Nowadays, meeting relies on technology more than before. Thus, the video system becomes the core of the conference room that any room designer should consider, taking into accounts a variety of factors such as resolution, size, ratio, video signal, etc. This is in order to perfectly manage both the utility and efficiency. The fundamental aspects of the video signal are listed below.
Resolution
Resolution is the number of pixel dimensions combined into an image, usually quoted in width x height.
Pixel
A pixel is the basic unit for display. It is represented as a dot, and many dots combined into an image. Each image is a result of the different intensity of these pixels (resolution, sharpness). Hence, normally, a display monitor’s physical specification is measured by the resolution of these pixels.
The more pixel packed into an area of width times height, the higher the resolution. Both horizontal and vertical pixel resolution are specified, such as 1024 X 768 means there are 1024 pixels horizontally and 768 pixels vertically – an image consists of 786,000 pixels. Nowadays, the highest resolution in the audiovisual industry is 8K.
Aspect Ratio
The aspect ratio is the ratio of width to height for an image as listed.
Image aspect ratio
- Ratio of 1:1 – the dimension of width and height is 1 X 1 resulted in a square image
- Ratio of 4:3 – the dimension of width and height is 3 X 4 resulted in rectangle image
- Ratio of 16:9 – the dimension of width and height is 9 X 16 seen in cinema or called widescreen
Display aspect ratio
- Square Format (1:1) refers to the display size 70”x70” or 50”x50” as the height and width are equal, thus the image becomes a square
- Video Format (4:3/1.33) refers to the proportional relationship of the height and width of a display as 4:3 like television display. This type of display is normally measured by the diagonal size e.g. 150”. A 4:3 ratio means that the size is 3.05M in width and 2.44M in height with the diagonal size of 150”
- HDTV format (16:9/1.78) refers to the proportional relationship of the height and width of a display as 16:9 as widescreens like cinema screen or the image from DVD player which is a rectangle image with longer width than the 4:3 ratio
The sample of display ratio for HD image
The aspect ratio of the HD image is quoted as width x height of 16×9 (16:9) which is equal to the proportion of the width to the height as 1,920 x 1,080 and 1,280 x 720 which are similar to 16:9.
- VGA (Video Graphics Array) refers to the image size of 640 x 480 pixels (4:3)
- XGA (Extended Graphics Array) refers to the image size of 1024 x 768 pixels (4:3)
- UXGA (Ultra Extended Graphics Array) refers to the image size 1600 x 1200 pixels (4:3)
In addition, there are also other dimensions which their name begins with W for Wide Screen
- WXGA (Wide Extended Graphics Array) refers to the image size of 1280 x 800 pixels (16:10)
- WUXGA refers to the image size of 1920 x 1200 pixels (16:10)
- WXGA (HD-Ready) refers to the image size of 1366 x 768 pixels (16:9)
- WSVGA (Full HD) refers to the image size of 1920 x 1080 pixels (16:9)
Nevertheless, the aspect ratio cannot indicate the sharpness of an image. The resolution will play the part of such information.
Types of video signal
There are various types of connector ports for video signal transmission. Choosing a proper port type is important as each provides different resolution and sharpness.
- Composite Video is a single channel video signal which syncs the black-and-white image data (Y) and image color (C) together as a single channel or composite video, which is an analog signal.
- Separate Video (S-Video): S-Video or Y/C signal is an analog signal which combines Y, U, and V signal together before dividing into two channels. One is chrominance (UV), another is luminance (Y). The benefit of separating into two channels is improving the luminance (Y) transmission and making chrominance (C) decoding easier. It supports 480i and 576i resolution. The signal provides a sharper image than composite video, but still less than those of component video.
- Component: Component Video is another analog signal transmission dividing the signal into three channels. The first channel is a green signal containing luminance (Y) and sync pulse. The second and third channel is known as color difference; the second contains R-Y (red minus Y) or (Pr), while the last blue contains B-Y (blue minus Y) or (Pb). They all support the 1080i resolution image.
- RGB: is a video signal which divides color data into red (R), green (G), and blue (B). Each channel contains chrominance and luminance without the black-and-white image data as Y is combined with all the channels already. However, this scheme wastes some bandwidth as a single signal needs to be sent three times.
- DVI: Digital Visual Interface (DVI) is a digital signal transmission that provides sharper images with less noise. The interface is a mixture between analog and digital types categorized as three groups: DVI-D for digital signal only, DVI-A for analog signal only, and DVI-I for both.
- HDMI is another digital signal transmission system as same as DVI but includes the ability to transmit digital audio as well. The HDMI can support more bandwidth than DVI. For an example, the initial version of HDMI can support 165 MHz bandwidth that is compatible with 1080p and WUXGA (1920 x 1200), for HDMI 1.3, that is upgraded to 165 MHz with an ability to support 2560 x 1600 resolution. Moreover, it also supports a single or dual link as the HDMI single link (Type A/C) supports 340 MHz bandwidth and 680 MHz for HDMI Dual Link (Type B).
Examples of the video signal typesWith the fundamentals of video signal mentioned above, video system design examples should help to elaborate more.
Designing a video system for a conference room can be different according to the functions. The decision on ways of installation, such as installing a desk monitor lift, a projector screen, or a side display instead of the monitor lift to ensure the visibility coverage for the entire seating area, are often revisited several times during the design process. This is to ensure the best design outcome.
