​Keeping track of virtual space

Philip Stevens looks at a recent innovation in the virtual world of television

There’s been a significant increase in the use of virtual sets for a raft of production genres in recent years. And with that growth has come new and innovative ways of improving the look and complexity of such systems – especially when it comes to tracking.

One of the most recent has resulted from a strategic partnership between Vizrt and motion capture technology specialist, Vicon.

“Vicon has been working on this solution with Vizrt for approximately 18 months,” explains Warren Lester, product manager at Oxford based, Vicon Motion Systems Ltd.

He goes on to explain that the Vicon solution broadly consists of multiple tracking cameras that observe reflective markers rigidly mounted on the moving studio cameras. “The Vicon cameras generate data that is streamed to Vicon Tracker, a piece of software that then converts this stream of 2d information into precise 3d position and orientation of the studio cameras. This is then broadcast to Vizrt Tracking Hub in real time over a local area network.”

Additionally, Vicon Studio is a setup wizard that automatically measures the position of the broadcast cameras’ sensor relative to the Vicon markers mounted on the camera.

Gerhard Lang, chief engineering officer at Vizrt, adds, “Our Viz Virtual Studio is made up of two components – the Studio Manager and Tracking Hub. The Studio Manager provides a visual representation of the studio and allows the operator to design the co-cyc, hiding the limits of the green screen. The Tracking Hub is the central collection and redistribution point for tracking data that’s fed from cameras and tracking systems. After receiving the raw data from the systems, it converts it into meaningful information for output by Viz Engine which is used for playout.”

Viz Engine is the real-time render engine for virtual sets and immersive graphics. It takes the tracking data converted by the Tracking Hub and adds camera movement and keys the set before rendering the final composition. This now includes camera movement, presenter and virtual set graphics as an SDI or IP output.

Eliminating complexities

So, with other tracking systems on the market, what makes this special? “The Vicon solution is very scalable and provides tracking capabilities for small to large studios,” reveals Lester. “Everything being tracked within the studio is measured using the same datum, therefore eliminating complexities found when integrating different tracking solutions, or even combining several of the same. The Vicon solution has a high level of precision which makes it perfect for generating jitter free tracking, even when used with long focal length lenses and high resolution video.”

Currently, the Vicon solution works with Canon and Fujinon lenses with built in encoders, but the company is looking at integrating other devices as and when required. “The Vicon system only takes around 30 minutes for a full calibration and then a quick, one-minute daily check takes place to ensure no parameters have changed. This is one of the huge benefits of this partnership – a fast, easy-to-set-up system,” maintains Lester.

Lang says that as far as the Vizrt’s side of the system is concerned there’s no need for calibration. “The Viz Virtual Studio application allows us to build virtual environments in any studio space, and means immersive graphics can be used in any environment – including outdoors. It’s also designed to be part of the journalist’s workflow allowing elements of the virtual studio to be controlled through playlists. These can be defined using templates within a newsroom control system like iNews, ENPS or any other system.”

The workflow

All the virtual set background designs exist within the Vizrt database as meta-data that can be easily called up within seconds. This makes changing sets for a studio a really fast job for the operators.

To edit the design of any backgrounds, designers simply open up their set in Viz Artist, and use the software to make the changes they need. “These alterations can be seen live in the virtual set so the designer can create it with the final output in mind – it makes sure they know exactly what kind of space they’re working with,” says Lang.

Lester adds, “If you were setting the up the workflow for a specific show the process is really simple. All you need to do is select the camera or cameras and props that are to be used in the Vicon Tracker software. With a high resolution of 16 Megapixels, the Vicon Vantage V16 cameras can be used to track in a practically limitless environment. Realistically, 10-16 cameras are required for a typical studio. And there’s no reason why the system cannot be used in an OB environment.”

In either case, the vision mixing can be done with any physical units, but also with software-based switchers such as Viz Opus and Viz Mosart automation systems. In fact, no physical switcher is required because the virtual set feeds replicate a camera source for the switcher.

Adding graphics

Any other graphics, such as lower thirds or tickers, can be easily added downstream on the switcher or automation system in the same way as any live production. “This is one of the key things we wanted to address when designing the system so there’s is no change in this workflow,” declares Lang. “If those graphics have to be changed for, say, a breaking news situation, this is where our template-based workflow comes into play. Virtual sets designed in Viz Artist can be created with certain sections that can be controlled by a playlist coming from the journalist. These would typically be a virtual video wall or immersive object.”

The journalist can easily make the choice for which graphics to present using templates in their newsroom system. Saving them as MOS (Media Object Server) objects in the story adds them automatically to the playlist. In the case of breaking news, it’s just a matter of making a change to the graphics in the newsroom system and the change will appear in the playlist, ready to go on-air. This is the same workflow that would be used for adding a breaking news lower third to the rundown.

One of the first Vizrt/Vicon tracking solution to be installed was completed in May for Hunan TV in China. And with both partners expressing satisfaction with the working arrangement, more will follow shortly. “We’re so pleased with this partnership – pairing Viz Virtual Studio with Vicon in this way gives users an amazing system. Vicon offers an extremely accurate system that is perfectly suited for fixed sets with multiple cameras and future-proof even for 4K productions,” says Lang. Lester agrees, “We are also very pleased to be partnered with Vizrt and look forward to developing the relationship and solution in the future to help the company differentiate itself from other Virtual Reality solutions by providing really unique tracking tools.”

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