The LED display screens on the market are generally divided into five types, mainly including the following technical parameters: pixel runaway rate, grayscale, control method, non-linear grayscale conversion and driving method. Simply speaking, the out-of-control rate of pixels is the proportion of abnormal working conditions. Grayscale is the brightness of the LED media screen. It is divided into three levels, namely 16, 32 and 64 levels. The control methods can be divided into two categories: the networked version and stand-alone version. Among them, the gray-scale nonlinear transformation is to transform the gray-scale data according to the empirical data to the display screen in a nonlinear function relationship. At present, there are two main driving methods: constant voltage driving and constant current driving.