Nothing has changed the face of AV more in the last 10 years than direct view LED. Nearly every customer meeting now includes a conversation about a video wall, and when people say video wall they almost always mean DVLED. As common as it has become, most buyers still arrive asking for the wrong number.
The first number is pixel pitch, the distance between pixels in millimeters. Smaller pitch means more pixels in the same size. A 110-inch 16:9 wall is about 96 inches wide. At 0.63mm pitch that is about 3,840 pixels across, which is 4K. At 1.27mm it is 1,920 pixels across, which is 1080p. For plenty of applications we size the wall from the resolution the content needs, and that arithmetic picks the pitch.
Walls only come in certain pitches, so the size, the pitch, and the resolution all have to agree with what manufacturers make. A customer who needs a 121-inch wall and 1080p content needs a 1.4mm product. If the pitch that fits the room does not land on a standard resolution, the wall still works, but the content has to be built at that custom resolution or scaled to fit, and either way the cost goes up.
The pitch also has to clear the closest viewer. The eye resolves about 1 arcminute, which works out to roughly 11 feet per millimeter of pitch. The working rule rounds that to 10 feet for every 1mm, so a 0.63mm wall is built for someone standing 6 feet from it.
We are working with a new customer now on a 10mm wall. That sounds enormous until you learn that the closest viewer will be in a car about 100 feet away. A finer pitch there would put up pixels nobody can see, and every one of them costs money to drive, to power, and to fill with content.
Size, pitch, and viewing distance are the start. After that come the LED packaging (SMD, COB, and several newer variants), thermal management, local or remote power, cabinet depth, weather rating, and refresh rate if a camera will ever be pointed at it.
The next time you ask for a DVLED wall, bring the closest viewing distance and the content resolution. The pitch comes out of those 2 numbers, and asking for the pitch first is how a wall gets overbought.