Brompton

Overview

Brompton typically refers to Brompton Technology on set, a London (Chiswick) based manufacturer of LED video processors. Brompton does not build LED walls or lights themselves, but rather the processing system that receives an image signal and prepares, calibrates, and distributes it correctly to the individual LED modules of a wall. The product line is called Tessera and consists of the processors (sending units) and the associated Receiver Cards, which are located in the LED panels.

In film and TV, Brompton is primarily known as the de facto standard for Virtual Production and In-Camera VFX (ICVFX), meaning for shooting in front of large LED volumes (LED Volume / LED Wall), where the background is generated live in-camera rather than through green screen compositing. Whether an LED volume can be displayed accurately and color-neutrally for the camera is primarily determined by the processor used.

Tessera Product Line

Brompton markets several processors with tiered performance, as well as receiver cards:

According to the manufacturer, the Tessera SX40 is designed for 4K walls at 60 Hz with 12-bit color depth per channel and is housed in a 2U rack format. It features, among other things, HDMI 2.0 and 12G-SDI inputs, as well as 10 Gigabit Ethernet outputs to the panels. Specific connection and capacity values should always be checked against the current Brompton datasheet for the respective production.

Relevant Functions for ICVFX

Several Brompton functions solve typical problems when filming LED walls:

• ShutterSync: Synchronizes the LED image buildup (scan/refresh) with the camera shutter, thus avoiding scan lines or stripes in the image across different shutter speeds and frame rates. According to the manufacturer, exclusive to SX40 and S8.
• Frame Remapping: Allows multiple camera perspectives with different genlock offsets to be served on *one* wall, so that each camera sees its perspective-correct background.
• HDR and Dynamic Calibration: For high dynamic range and uniform brightness/color across the entire wall.
• OSCA (On-Screen Color Adjustment), ChromaTune, and Dark Magic: Correction of seam and brightness differences, fine-tuning of color, and improved detail in dark image areas.

On-Set Usage

The Brompton processor is typically located in the machine room or rack of the LED volume and is operated by an LED technician or the virtual production crew (often in coordination with the DIT and VFX). For the camera and lighting departments, it is relevant that the processor is used to set the frame rate, genlock, and ShutterSync settings; incorrectly set shutter speeds or missing synchronization will lead to visible stripes or flicker. Since the LED volume also serves as an interactive light source, the color calibration of the processor also influences the lighting of the actors and foreground elements.