Real vs Virtual Pixel Pitch
Real Pixel Pitch
The term if quite simply explained as the measurement between the groups of LED's which make up one pixel.
These are typically in groups of 1 x Red, 1 x Green & 1 x Blue LED i.e. RGB
Sometimes there maybe four LED's to form one pixel, with the addition of an extra Red LED, this is less common though these days.
Virtual Pixel Pitch
Here's where it starts to get a it more complicated, with virtual pixel pitch through the aid of some clever technology, one pixel is able to be share individual LED's with its neighbouring pixel, with the effect that it doubles the screens effective pixel resolution.
Typically you will find a Virtual LED screen will have 4 x LED's per pixel, comprising of 2 x Red, 1 x Green & 1 x Blue LED's.
There are some trade offs with this technology as with everything. So a P10 Real Pixel Screen will have a much sharper image quality than a P10 Virtual Pixel LED Screen for example.