How To Determine The Resolution Of A Video Wall?

The reason for setting up a video wall varies, mainly depending on the individual or organisation. The usage decides the specifications, as a video wall used for digital signage in public will have entirely different requirements and needs than a video wall in a command centre. When putting up a massive video wall, you will need to consider various parameters, such as resolution, pixel pitch, aspect ratio, and size, as well as the types of input sources and the number of sources that will be displayed at once.

The “resolution” of a video wall is calculated by adding the total height and width in pixels. A wall can exhibit more detail and appear more impressively with higher resolution.

“Resolution” is a widely used term for picture clarity. Display resolution is typically expressed as width x height in pixels. Among the display resolutions frequently mentioned in the professional AV sector are:

Full HD (high definition) is 1920 x 1080, or 1080p.

Ultra HD is 3840 by 2160.

4K = 4096 x 2160

8K = 7680 x 4320

Features such as clear, detailed images and a lack of visible pixels can be used to judge the resolution of a video wall. The primary purpose of a higher resolution video wall is that when you zoom into a presentation, the clarity of the image will remain intact and will not pixelate.

But what exactly is resolution?

Let’s start with the fundamentals: pixels make up the image projected on a video wall. Instead of totalling up all the pixels, resolution can also be expressed as the number of pixels per area unit. Since the number of pixels determines the resolution in a specific area, such as a screen or video wall, displays of various sizes can have the same resolution. 

Resolution is a vital factor to consider when displaying huge or intricate graphics on a video wall. Each operator in a command and control environment should be able to clearly see the specifics of the data displayed on the operation centre video wall. A higher resolution is necessary if the video wall is displaying content from several high-quality sources.

How do you choose the correct resolution for your video wall?

Single and multiple display video walls with higher resolution are expensive. So determining the required resolution for a video wall according to its usage is vital. A few factors determine the correct resolution for your video wall, namely:

Approximate viewing distance

• Visual Acuity Range
  The Visual Acuity Distance, often known as “Retina Distance,” is a formula that determines how far a person with 20/20 vision must go in order to lose the ability to differentiate individual pixels on an LED video wall. The formula is pixel pitch(in mm) * 3438 scale factor in 1 arc minute = Visual Acuity Distance.
  
• The average viewing distance 
  The average comfortable viewing distance is the distance at which most individuals are expected to find the look of the video wall tolerable. This estimate is based on numerous installations made in the current world. The average comfortable viewing distance is arbitrary and affected by a variety of factors, including the viewer’s vision, the application, the content resolution, and the type of content (e.g. video vs spreadsheet). 

• 10x Rule
  An easy way to determine an approximation of the visual acuity distance is to use the 10x Rule. The formula for the 10x Rule: Pixel pitch in mm * 10x multiplier = Approximate Viewing Distance in Feet

Once you have determined the convenient viewing distance for your video wall, you can move on to the other calculations.

Pixel Pitch

Pixel pitch determines the resolution of a video wall. Video walls with small pixel pitch have a higher density of pixels, which is used to form the image. Therefore resolution increases as pixel pitch measurement decreases. Pixel pitch is easy to determine once you have nailed down the purpose and viewing distance for the video wall. There are five crucial factors to consider when choosing the right pixel pitch for an LED video wall.

• Size of the board:
  The appropriate pixel pitch can be calculated by working backwards from the target size of your LED board. For a rectangular board with a longer horizontal length than the vertical dimension, as a general rule of thumb, divide your horizontal dimension by (1.9m) 6.3 feet to get your pixel pitch to obtain a standard resolution of 1920 x 1080. (in mm). Due to the fact that 25.2 / 6.3 = 4, a 4mm pixel pitch is ideal for, say, a 25.2 (7.6m) by 14.2 foot (4.3m) board.
• The ideal viewing distance:
  If you know the proper viewing distance for your LED board, such as the distance to a billboard from a highway, you can divide your intended viewing distance (in feet) by 8 to determine the correct pixel pitch (in mm). Since 32 / 8 = 4, the pixel pitch in this instance would be suitable for a viewing distance of 32 feet (9.7 metres).
• Indoor versus outdoor:
  Since outdoor screens are often viewed from a greater average viewing distance, they can use a bigger pixel pitch, i.e., lower resolution, without sacrificing the consumer experience. However, indoor screens are often viewable at a distance of across a room or lounge, making a smaller pixel pitch, i.e., higher resolution, more critical in this scenario.

How to Calculate Resolution Using Pixel Pitch?

As previously stated, the smaller the pixel pitch, the higher the resolution. This varies in a video wall when you combine multiple displays together. 

Here is a quick algorithm to determine one LED display’s resolution in a video wall.

For example, let us assume the dimensions of one display screen are 500 x 500 (w x h), with a 2 mm pixel pitch. So, this is how you determine the display’s resolution.

Since we always write pixels in width x height. The pixel resolution in this scenario for one display is 250 x 250.

Suppose the LED video wall has 4 cabinets wide-wise and 2 cabinets height-wise. Then the whole screen resolution is then determined as shown below.

Screen Resolution (Width) = one display width resolution x No. of displays in width

= 250 x 4

Video Wall Resolution (Width) = 1000 px

Video wall Resolution Height = one display’s height resolution x number of displays in height

= 250 x 2

Video wall Resolution(Height) = 500 px

Hence, the entire video wall resolution is 1000 x 500 px (w x h).

Conclusion:

The formula to find the resolution of one display in pixels is height or width divided by pixel pitch. The formula for the entire video wall is to multiple the resolution of one display into the number of displays arranged height-wise and width-wise, respectively. The resolution can be calculated only after you finalise the purpose of your video wall, the comfortable viewing distance, and the required visual acuity.