Lecture 7: Audio Intro to IT

COSC1078 Introduction to Information Technology

Lecture 7

VideoJames Harland

james.harland@rmit.edu.au

Lecture 7: Video Intro to IT

Introduction to IT

1 Introduction

2 Images

3 Audio

4 Video

5 Computer Fundamentals Assignment 1, WebLearn Test 1

6 Computer Fundamentals

7 Computer Fundamentals

8 Operating Systems WebLearn Test 1

9 Operating Systems Assignment 2

10 Internet

11 Internet Security   WebLearn Test 3

12 Future of IT Assignment 3, Peer and Self Assessment

Lecture 6: Audio Intro to IT

Overview

Questions?

WebLearn Test 1

Video

Questions?

Lecture 6: Audio Intro to IT

Web Test 1

Now Week 5, not week 4 (so not this week)

Quizzes (practice tests) up later this week

Content will be on weeks 2-4

Images

Audio

Video

Lecture 5: Audio Intro to IT

Introduction

Who is this bloke?

Lecture 7: Video Intro to IT

Overview

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Lecture 7: Video Intro to IT

History – which came first?

Invented in 1920’s

Commercially available in 1930’s

Widespread in Australia in 1950’s Invented in 1940’s

Commercially available in 1960’s

Widespread in Australia in 1980’s

DOMINATES

STANDARDS

Lecture 7: Video Intro to IT

Video formats

NTSC National Television Systems Committee

North America, Japan, Taiwan, Caribbean, …

PAL Phase Alternating Line

Western Europe, Australia, New Zealand, Asia, …

SECAM Sequentiel Couleur avec Memoire

France, Russia, Eastern Europe, …

“TVs ain’t TVs!”

Lecture 7: Video Intro to IT

Cathode Ray Tube (CRT)

Before “flat screens” (both and )

Draws horizontal lines

Type Lines Visible

NTSC 525 480

PAL 625 576

SECAM 625 576

Lecture 7: Video Intro to IT

Cathode Ray Tube (CRT)

Top to bottom

One pass (progressive scan)

Top to bottom

Two passes (interlaced scan)

1st pass is even lines (lower field)

2nd pass is odd lines (upper field)

Can create discontinuities in slow replays

Lecture 7: Video Intro to IT

Cathode Ray Tube (CRT)

Overscan:

Not all the image is visible on the screen

Allows ‘fuzzy’ edges not to be seen

Means content cannot be placed at the very edges

Safe action area: centre 90%

Safe title area: centre 80%

Lecture 7: Video Intro to IT

Cathode Ray Tube (CRT)

Safe action area

Safe title area

Lecture 7: Video Intro to IT

Cathode Ray Tube (CRT)

Black and white: only needs luminance (what shade of grey?)

Colour: luminance + 2 x chrominance

(brightness, 2 x colour or hue)

WHY?

Lecture 7: Video Intro to IT

Cathode Ray Tube (CRT)

Black and white came first!

When colour transmission became possible, needed ability to receive colour with

Black and white: luminance onlyColour: luminance, hue, saturation

YUV used in PAL, YIQ used in NTSC (!!)Can convert RGB to/from YUV and YIQ (see material for formulae)

Lecture 7: Video Intro to IT

Sampling and Quantisation

Sampling As in image (resolution, or # pixels) As in audio, ie frames per second

Quantisation As for images, ie bit depth per pixel

Frame aspect ratio Viewing width to height

4:316:9

Lecture 7: Video Intro to IT

Pixel Aspect Ratio

NTSC DV frame is 720 x 480 pixels

720:480 = 3:2 ≠ 4:3 ≠ 16:9 (!!!)

DV frame scree

n

?????

Change pixel shape via pixel aspect ratio

Lecture 7: Video Intro to IT

Assignment 1

Use GIMP (or a similar tool) to perform some manipulations on an image

Address two issues in relation to this

Lab classes 2 and 3 based around GIMP

Main emphasis is on process, not result!

Is in the Learning Hub

SUBMIT VIA WEBLEARN

Lecture 7: Video Intro to IT

Assignment 1

Lecture 7: Video Intro to IT

Conclusion

Web Test next week (week 5)

Do online quizzes later this week

Keep reading! (book particularly)

Notes for Video in Learning Hub