An LED screen needs a control system to turn a video signal into the data each module displays. It has three parts: a source (a PC, media player or camera), a sending device or video processor, and a receiving card inside each cabinet.
How the signal travels
- The video source sends HDMI, DVI or SDI into the video processor (or sending card).
- The processor scales the picture to the screen's resolution and sends it out over network cables (RJ45, Gigabit Ethernet).
- Each cable runs through a chain of cabinets. In every cabinet a receiving card picks out its part of the picture and drives the modules through flat HUB cables.
Sizing the video processor
Processors are rated by total loading capacity and number of outputs. The Colorlight X7, for example, loads up to 5.2 million pixels across 8 Gigabit outputs, which works out to about 650,000 pixels per output. Add up your screen's pixels, divide by the per-port load and you know how many outputs you need. Also check the maximum width and height the processor supports (8,192 × 4,096 px for the X7).
Sizing the receiving cards
A receiving card can drive a limited number of pixels and has a fixed number of HUB ports for module cables. The Colorlight ACG7512 has 12 HUB75 ports and drives up to 512 × 384 pixels with PWM driver ICs. A 960 × 960 mm cabinet of P2.5 modules is 384 × 384 pixels, so one such card handles it comfortably.
Receiving cards must match the module's driver IC and scan type. That is why module datasheets list the scan (for example 1/32) and why the official configuration file for the module should be loaded with the card.
Players and synchronous vs asynchronous control
- Synchronous: the screen shows whatever the connected PC or source is showing, live. Used for events and stages.
- Asynchronous: a media player stores content and plays it on a schedule, even with no PC connected. Used for advertising screens.
See our control systems or send us your screen size and we will suggest a processor and cards.