Year 10Digital Media

Digital Media

Analogue data – continuous waveform. The world we live in!

Digital data – exact quantity. Computers use binary data made up of 0 and 1.

Digital media consists of text, graphics, audio, animation and video.

This topic will look at storing, creating, editing and displaying each of the digital media.

Purpose of Digital Media

The analogue world we live in is in a digital revolution.

E-music – mp3’s and downloading from the internet. iTunes….YouTube

Digital newspapers – The stories are already in digital form. The

paper can be customised to the user (users name and layout). All the stories are provided as hyperlinks. Can search for stories and updated instantly.

Purpose of Digital Media

Interactive TV – Allows user to interact with the screen. The user may select camera angles or alternate outcomes. E.g. DVC

Games – more interactive, realistic characters, complex background sounds and greater attention to detail. Half Life 2 Trailer

Health – Doctors can perform operations to patients using digital virtual reality.

neuroArm robot performs brain surgery: A world first

Video – Brando Returns (SMH 15 July 2006)

Superman father, Jor-El, who – as in the classic 1978 movie – is played by Marlon Brando.

Marlon Brando died in 2004 but a team of 30 from a digital effects company revived him for the role.

Marlon Brando Example

Emerging Technology

For homework: Research a digital media product or company and create a PowerPoint report (10 slides maximum) on an emerging technology relating to that product.

Your report needs to contain a description of your chosen digital technology and also any relevant issues (legal, ethical, social, industrial)

Prepare a 5 Minute presentation and present this to the class.

Digital Media Products

DTP: Desktop Publishing

Newspapers Magazines Certificates Etc.

Graphics

Bit-Mapped graphics Uses pixels .bmp

Vector graphics Drawing programs Shapes and lines

Audio

Captured using a microphone A sequence Wav Mp3 Wma Aac

Midi

Uses notes http://www.youtube.com/watch?v=3IxGaIM2lZU

Musical Instrument Digital Interface 16 at once Easy to edit

Animation Sequence

Movement of objects

Path Based Cell Based

Swf Mov Gif

Video productions

Created using video clips Digital camera Video editing software

Video clips Audio Pictures Text Frames Transitions

Eg Windows Media Player

Homework

Exercise 11.1 page 242 – 243 Questions 1 - 4

Manipulation Techniques

The processing of digital data Involves using software to

manipulate each data type: Graphics Audio Animation Video

Graphic Manipulation

Cropping Resizing Size and position Rendering Colour Effects Special Effects

Audio Manipulation

Amplify Equalisers Stretch Noise Removal Delete Silence Echo Fading

Animation Manipulation

Tweening Morphing Warping

Video Manipulation

Trimming Splitting Combining Transitions Adding a picture Adding Audio Titles and Credit

Homework

Exercise 11.2 Questions 1 - 4

Digitalisation – Text pg249 Text is digitised using a standard method of conversion such as ASCII. Each character is assigned a decimal number and converted to binary code. Eg Page 370 - 371

A scanner creates digital data from any printed pages this is stored as an image and an Optical Character Recognition (OCR) software converts to an ASCII form.

Text entered through a keyboard is already in a digital form.

http://en.wikipedia.org/wiki/ASCII

ASCII American Standard Code for Information Interchange

Digitalisation – Graphics pg 249

Graphics use bit-mapping Pixels. Each pixel is assigned one or more bits The number of bits per pixel is called bit

depth (or colour depth). Resolution is the total number of pixels

on the screen. Colour and grayscale increase the

number of bits per pixel and increase the file size.

Digitalisation – Graphics pg250

To determine the file size of a graphic in kilobytes we use the followingFile size = Horizontal pixels x Vertical pixels x Bit depth (in KB)

8 x 1024 Calculate the file size in KB of a black and

white image (1 bit per pixel) with a resolution of 300 x 180

File size = 300 x 180 x 18 x 1024

= 6.59KB Calculate the file size in KB of a 250 by

192 graphic with 256 colours (8 bits per pixel) File size = 250 x 192 x 8

8 x 1024 = 46.88KB

Digitalisation – Audio pg 251

Sound is digitised by sampling. Sampling converts a sound wave to audio.

Three important characteristics called sampling rate, bit resolution and the number of channels.

Sampling rate – the number of times a sample (slice) is taken from the sound wave.

Bit resolution – number of bits per sample. Common size 8, 12 and 24 bit sounds.

Channels used by the sound. Mono uses one channel and stereo uses two channels.

Digitalisation - Audio

Table 11.2 Sampling rates and their uses P251 power

To determine the file size of audio in kilobytes we use the followingFile size = Sample rate x Bit resolution x Time(s) x Channels

8 x 1024

Calculate the file size in MB of an audio file that was sampled with 44.1kHz with 16-bit resolution and lasted for 3 minutes in stereo.

File size = 44 100 x 16 x 180 x 2

8 x 1024

= 31007.8 1KB

= 30.28 MB (divided by 1024)

Digitalisation – Video/Animation Video is made up frames that contain

individual images. Frame grabbing captures frames from

continuous analogue data. Frame rate is the speed of the video or

animation. It is measured in frames per second (fps)

Comparison frame rates 30 fps refresh rate of monitors 25 fps video speed for PAL system 24 fps film speed for motion pictures 12 fps cartoon animation speed 8 fps minimum speed for illusion of motion

Digitalisation – Video/Animation

To determine the file size of a graphic in kilobytes we use the following

File size = Frame rate x Time (s) x Horizontal pixels x Vertical pixels x Bit depth (in KB)

8 x 1024

Calculate the file size in GB of a 15 min video at 25fps. Each frame is 352 by 288 at 24 bits per pixel.File size = 25 x 900 x 352 x 288 x 24

8 x 1024= 6 682 500KB= 6.37GB (divided by 1 028 576)

Data Compression

Data compression reduces the number of bits required to represent the information.

Compression ratios compares the size of the files. 2:1 means the compressed file is half the original size.

Two common types are lossy and lossless. Lossless – repetitive patterns are coded, no

data is lost. Reduce file size by 3:1 (30%) Lossy – data discarded. Can reduce file size by

200:1 (95%)

Homework

Exercise 11.3 Page 253 Questions 1 - 5

Displaying Digital Media

Different devices are used to display digital media it depends on the media type.

Screen – provides immediate feedback. Can display text, graphics, animation and video data.

Printer – outputs a paper copy of data. Can display text and images by spraying very fine drops of ink on paper.

Speaker – device used to present sounds. Personal computers general have a small built in speaker. For high quality sounds, speakers and sound cards are needed.

Distribution of Digital Media Sharing the digital media with other people. Can distribute hard copies (on paper) or

software copies (optical disks, Internet and streaming).

Optical disk are storage mediums to distribute digital media. Can store large amounts of data. Examples are CDs and DVDs

Internet consists of websites. The sites display text, graphics, animation, audio and video.

Streaming is a method of displaying audio and video across a network. The streamed item is played within a few seconds but the data is not stored permanently on the computer.

Homework

Exercise 11.4 Page 257 – 258 Questions 1-4