AR Graphics at the Eurovision Song Contest 2025
StarTracker Max camera tracking as a service for arena-scale live broadcast events
Project Overview
On 17 May 2025, the Eurovision Song Contest (ESC) Final went live from St. Jakobshalle in Basel to 166 million viewers across 37 markets. The host broadcaster wanted augmented reality woven into the show – virtual graphics placed within the set, holding firm as cameras swept across the arena.
Mo-Sys was approached by NEP to provide the rock-solid camera tracking that would be used to lock those AR graphics in 3D space.
Rather than supply hardware alone, Mo-Sys sent Martin Parsley, Lead Developer for Optical Tracking, and a team of Mo-Sys technicians to Basel to install, calibrate and run StarTracker Max on site, overseeing tracking throughout the live event.
Project Partners
European Broadcasting Union (EBU) – Format owner, rules setter and overall organiser of the competition.
SRG SSR – Host broadcaster and producer of the 2025 contest.
NEP Group – Official media services and broadcast infrastructure provider.
Mo-Sys Solutions – On-site camera tracking service for AR graphics, delivered with StarTracker Max.
The Production
The 2025 contest was delivered by a production team of around 700 people, with roughly 250 working directly on the live show and TV broadcast – from stage crew managing props to camera operators, follow-spot operators and multicamera directors.
The show was captured in HD across 25 cameras, eight of them wireless, with two cranes, several dollies and a CableCam system. Two NEP OB trucks served as the control rooms.
- Cameras: 25x Sony HDC-3500/4300, P50, PXW-Z450, FR7 (eight wireless)
- Automated camera scripting: LiveEdit
- Graphics: CasparCG
- Camera tracking: Mo-Sys StarTracker Max, operated on site by Mo-Sys
Mo-Sys mounted StarTracker Max systems to the two AR camera setups, a CableCam and a dolly system, that would stream exact position, orientation and lens data to the graphics engine in real-time.
The Venue
St. Jakobshalle is Basel’s multi-purpose arena that seats 8,000 or hosts a standing audience of up to 12,400.
With such a large set and broadcast infrastructure, the ESC Final would have an audience of approximately 6,500 people inside the hall.
Florian Wieder’s mountain-inspired stage pushed a catwalk deep into the standing crowd, framed by a self-supporting LED arch. Above it ran the biggest lighting rig in Eurovision history: around 4,500 fixtures and 24 automated overstage trusses that reshaped the space for every act.
Venue details and insights
- Capacity: 8,000 seated / 12,400 with standing audience
- Ceiling height: 17.65 m
- Video: 750 m² transparent LED wall, LED floor, 16 projectors
- Lighting: c. 4,500 fixtures; 24 automated overstage trusses
Mo-Sys Insight
“Eurovision is one of the biggest live broadcasting events in the world, and there are no second takes. Putting our own engineers in the venue meant the production had that extra layer of confidence, knowing that the leading experts, the people who build StarTracker technology, were on site to ensure perfect tracking throughout the event.”
Selin Kemal – Managing Director, Mo-Sys
The Challenge
The Final was a single live broadcast: 26 acts, each with its own staging, lighting and camera plan. For the AR graphics to work, the tracking had to be perfect on every pass, and the venue made that harder in three ways.
A busy, moving roof - Thousands of fixtures and 24 automated trusses shared the overhead space with the star field, reconfiguring between every song.
Movement - One of the tracked cameras was mounted on a CableCam system, flying across the arena. The graphics had to stay locked through every fast, sweeping move.
Height - St. Jakobshalle’s ceiling sits 17.65 m above the floor – exceeding the studio grids that standard StarTracker stars are sized for.
Mo-Sys Insight
“Normally, StarTracker customers operate the system themselves – it is designed for exactly that. But for a one-off event in a new venue, the production wanted the experts in the room. Mo-Sys delivered camera tracking as a service: Martin Parsley and the Mo-Sys team took ownership of star design and layout, calibration and live operation, on site throughout the broadcast.”
James Uren – CTO, Mo-Sys
Camera Tracking at Scale
With a traditional studio installation, StarTracker Max reads a pattern of small retro-reflective stickers on the ceiling above the camera. From that pattern it calculates the camera’s absolute position and orientation, with no drift and no daily recalibration, combining it with zoom and focus data so the render engine’s virtual camera matches the real one exactly.
Because StarTracker tracks inside-out, with the sensor on the camera looking up at fixed references, the CableCam could fly anywhere across the arena without line-of-sight to an external camera array. The same principles that make StarTracker reliable in a studio carried straight into an arena with a capacity of 12,400.
However, at more than 17 metres, a standard star would have been slightly too small for the sensor to reliably detect. For the Basel venue, the Mo-Sys team mapped the arena roof with custom, larger stars, positioned to stay visible around the automated trusses and lighting.
Mo-Sys Insight
“The principle is the same in a studio or an arena: the sensor reads the stars and works out exactly where the camera is. At nearly 18 metres, we made the stars slightly bigger and placed them deliberately, so the sensor always had a clean pattern to read above a roof full of moving trusses.”
Martin Parsley – Lead Developer, Optical Tracking
The Outcome
For the production, the result was AR with no added risk: the tracking was designed, installed and run by the engineers who designed it, on one of the largest live broadcasts in the world.
The AR graphics held their position perfectly throughout the live broadcast of the Eurovision Song Contest Final. On both the CableCam and dolly shots, virtual elements stayed locked to the set as the cameras moved, with no drift and nothing to distract from the viewing experience.
