LED Video Walls are all the rage in the AV Industry. However, they aren’t walls that you can plug a cable into and play your content. You need an image processor and receiver card to drive content to the wall.

THE NITTY GRITTY

Today, we’re going to talk about processors, and more importantly, why you would need a processor. These are the processors that sit in front of LED walls or in front of large video walls. In order to understand why you need one, you will have to understand the LED walls themselves. What makes a large LED video wall work and what is actually in it? We’re using Unilumin as a frame of reference. Unilumin is our preferred partner for LED. They make the best. They make the most. And they’re readily available.

LET’S TALK PIXELS

All video images are made up of pixels, right? Pixels are produced from a vertical resolution and a horizontal resolution. That’s the number of pixels high by the number of pixels wide.

    • 4K is 4096 x 2160*
    • HS is 1920 x 1080
    • 720p is 1280 x 720
    • SD is 720 x 480

*We understand 4K has many different variants. For this purpose, we are talking about the general concept.

LED DISPLAYS ARE MADE OF PIXELS TOO?

Now that we know that every image is pixels, LED displays are exactly the same. They’re made up of pixels as well. Those pixels vary based on the panel being used.

When you hear people talk about narrow pixel pitch, or direct view LED, they’re talking about the millimeters. That’s the space from one pixel to the next — the size of the space in between those two pixels in millimeters. So, in a .9mm, we’ve got 9 millimeters of space between each pixel. That space is going to determine how many pixels can actually go on the panel that you’re using. The number of pixels goes down when the space between them goes up.

Pixels Per Panel

    • .9mm is 640 x 360
    • 1.2mm is 480 x 270
    • 1.5mm is 384 x 216
    • S2.5mm is 240 x 240

You choose the pixel based on the distance you’re going to be viewing. The general rule of thumb is 10-12 feet per millimeter. So, a .9mm optimal viewing distance is around 10-12 feet and it increases as you go up. For a wide pixel pitch, like a 2.5mm, you might want to be very far away and it will look really good at that distance.

STACKING THEM UP

In order to get 1920 x 1080 HD video, you have to stack multiple panels together to create that large image.

To achieve a 1920 x 1080 image, you need these stacks:

    • .9mm is 3 x 3
    • 1.2mm is 4 x 4
    • 1.5mm is 5 x 5
    • S2.5mm is 8 x 8

All the variants above are the same resolution of 1920w x 1080h, but because of the space between pixels and the viewing angles, they going to change in size accordingly.

4K GETS EVEN BIGGER

To achieve a 4K image of 3869 x 2160, you need these stacks:

    • .9mm is 6 x 6
    • 1.2mm is 8 x 8
    • 1.5mm is 10 x 10
    • S2.5mm is 16 x 16

PIXELS PERFECTED

All this is to say that each of those individual panels carries a number of pixels, and we mount all those together to generate one large image that meets a certain pixel resolution that we are searching for — be it 4K or 1080p or larger or somewhere in between. We can generate any resolution necessary by stacking the correct number of panels together.

If we’re going back to 1080p for a second, 2 million pixels is your total number of pixels in a 1080 wall — 2, 073,600 to be exact. Pixels by themselves on an LED wall are fairly useless. You need something to make them work.

IMAGE PROCESSOR COMES INTO PLAY

The image processor is going to be the gateway to the data, and the receiver card is going to mount in the panel and that is going to be the translator tool that’s going to map those pixels up to the wall.

Your image processor translates the image, so we take video into the image processor and it shares that data to all the receiver cards that are mounted in the LED wall. You get one receiver card per LED panel, and the image processor tells each of those receiver cards what pixels they’re responsible for and transmits those pixels to that receiver card. The receiver cards then translate that data over to the LED panel.

REAL WORLD APPLICATION

With LED walls, we have to go through the image processor. The steps below are applied when using a BluRay player as the video source.

  1. Plug video source into the image processor
  2. Image processor splits that source to each receiver card mounted in the panels
  3. Receiver card spreads the pixels out in the LED wall

Every image processor is responsible for a set number of pixels. A really large 4K wall might require two image processor. An 8K, 16K, or even larger, may require you to expand even more image processors. It’s all going to come down to the version of image processor you choose.

MULTIPLE IMAGE PROCESSORS

One processor may not have enough processing power to manage all the pixels in a wall, or the wall is too big for any one given processor. In that case, we split it up and get more than one processor to break the wall up into two images. Basically, we’re controlling two independent walls but they’re all getting the same image and sharing that image across.

In order to make that work, the source has to be split in order to feed both processors. You need a box that’s going to sit in front of the processors, take the original source content and split it evenly. This is where we get an image scaler to manage the sources going into that wall.

AN EVEN SPLIT?

In this case, we did an even slice right down the middle — Left image / Right image. In some instances, it’s not always like that. It could be 2/3 and 1/3 or it’s just a row of LED panels. It’s not always an even line when you’re looking at your image processor or your video wall. It’s all going to be based on the processor that was chosen and the number of pixels you’re driving in the wall.

X1PRO E FROM RGBLINK

X1pro e Data Sheet

That’s where the X1 Pro-E comes in. Every video wall needs a box like this. It solves problems. Sometimes your incoming resolution doesn’t match your display wall. Sometimes you don’t know what your incoming resolution is going to be or it might need to change. You always want to know the correct pixels will end up on the screen in the correct place.

What is it?

    • 4 DVI inputs
    • 4 DVI outputs
    • Windowing
    • Splicing
    • Scaling
    • Capable of 4K outputs

KEY FEATURES

    • 8Kx1K, 4Kx2K and more
    • Pixel-to-pixel scaling
    • Independent scaling
    • Multiple operation modes including 2K and Dual 2K preview
    • Seamless switching
    • Redundant outputs and hot back up facility
    • TCompact 1U housingy

LEARN MORE ‣ RGBlink
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About RGBlink

RGBlink is Asia’s leading professional video manufacturer. They’re dedicated to developing and building quality video products for professional av applications that make advanced video accessible to a broad range of visual markets.

Founded in 2009 on what seemed to be a simple need – RGBlink has grown rapidly to become the leading manufacturer in Asia of specialized video processing equipment, providing a range of hardware based solutions that continues to revolutionize and democratize video for displays everywhere and anywhere, releasing displays from conventions of format and presentation. | rgblink.com

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