What that wall
actually gives you

Where the numbers come from

• Size is pixels × pitch. A 2.6 mm wall of 22×12 panels of 128 is 2816×1536 pixels and 7.32×3.99 m. No rule of thumb involved.
• The distance where pixels disappear uses one arcminute, the usual figure for what an average eye resolves: a pixel stops being separately visible at roughly 3.44 × pitch metres. That is the strict version of the old trade rule that pitch in millimetres equals viewing distance in metres — which is about three times more generous than the eye actually is.
• Pixels per degree is how much detail lands on the eye at a given distance. Roughly 60 is the limit of useful resolution; below about 20 the structure of the image starts doing the talking instead of the content.
• Readable text assumes a cap height of 16 arcminutes, which is comfortable rather than heroic — the threshold for legibility is around 5, and designing to the threshold is how you get a room full of people squinting.

If a camera is going to see it

Pitch, distance and angle decide whether the wall moirés on camera, and none of those are content problems. Shooting an LED wall covers what actually fixes it, what the wall does to your exposure, and the order to check things in when the camera goes live in an hour.

The one that surprises people

A wall is usually a strange resolution, and almost never 1920×1080. The example above is 2816×1536: wider than 16:9 and not a multiple of anything convenient. Send it a 1080p file and a processor scales it, which is exactly what ruins fine text and one-pixel lines. Building content at the wall's own size is free; discovering the problem on site is not.

Deckboy is free and open source, and it plays at the raster you give it — it also generates test patterns at your exact pixel map, including a numbered panel map that finds a swapped or rotated tile.