U21 A1 delivery powerpoint
- 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