not have overly bright or harsh colors (hurts

eyes)

Social and Ethical Issues

• Copyright

• Piracy

• Changing nature of work

Storyboards help us design and document Multimedia

The main theme

• The option topic is about how multimedia can be used to communicate more effectively in the area:

• Education /Training• Entertainment – Film and Television, Virtual Reality.• Business – Take a virtual tour of a house.• Emerging Technologies – LED TVs / 3D TV

» Digital TV» IPhones» Enhanced Reality

Vocabulary of Multimedia

• Enhance –to raise to a higher degree; intensify; magnify: Video and Audio enhanced the students learning

Synergy

• Synergy - the cooperative action of two or more elements for greater effect than either alone.

• Example: “The effect of Multimedia is one of synergy. Video and Text together create a more powerful learning/entertainment/business impact than each shown by themselves.”

Engage

• to occupy the attention or efforts of (a person or persons): “The video, voice narration and then interactive test engaged the student…”

Interact

• Interact: To act on each other

• Interactive multimedia means the user and program act upon the other. Both are active processes.

Vector Graphics

Vector graphics use mathematical

Formulas to store graphic data

This line might be stored as A3:F3

Only 2 points need to be remembered and stored on the HDD. When it is on

your screen however it must be displayed as pixels

Vector Graphics

• These coordinates or “vectors” are known as “primitives”. When stored on disk they are referred to as primitives as they are not formed yet.

Graphics & Multimedia

Vector graphics

• As co-ordinates only need to be remembered, less space is needed in storage.

• You can blow up pictures as large as required without distortion or loss of info

• Because of this it is perfect for plan diagrams such as blueprints, and technical specifications.

• It is the graphics used in Computer Aided Design or (CAD)

• Vector graphics can easily be changed.• If the program is called “*” Draw – It is a vector graphics

program. “*” Paint is bitmap

Frame Buffer

• The frame buffer or Video Ram is an area of very fast memory that contains the bitmap image of the current screen display

• Still pictures and movies must be displayed

Memory Chip

Frame buffer

Frame buffer or VRAM contains the bitmap image with the details of each pixel

Each pixel and its location needs to be stored on your HDD

Monitor mirrors exactly the contents of the frame buffer

The Frame Buffer and Image size

BIT DEPTH Relationships Number of Colors

1 2 2

2 2 4

3 2 8

4 2 16

8 2 256

16 (high color) 2 65536

24 (true color) 2 16777216

1

2

3

4

8

16

24

The Frame buffer and Image size

• Resolution is measured by the number of pixels per inch

Each Square is the same size but the one with the most dots has higher resolution

High Low

Resolution & Bitmaps

If you enlarge a bitmap image too much it pixelates or has jaggies

Jaggies or steps

Bitmaps distort and lose aspect ratio (relationship between the width and the height of an image ) unlike vector graphics

Anti-AliasingAnti-Aliasing is one of the most important techniques in making graphics and text easy to read and pleasing to the eye on-screen is anti-aliasing. Anti-aliasing is a cheaty way of getting round the low 72dpi resolution of the computer monitor and making objects appear as smooth

No Anti-Aliasing Anti-Aliasing

How it works

When the computer anti-aliases the line it works out how much of each in-between pixel would be covered by the diagonal line and draws that pixel as an intermediate shade between background and foreground

Dithering

Dithering

Dithering is the process of “mixing” pixels of two colors to create the illusion that a third color is present.

Full-color photographs may contain an almost infinite range of color values. Dithering is the most common means of reducing the color range of images down to the 256 (or fewer) colors seen in 8-bit GIF images.

Example: An image with only black and white in the color palette. By combining black and white pixels we can create grey

Dithering Examples

How to calculate image size

800 pixels

600 pixels

Bit plane is set At 24 bits

How to calculate the size• Calculate the number of pixels and Multiply pixels by bit depth / bit plane

600 x 800 x 24 = 11 520 000 bits

• Calculate the number of bytes by dividing total bits by 8

11 520 000 / 8 = 1440 000 bytes

• Calculate the number of kilobytes by dividing by 1024

1440 000 /1024 = 1406kb

Calculate the number of megabytes by dividing by 1024 since there are 1024 kb in a megabyte

1406 / 1024 = 1. 44mb (rounded up to the nearest mb)

800 pixels

600 pixels

Bit plane set at 24 bits

How to calculate the time needed to download or

upload the file USING A 56KB/S MODEM @ 200BITS PER SECOND

• Formula is Size of file / total amount transferred per second

600 x 800 x 24 = 11 520 000 bits

11 520 000 / 200 bits per sec= 57600 seconds (Number of seconds to transfer)

57600 / 60 seconds = 960 minutes

960 minutes / 60 minutes = 16 hours

800 pixels

600 pixels

Bit plane set at 24 bits

Things to think aboutWhy is file size important when designing your webpage?

Should you choose 16 bit color or 24 bit color?

How can we reduce the amount of memory required for graphics?

Reduce bit plane (Dithering Does this)

Reduce resolution of graphic thereby reducing the number of pixels

Video

Capture digital data from digital video camera

If it is an analogue camera, a video capture card is needed to sample the analogue data

Analogue capture card

Firewire card

USB

Digital movie file can now be edited

Charged coupled device (CCD) converts light into digital data or converts digital data into light

Codec

• Coder-decoder." A device or software application that converts analogue video and audio signals into a digital format for transmission. Also converts received digital signals

back into analogue format.

Analogue capture card

Firewire card

USB

Digital movie file can now be edited

Codec

Video Compression ExampleMpeg or Divx

• Frames are analysed and section of the frames are analysed.

• If sections within frames are the same such as a car coming down the road. Repeated elements such as trees are taken out. They are replaced upon decompression.

Video Compression

Large file sizes of video means compression is often used.

2 types of compression are:

Lossy – Data is lost or shed for the sake of file size. This may be bit depth ( number of colors) resolution, sound (stereo to mono)

Lossless – A type of compression that reduces data without shedding information- Example: A word document is compressed. Spaces are counted and then deleted. When uncompressed the spaces are put back. The number common vowels may be counted and then removed and then replaced by the program after decompression.

SamplingTo Sample: “To take portions from the whole to make a representative of the whole”

Illustration of Sampling

Analogue Soundwave

Digitally sampled Soundwave

How to sample a sound or digitally convert it from analogue to digital

COMPUTER

ADC DAC

MEMORY

MICROPHONE SPEAKER

000100100101101010101000

000100100101101010101000

Sampling

COMPUTER

ADC DAC

MEMORY

MICROPHONE SPEAKER

000100100101101010101000

000100100101101010101000

Real World Analogue signals are converted to “0”s and “1s”

Not all the sound information is recorded. Only important samples along the analogue wave.

What is useful? –Only what humans actually hear

Digital AudioThe type, size of the file and quality of digital audio

depends on 3 elements:

1. Frequency (11 khz, 22 khz or 44 khz)

2. Mono / Stereo

3. Resolution: bit size of the samplings

Summary

In general, the following rules apply:

Frequency – The higher the rate, the better the sampling quality

Mono/Stereo – 1 (mono) or 2 (Stereo) channels create depth of sound but needs more memory

Resolution – More bits sampled 8 vs 16 means greater accuracy

How to Calculate Digital File Sizing

Audio

video

Audio and video

Advantages of digitalised sound

Can be transported electronically or over a network (itunes)

Can be manipulated electronically I.e affects added

Can combine sounds and instruments to create a whole orchestra

Can be copied easily

DRM can be applied

Can be indexed and databased for access

Can be easily stored on hard drive and other media

Can be compressed

M.I.D.IMusical Instruments Digital Interface

MIDI (Musical Instrument Digital Interface, pronounced /ˈmɪdi/) is an industry-standard protocol that enables electronic musical instruments such as keyboard controllers, computers, and other electronic equipment to communicate, control, and synchronize with each other.

MIDI allows computers, synthesizers, MIDI controllers, sound cards, samplers and drum machines to control one another, and to exchange system data.

MIDI data files are very small and are often used as website background music

How to calculate size of uncompressed video

Calculate the size of a video file 10 seconds long at 5 frames per second, 50 pixels high and 50 pixels wide with a bit depth of 8bits. Express in bytes

5 frames x 10 sec x (50 x50 x 8 ) / 8 = total uncompressed size

Questions

Cell based animation

Cell based animation is when picture movement is drawn or created a little bit different each time. When viewed in quick succession it appears to move. This is the traditional method that Disney used on transparent pieces of cellulose, hence “cells”

•Each picture is a frame or a cell

•Each one is drawn individually and requires memory storage

Cel Based Animation Cont.

Notice the picture of the sun. Each frame consists of a background and a “sprite/s” that move

Path Based AnimationPath based animation relies on the computer program to do most of the work. The artist specifies the “path” for each moving object. Key points

are specified and then the program calculates what changes are needed between points

Bang

Key point

Key point

Key point

Sprite

Computer Fills the gaps between key points of the animation

Bang

Key point

Key point

Key pointSprites

Path Based Animation cont.

• This use of key points in which the computer generates everything that goes between points is also known as “tweening”.

Morphing

• Morphing is when 1 object changes to another. Example: A man turning into a lion

In this example, it is one person turning into another person

WarpingWarping should never be confused with Morphing. Warping is when the original image is distorted, and twisted about

Digital Rights Management

• Technology designed to prevent the copying and distribution of digital media.

Itunes. Prevents the moving of songs from one machine to the other.

Youtubes forthcoming digital fingerprinting.

Digital fingerprinting technology is when media is tagged so that if it is uploaded, it is instantly recognised as copyrighted material and automatically deleted.

Big pond movies – Media will only be playable for a given amount of time.

How MP3s Work

• MP3 algorithms compress a digital sound file to a much smaller size.

• Compression Algorithms are used to reduce the size of the file using “lossy”

• An compression algorithm is a set of instructions that process the sound file to reduce it using a set of criteria.

How it works

• To make a good compression algorithm for sound, a technique called perceptual noise shaping is used. It's "perceptual" partly because the MP3 format uses characteristics of the human ear to design the compression algorithm.

What the algorithm looks for to leave out or emphasise

• certain sounds that the human ear cannot hear.

• certain sounds that the human ear hears much better than others.

• If there are two sounds playing simultaneously, we hear the louder one but cannot hear the softer one.

MP3

• certain parts of a song can be eliminated without significantly hurting the quality of the song for the listener.

• Compressing the rest of the song with well-known compression techniques shrinks the song considerably -- by a factor of 10 at least. When you're done creating an MP3 file, what you have is a "near-CD-quality" song. The MP3 version of the song does not sound exactly the same as the original CD song because some of it has been removed.

How Film Compression works

• Files such as DivX, Mpeg and .AVI have been reduced using the following methods:

• Reduce the number of frames per second. • Reduce the sampling rate and size of the audio• Removing from the video parts of the image that were

already shown. Example: in a video where there is one person talking and that this person is not moving. On the first frame the image is shown complete, but on the second frame the parts of the image that are identical to the first frame are removed from the image. If only the mouth of the person is moving, only the area around the mouth will be drawn on the second frame.

Multimedia Types

• Text – includes words and numbers and special characters such as #@$.

• Hypertext / Hyperlink – Clickable text that links to a URL (universal Resource Locator) in the format of a www.domainname.com or file location.

• Hypermedia- Is clickable media other than text. Example: we can click on a photo or animated gif. It will link to a URL or file much the same way as a hyperlink.

• Streaming video – Video which is sent over a network using UDP protocols to be played on embedded video players on a browser.

• Whitespace – The area of a webpage left white. Too much clutter confuses the user and inhibits communication. The correct amount of whitespace will direct user focus.

New Technologies used to share information via Multimedia

• RSS – Real Simple Syndication is a method by which information is published to users to keep them updated. A user elects to accept a RSS feed in their browser.

• Share features like Digg allow user ratings of web content. Higher ratings result in a higher profile of the content in the Internet community. (User interactivity)

• Twitter – information and opinion sharing forum that played a prominent part in showing what happened in Iran this year.

• Youtube – Video Streaming

Convergence

• Convergence describes the coming together of technologies to form a new one that is more powerful in its ability to communicate.

• Example – Camera / Phone» Camera /Phone/Computer» Watch / GPS» Video camera /GPS