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January 15, 2024

7th Sense is “Telling Stories for Fun” in the Sphere

We recently interviewed Paul Breen of The Sphere about the huge and very high resolution (often described as 16k but actually around 19K x 13K in reality) LED display inside the venue. Breen was very complimentary about the company that built the server and control system that runs everything. We followed up to interview Eric Cantrell of 7thSense, the firm involved. He told us that the company specializes in theme parks, spectacles, planetariums and “telling stories for fun”.

There are several key components of the system that work together to allow dynamic control and playout of the pre-rendered and live content. A diagram may be helpful (it helped the writer!).

The key components are:

  • R10 – these are 7thSense’s key playback hardware that run the Actor software which combines the different sources or can also be used with the Conjurer plug-in for generating content
  • The Juggler pixel processors map the content from the R10 stack to the LED panels. They include special output cards developed by SACO to connect to the LED modules.
  • The main pre-rendered content is stored on a huge NAS Server.
  • Controlling all of these components is the Compere software.
  • All the connections between the different parts of the system use fiber to allow huge bandwidth and dismiss any issues of latency caused by distribution

The Compere software is really the key to the system and Cantrell told us that each of the other items of software in the system was based on elements of that application. It has the ability to control and map video and other generated content onto 3D spaces in real time. An extreme example might be to map all the displays in a theme park onto the system allowing complete synchronization and control.

Compere in Control

In Sphere, the Compere system controls the streaming of prerendered video from the NAS system together with the captured and generated content on the R10 stack and makes sure it is mapped to the Juggler systems. The Juggler units effectively know which part of the overall content in the Compere system they are ‘responsible for’ and process it to a format to be sent to the LEDs.

Prior to the development of Compere, all content for this kind of location would need to be pre-rendered at scale, but now live generated and captured content can be included. We asked about the limits of Compere in terms of resolution, but it seems that it was designed to be ‘infinitely scalable’.

The LEDs

The LEDs are also something of a challenge as many of them are not rectangular because of the need to fit into a convex spherical shape. Each of the Juggler systems takes control of a portion of the overall image surface and streams pixel data out to the panels. We also had an interesting discussion about PQ (perceptual quantizer – the transfer function for HDR behind HDR10, HDR10+ & Dolby Vision). He explained that while PQ works well in mapping to the human visual system in controlled ambient conditions, it is less successful where there is a lot of ambient light.

The use of fiber for distribution to the display plane is enabled by output interfaces designed by SACO, the designer and manufacturer of the LEDs. The LEDs, as is usual with LEDs, are composed of separate cabinets, modules and panels. The inter-cabinet interfaces also use fiber.

Not only are the LED tiles not all the same shape, they are also distributed in 3D space, so the Compere software has to be able to understand the 3D architecture to ensure that images are manipulated to look correct when on the display surface. The images and any overlays from content generators or live video are actually processed in the R10 stack using Actor (or Notch) software.

Redundancy is Built-in

All parts of the system are designed to be completely redundant – it can cope with single components failing or with a complete system failure without the audience being aware. The audio system, developed by Holoplot uses beam forming to accurately direct sound. Cantrell told us that this allows multiple different languages to be directed at particular groups of listeners without significant crosstalk.

We were intrigued to see reports that U2 (who opened the venue with a record-breaking series of 17 concerts that earned $110 million in ticket sales) complained that the audio was a bit too clean and needed driving a bit harder to get the distortion that’s a key part of the rock vibe! The band has been lined up to perform another eight shows in December and 11 more from late January to mid-February.

In conclusion, it seems that there really has been no compromise in the ‘back stage’ area to support a new level of resolution and immersion with the reliability needed to satisfy the record level of ticket sales.

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