How Do LED Video Walls Work?

Understanding how LED video walls work helps you make better decisions about pixel pitch, resolution, refresh rates, and system integration. This guide walks through the technology from the LED pixel up to the content delivery system.

Step 1: The LED Pixel

The fundamental unit of an LED display is the pixel, which consists of three sub-pixels: red (R), green (G), and blue (B) LED chips, often encased together in a single package called an SMD (Surface-Mounted Device) or, in newer designs, a COB (Chip-on-Board) package.

By independently varying the forward current through each R, G, and B chip — typically at 16-bit depth per channel — the display can produce over 281 trillion colour combinations. This is what gives modern LED walls exceptional colour accuracy and smooth gradients.

Step 2: The Cabinet / Module

Pixels are arranged in a regular grid and bonded to a PCB (printed circuit board). Multiple PCBs are assembled into a LED cabinet (also called a module or panel), typically 500×500mm or 500×1000mm. The cabinet also contains:

• Receiving card: Decodes the video data signal and drives the LED driver ICs
• LED driver ICs: Regulate the current to each individual LED sub-pixel with high precision
• Power supply unit: Converts mains AC to the DC voltages required by the drivers and LEDs
• Thermal management: Aluminium housing and, in some designs, fans or heat pipes to manage operating temperature

Step 3: The Video Processor (Sending Card)

The video processor is the brain of the system. It accepts standard video inputs (HDMI, DisplayPort, DVI, or IP stream), scales and maps the content across all cabinets, and transmits the pixel data to each receiving card simultaneously via Ethernet cables or fibre.

High-quality processors from Nova Star, Brompton Technology, or Linsn can handle:

• Multiple simultaneous input sources
• Per-pixel brightness and colour calibration
• Refresh rates up to 3,840Hz (imperceptible flicker in camera shots)
• HDR content (High Dynamic Range)
• Real-time colour profile adjustments

Step 4: Refresh Rate and Greyscale

Refresh rate is how many times per second the entire display is redrawn. A standard display is 60Hz. Professional LED walls operate at 1,920Hz or 3,840Hz — this matters when the display will be captured on camera, as lower refresh rates cause visible horizontal scan lines in footage.

Greyscale depth (bit depth) determines how many brightness levels each sub-pixel can reproduce. 14-bit or 16-bit processing eliminates banding in dark-to-light gradient content.

Step 5: Calibration

Every LED chip has slight manufacturing variations in brightness and colour. Without calibration, tiled panels would have visible brightness inconsistencies across seams. LED walls are calibrated using:

• Factory calibration: Each cabinet is tested at the factory and correction data stored on-board
• Site calibration: A photometer or camera system captures the assembled wall under a uniform test pattern; the processor adjusts per-pixel correction curves to achieve seamless uniformity

Step 6: Content Delivery

Content reaches the LED wall through several paths:

• Media player: A dedicated device playing scheduled content (images, video, data feeds) to the wall automatically
• PC/laptop via HDMI: Direct connection for presentations and live events
• Video switcher: Manages multiple live sources (cameras, feeds, graphics) during events
• IP streaming: Network-based content delivery for distributed display networks

SMD vs COB vs Mini-LED: Panel Technologies