What an LED perimeter board is A line of screens, run as one.
An LED perimeter board is a line of LED cabinets standing along the touchlines and behind the goals, showing sponsor advertising during a match. It is usually around 90 cm of picture, set low enough to sit in the main camera shot, and it can run for hundreds of metres: the boarding round Pittodrie is 246.72 m long.
What the board is made of.
The unit is the cabinet: a frame holding a few LED modules, a power supply and a receiving card. Cabinets are bolted end to end into a run, and the run is fed by cables from an LED processor near the control room.
How sharp the board looks depends on its pixel pitch, the distance between two LEDs: P10 means 10 mm. One stadium can have more than one. Pittodrie mixes three panel sizes to fit thirteen access gates, and Lotto Park runs P6 and P12 across its perimeter and mid-tier ribbon.
From the sponsor’s file to the wall.
The path an advert takes, in order, with the equipment named.
The file arrives
A sponsor or its agency sends a still or a video, in whatever format it was exported in. The playout software converts video to one format it can play smoothly and keeps the original.
It is laid onto the wall
An operator places the artwork on the cabinets it has bought, scaled to the height of the board. The layout is saved and reused match after match.
The rotation is built
Layouts go into a playlist, each for a set number of seconds, and the operator chooses which playlist runs on which screen.
The playout PC renders the wall
The whole wall is prepared as one picture before its turn comes, and the change from one advert to the next happens in a single frame.
A video cable carries it
The playout PC’s graphics output sends the picture to the LED processor at the wall’s frame rate, usually 50 a second in Europe.
The LED processor splits it up
The processor maps each pixel to one LED and sends each part of the picture down its own network cable. A NovaStar MCTRL4K, the processor we meet most often, has 16 of these outputs.
Each cabinet takes its share
The receiving card in every cabinet keeps its own part of the picture and drives that cabinet’s modules. The LEDs light, and the advert is on the pitch.
One wall, one picture.
A perimeter can hold two hundred cabinets and more, but the software treats it as a single screen. That is what lets one banner run across twelve cabinets without a seam, and one key press change the whole wall on the same frame. Because the wall is far wider than any video signal, the software folds it into rows to send it, and the processor unfolds it. How the fold works, and what it means for artwork.
Perimeter, fascia, ribbon.
The same idea appears at different heights in a ground. The perimeter stands at pitch level. A fascia runs along the front of a stand, usually between the tiers, and a ribbon is any long, thin LED strip, sometimes all the way round the bowl. Lotto Park runs a perimeter and a mid-tier ribbon in sync, frame for frame; the Abe Lenstra Stadion has two 44-metre ribbons on its facade.
For the software they are the same problem: a strip much wider than it is tall, artwork that has to fit it, and a rotation that has to change on time. What differs is who sees them. The perimeter is in the television picture; a fascia is mostly for the crowd.
When part of it fails.
A board is built so that no single fault takes it dark. Each chain of cabinets can be fed from both ends, so a cut cable or a dead cabinet leaves the rest of the chain running on the backup line. Modules and cabinets can be swapped while the rest of the wall stays on; UEFA asks for modules that change in under a minute and at least two spare cabinets at the ground.
The playout PC is a single point of failure unless there is a second one. With a backup PC, the backup follows the main one all match and takes the wall by itself after about five seconds of silence. What happens when the playout PC dies. And because every receiving card reports its temperature and voltage, a wall can be watched for faults before anyone in the stand sees one: LED monitoring.
Questions.
- What is an LED perimeter board?
- A line of LED cabinets standing around the edge of a pitch that shows sponsor advertising during a match. The playout software treats the whole line as one very wide screen.
- How tall is an LED perimeter board?
- Usually around 90 cm of picture in football, and about a metre with its frame. UEFA asks for at least 90 cm of display in the Champions League.
- How does the advertising get onto an LED perimeter board?
- The playout PC renders the whole wall as one picture and sends it over a video cable to an LED processor, which splits it into network cables, one per chain of cabinets. The receiving card in each cabinet shows its own part.
- What is the difference between a perimeter board and a ribbon board?
- A perimeter board stands at pitch level, in the television picture. A ribbon is a long, thin LED strip higher up in the ground, often along the front of a stand, seen mostly by the crowd.
- What happens if an LED perimeter board fails during a match?
- A cut cable is covered by a backup line from the other end of the chain, a failed module can be swapped with the wall running, and a backup playout PC takes over if the main one stops. The backup PC in detail.
Planning a wall?
Tell us the ground and the boards, and we will show you how the software would run them.