LED Wall Mapping Without Stretched or Cropped Content

You send a full-frame image to the wall and get something else back: the logo is stretched, the edges are cut off, or blocks of the picture land on the wrong panels. Almost every one of these problems comes from a mismatch between three things: the physical wall, the layout configured in your control system, and the size of the content you feed it. Get those three to agree and the picture lands where it should.

If you need the basics of how an LED wall is built first, start with our beginner's guide to video walls. This page assumes the wall is already up and the image is wrong.

Why content stretches, crops or scrambles on an LED wall

Each symptom points to a different mismatch:

• Stretched or squashed: the content's shape (its aspect ratio) does not match the shape of the wall in pixels, and something in the chain is forcing it to fit.
• Cropped: the content is larger than the area the wall is configured to show, so the edges fall outside it.
• Scrambled or out of order: the configured layout places panels in a different position or order than they are physically hung, so sections of the image are sent to the wrong cabinets.

Make the configured layout match the physical wall

Work from the wall you actually built, not the drawing you planned:

1. Count cabinets across and down. Write down columns and rows exactly as hung.
2. Note each cabinet's size. Modular walls can be built from different cabinet formats; our Indoor LED Video Wall Panels and Outdoor LED Video Wall Panels are offered in 500 × 500 mm and 1000 × 500 mm cabinet options.
3. Trace the signal path. Follow the data cable from cabinet to cabinet and record the order it actually runs in. If the configuration assumes one order and the cables run another, sections of the picture will appear in the wrong places.
4. Enter that layout in your control system so its grid, positions and cable order match what you recorded.
5. Test with a simple pattern, such as a numbered grid or a single straight diagonal line. A broken diagonal or out-of-sequence number points you straight to the misplaced cabinet.

Count the wall in pixels, not inches

Content should be built for the wall's resolution, and that comes from adding up modules and cabinets. The Canvas LED Video Poster Board is a clear example:

• Each module is 320 × 160 mm and 128 × 64 pixels.
• The unfolded cabinet is 640 × 1920 mm: two modules across and twelve down.
• Two modules × 128 pixels gives 256 pixels wide; twelve × 64 gives 768 pixels tall. The cabinet resolution is 256 × 768.

Apply the same arithmetic to any wall: pixels per cabinet × number of cabinets in each direction. That total is your canvas. Create content at that exact size, or scale it proportionally, and it will not need to be stretched. For The Canvas, content made at the native 256 × 768 portrait resolution displays without letterboxing and avoids scaling artifacts. Rotating horizontal video to fill a tall screen rarely works; purpose-built vertical content does.

Mapping, scaling and switching are three different jobs

• Mapping tells the system where each cabinet sits and which part of the image it should show. Wrong mapping causes scrambling.
• Scaling resizes the incoming signal to the wall's pixel area. Scaling to a different shape causes stretching; scaling to a larger area than the wall causes cropping.
• Switching chooses which source is shown: a laptop, a media player or a live feed. Our indoor panels list HDMI, DVI, SDI, WiFi and USB among their control and input options.

When something looks wrong, check them in that order: mapping first, then scaling, then the source itself.

Splitting very wide content across several processors

When one processor cannot drive the whole wall, the canvas is divided into regions, and each processor is mapped to its own region. The principles above still apply, with two additions:

• Divide on cabinet edges. Each region should be a whole number of cabinets, so every split falls on a physical seam.
• Cut the content to match. Each processor's slice of the image should be the same pixel size as its region, and the slices must line up exactly where they meet, or you will see a step or a gap at the join.

How many processors a wall needs depends on the processor and receiving cards chosen. On our wall systems, the processor, receiving cards and control package are confirmed in the quote before ordering, so the split can be planned around the actual hardware.

Rebuilding the layout for a different event

A modular wall can be rebuilt to a new width and height, but the configuration has to be rebuilt with it. Treat every new shape as a new wall:

1. Record the new cabinet count, positions and cable order.
2. Update the layout in the control system before loading content.
3. Recalculate the total resolution and re-export content to that size instead of letting the system rescale old files.
4. Run the test pattern again.

Displays that change shape need the same treatment. The Trident Tri-Fold LED Poster Display opens into one continuous 1280 × 1920 mm single-sided screen or folds to a 640 × 1920 mm double-sided display. Content made for one configuration will not fit the other, so prepare separate vertical files for each.

Planning a wall that maps cleanly

Most mapping trouble is cheaper to prevent than to fix on show day. When you request a quote for a wall, send the approximate width, height, viewing distance and where it will be installed, and we can help match the panel layout to the space. Video walls are configured as project packages that can include the processor and control hardware along with main and inter-panel power and signal cabling. Browse the full range of video walls or all LED display systems.

Questions and answers

Why is my content stretched on the LED wall?

The shape of your content does not match the shape of the wall in pixels, and the system is resizing it to fit. Work out the wall's total resolution (pixels per cabinet times cabinets across and down) and create content at that size or scale it proportionally.

How do I make the configured layout match the physical wall?

Count the cabinets across and down as actually hung, note each cabinet's size, trace the order the data cable runs, and enter exactly that in your control system. Then check it with a numbered grid or diagonal-line test pattern.

What is the difference between mapping, scaling and switching?

Mapping tells the system where each cabinet is and which part of the image it shows. Scaling resizes the incoming signal to the wall's pixel area. Switching picks which source is displayed.

How do I split very wide content across several processors?

Divide the canvas into regions on cabinet edges, assign one region per processor, and cut the content into slices that match each region's pixel size exactly so the joins line up.

What resolution should content be for The Canvas?

The Canvas has a native resolution of 256 × 768 pixels in portrait orientation. Creating content at that exact size avoids scaling artifacts and letterboxing.