Video Flashcards
In calculating Luminance, what ratios of Red, Green and Blue light are used, based on the colour sensitivity of the human eye?
Red 30%
Green 59%
Blue 11%
What are the three components of Component Video?
Y Luminance
R-Y Red minus Y
B-Y Blue minus Y
By knowing these three values, the original values of Red, Green and Blue can be calculated and reproduced, even though the Composite signal requires only about a quarter of the bandwidth of the original RGB signal.
What is carried in the five cables of a full bandwidth video signal?
A five cable full bandwidth video signal is also known as RGBHV.
R Red G Green B Blue H Horizontal Sync V Vertical Sync
What is Composite Video also known as?
Baseband Video.
What are the three main physical formats for connecting digital video?
Digital Visual Interface (DVI)
High Definition Multimedia Interface (HDMI)
DisplayPort
DVI has also led to DVI-D, DVI-I and Mini-DVI.
HDMI can also appear as Mini-HDMI and Micro-HDMI.
DisplayPort is also available as a Mini-DisplayPort connection.
What is the difference between the new Apple Thunderbolt 3 connector and the previous Thunderbolt 1 and 2?
Thunderbolt 3 connectors are based on the USB-C interface, whereas Thunderbolt 1 and 2 use the Mini-DisplayPort connection.
How do you calculate signal bandwidth in Hertz for a given video output?
1 Take the total number of pixels in the image (multiply the number of horizontal by vertical pixels).
2 Multiply this by the frame rate (i.e. how many times this image needs to be refreshed).
3 Divide it by 2 to reflect half of the pixels on at any one moment.
4 Multiply by 3 to account for the third harmonic, in order to preserve image quality right to the edge.
Name some examples of Transmissive displays.
The most obvious transmissive setup is a rear projection screen, however backlit LCD displays also come under this banner.
What would be considered a Reflective technology for presenting video?
The main reflective solution is a front projection screen.
Name some types of devices that use Emissive technology for displaying video images.
Plasma, LED and OLED screens are types of emissive technology, as the individual pixels create the light and send it out directly.
Name the three main technologies used to create an image.
Reflective, Transmissive and Emissive.
How do Plasma screens work?
Plasma screens have individual red, green and blue cells for each pixel, and each one lights up as necessary in order to create the required colour.
How does an LCD screen work?
LCD pixels sit in front of a back light (often LEDs) and have individual polarisers to send out light as either red, green or blue. Tiny transistor circuits in front of each polariser switch on and off individually, either passing or blocking the coloured light as required.
What is a display’s Aspect Ratio?
The aspect ratio of a video display explains the relationship between the width and height of the image. Many widescreen displays today are 16:9, meaning that if the height of the screen was divided by 9, the screen width would be 16 times that figure.
Older computer screens used to be 4:3, and although these are rarely seen new these days, many may still be in use.
The width can also be expressed as a ratio compared to the height of the screen, for example 1.33:1 instead of 4:3.
For a more direct comparison of the new screens, (if you multiply both numbers equally by 3) 4:3 equals 12:9, meaning that today’s 16:9 monitors are a third wider than their 4:3 ancestors.
