U21A1 Parts A, B & C

1. UNIT 21:
UNDERSTANDING
VIDEO
TECHNOLOGYU 2 1 A 1 : V I D E O R E C O R D I N G , E D I T I N G A N D
B R O A D C A S T T E C H N O LO G Y

2. GRADING CRITERIA FOR U21A1
REPORT:
P1 - describe the principles of digital video technology and digital video recording with
some appropriate use of subject terminology
• Give definitions of all of the terms covered in this presentation
M1 - explain the principles of digital video technology and digital video recording with
reference to detailed illustrative examples and with generally correct use of subject
terminology
• Find examples (pictures) that are relevant to the definitions
D1 - comprehensively explain the principles of digital video technology and digital video
recording with elucidated examples and consistently using subject terminology correctly
• Use secondary sources of information (quotes/articles/screenshots from films) to
support what you are writing about

3. TELEVISION STANDARDS AND
CONNECTION SYSTEMS
a) The RGB system
- This is the standard colour system used in TV & Film
- The primary additive colours are Red, Green & Blue
- The human eye sees all colours as a combination of these colours
- The secondary additive colours are Yellow, Cyan and Magenta
- Televisions and computers display all colours as a combination of these colours
- Cameras covert these colours

4. TELEVISION STANDARDS AND
CONNECTION SYSTEMS
b) TV Standards
The following are colour encoding systems for analogue television
- PAL – Phase Alternative Line – was used in the UK and parts of Europe
- NTSC – was used in the US
- SECAM – was used in France
The following are colour encoding systems for digital television
- DVB – Digital Video Broadcast – used in the UK and many other companies
- DTMB - Digital Terrestrial Multimedia Broadcast – used in China
- ISDB - Integrated Services Digital Broadcasting - used in Japan

5. TELEVISION STANDARDS AND
CONNECTION SYSTEMS
Two methods used for "painting" an image on a television screen:
• Interlace (for example 1080i)
– PAL – scans 50 lines per second (25 odd, 25 even)
– Needs to be de-interlaced by televisions and computer monitors
– Can create ‘artefacts’.
– Signal bandwidth – cheaper as it requires less bandwidth
• Progressive (for example 720p)
– All lines are drawn in sequence
– Requires more bandwidth

6. TELEVISION STANDARDS AND
CONNECTION SYSTEMS
c) HDTV – High Definition TV
– 1080 lines at 30 frames per second (FPS)
– A lot higher and faster than the analogue TV Signal which was 625 lines at 25 FPS
– This faster refresh rate of the frames means that the resolution is much higher
d) Aspect Ratio – to do with the width and height of the image
– TV and films were traditionally 4:3
– Screens with greater width are widescreen – 16:9
– Examples are on the next slide

8. TELEVISION STANDARDS AND
CONNECTION SYSTEMS
e) Connection Systems:
– Phono Connections have one video line and two audio lines
– SCART connections separate luminescence (brightness) and Chrominance (colour RGB)
– Serial/Parallel Port connections are used in digital systems/computers
• Please research the following and explain where they may be used – also look at USB
& Firewire

9. BROADCAST SYSTEMS
A) Terrestrial Broadcasting
– The transmission of a TV signal without it leaving the earth’s atmosphere

10. BROADCAST SYSTEMS
B) Satellite Broadcasting
– The transmission of a TV signal which leaves the earths atmosphere and is beamed back to
the earth via satellite

11. BROADCAST SYSTEMS
C) Multiplexes
– Technology that enables several signals to be transmitted at the same time along the same
path – e.g. multichannel television

12. PRODUCING IMAGES AND SOUND

13. PRODUCING IMAGES AND SOUND
• How images are produced
– Light passes through the camera lens
– The image is focussed on the prism
– The light is split into its 3 primary colours
– The 3 beams of light pass to 3 Charge Coupled Devices (CCDs) or image sensors
– The CCDs transform the light into electrical signals
– These signals are then converted through a series of microchips into a digital image
– This digital image is then stored (usually on an SD Card)
– The amount of light that reaches the CCDs is determined by the Shutter Speed and Iris
Aperture

14. PRODUCING IMAGES AND SOUND
• The Iris
– Can be opened up or closed down
– Smaller aperture = less light
– Larger aperture = more light

15. PRODUCING IMAGES AND SOUND
• Shutter Speed
– This is the amount of time that light is processed for each frame
• Slow shutter speed = more light
• Fast shutter speed = less light

16. PRODUCING IMAGES AND SOUND
• White Balance
– a control on the camera that
compensates for the colour
effect of day light (blue) and
artificial light (yellow)
– Different light has different
temperatures and will look
different on camera
– White balance compensates
for this change in
temperature/light

17. PRODUCING IMAGES AND SOUND
• Focus
– Focus is adjusted by changing
the position of the lens in
relation to the prism
– This helps to sharpen or blur
the image

18. PRODUCING IMAGES AND SOUND
• Microphones
– How sound is produced
• The head of the microphone vibrates a diaphragm around a magnet when it picks up sound waves
• This produces and electrical signal in the coil