Live and direct - presentation switchers in a live environment

What are the demands a large scale live event puts on presentation switchers? And how much flexibility can they provide for users? Steve Montgomery finds out.

Video has become an integral part of most high profile events, from corporate shows and product launches to multimedia theatrical extravangazas at the opening ceremonies of global sporting events.  This boom places enormous demands on the rental and staging companies and media production companies that provide equipment and services as well as on the developers of the equipment that delivers outstanding visual solutions and effects.

The size and complexity of some of the installations can be truly staggering.  In every performance at the Han Show theatre in China, for instance, giant robotic arms manoeuvre 4 ton LED screens around and above the stage whilst 16 Christie projectors physically move around in concert on custom yokes.  Audience seating moves to surround a performance pool and new surfaces and screens appear: all requiring visual effects and lighting.  For the shows, visual content is supplied in uncompressed form from VYV Photon media servers, developed specifically for live entertainment and immersive experiences.  Emric Epstein, co-founder of VYV explains that it is not just straightforward delivery of high quality content that is the issue: “The projectors actually realign themselves with the stage set every 60th of a second to synchronise with the movement of props and actors onstage and to enable real-time alignment and edge-blending, even on uneven and angled surfaces.  Even though the moving yokes are inherently very accurate, a slight drift causes a noticeable drift over a throw of 30 metres which we can totally eliminate with this realignment technique.”   

The quantity of visual devices is also expanding enormously: the stage for this year’s Eurovision Song Contest included an array of Barco HDQ-2K40 projectors and over 900 square metres of LED panels containing around 70 million pixels.  Individual media designs were created and shown for the 42 contestants, all driven by 19 Green Hippo media servers. For the event, video content designer Mikki Kunttu worked over the preceding four weeks to develop the content and synchronise it with the performers: “The surfaces are angled and challenging, not like normal flat LED back walls.  There are only a few rehearsals with the performers to get everything right, and we need to make tweaks very quickly, up until the last minute.  The full show was around 9TB of custom made media with over 7,000 clips.”

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This type of presentation places enormous demands, not just on the creative teams, but on media storage, playout and switching equipment.  It requires real time playback and control of extremely high bandwidth and high resolution images in adverse and hostile environments and enormous flexibility to cope with the range of applications and equipment used in a single event.  

“Equipment used at the higher end of large event presentation needs to be rugged, powerful and flexible,” says David Griffiths, director, market development, systems solutions for Christie.  “The majority are temporary installations and operators need to be able to quickly reconfigure and deploy image processors each time.  Servers and switchers need to have a range of input and output connections, with low latency, high bandwidth and flexible pixel spaces.  Also, having a standard processor that can be cross rented and connected together for larger shows is a boon.  The ability to control downstream switchers and players is extremely important; being able to demand the correct input and also to play the correct media at the right time are normal functions for high end presentation equipment.”  

Real time image manipulation is fundamental to live events, but requires high-power processing.  “Image processors, must be able to quickly manipulate imagery and format the output for display,” he points out. “That may include windowing, resizing, format conversion and even stereoscopic display; all in real time and at the highest level of quality possible.”

The Hippotizer media servers used at the Eurovision Song Contest were powerful devices capable of storing massive amounts of content and replaying it at real time.  The servers have the ability to perform extensive video manipulation and visual effects, including 3D mapping and contouring and deliver content to individual outputs for show control and switching.  They also have the capability of being networked together into larger arrays and synchronised control of other devices, like lighting rigs.

Paul Wigfield, director, QED believes that the best solution through a combination of dedicated devices: “On high profile events switchers and media servers should always be separate devices and concentrate on what they do best - servers should play media and switchers should be able to transition seamlessly between multiple sources. It's easy to get distracted or confused by the variety of features that manufacturers try to build into media servers and switcher-scalers as they can all perform similar functions at different levels of quality and capability.

Because it often gets down to the nuances of the show requirements, it's good to have as many options as possible.  Features such as keying, titling, picture-in-picture can be applied at source in the media server or in the mixer, so it's really a question of choosing the most appropriate tool to do the job and to make live operation easy as possible.  If you were to truly combine a media server and a hardware switcher then you are likely to end up restricting its capability to adapt to technological developments.”

Philippe Vitali, marketing and communications director at Analog Way agrees: “Media servers and switchers must be considered separately, especially because every device has its own function and owns different properties.  Switchers play a key role: they are the backbone of the set up, and they must be extremely reliable.  Most media servers are based on a PC platform.  They are not adapted to support mission-critical environments and they do not provide the same level of reliability.  An all-in-one media server-switcher would therefore not provide the expected level of dependability.   Nor does it allow optimisation of the stock management and usually does not meet the client’s needs.  

“However, making them cooperate is desirable, because media servers are generally used as sources. The Vertige premium show controller designed for large and multi-display shows allows the user to operate switchers and media servers simultaneously.”

The requirement for ultimate reliability influences the design of the devices.  Different architectures enable different capabilities and applications according to processing and bandwidth capability. PC based image processors rely upon transferring data over PCI buses and this becomes the pinch point in terms of bandwidth.  An increase in the number of windows, greater resolution and increased pixel manipulation adversely affects the image refresh rate and quality on the screen. Dedicated hardware-based image processors generally do not have data buses and are capable of creating final images with very low latency no matter how many windows are being displayed.

Customer requirements differ widely across the sector, as each event will have specific characteristics and incorporate a variety of techniques and technologies.  Presentation switchers and the ancillary equipment have to accommodate all eventualities says Wigfield: “There is very little difference between the media servers and switchers we use for live entertainment and corporate productions.  The main difference is usually the increased number of inputs and outputs required of the switching system.  We tend to use the same equipment across all types of event; the only thing that varies is the particular combination of hardware.  On projection mapping projects it's very much all about the media server, so all that's usually required from a switcher is unprocessed signal distribution and clean switching with network control.”

The constant demand from users for ever more sophisticated technological capability and image handling is being felt by the manufacturing industry. Eric Plante, general manager, VYV, lists some of the requirements: “Users constantly seek better performance and functionality.  Resolution up to 4K @ 60Hz is needed but there are currently very few offerings on the market.  There does not seem to be an established and widespread means to transport 4K60p at the moment. 12G SDI was published by SMPTE in March 2015, but very few devices support it and we've observed that confidence in 12G infrastructure is low in our markets. DisplayPort seems more solid, but forces the use of fibre for all but the shortest distances, which drives up costs quite significantly and again, options are very limited.

“On the switcher side, switching has to be clean, seamless and with the absolute minimum delay, ideally through a simple TCP protocol, for control and query.  Also the size of an event installation varies considerably.  We work on projects from very few to 75, or more, independent signals.  So a modular solution is desirable for larger projects, allowing additional I/O cards to be added to a frame as needed.

Tools to aid in the design, installation and operation of complex multi-channel display installations to ease the integrator or operator’s workload are becoming available.  One such is Christie’s Mystique suite.  Gary Klosson, director of solutions outlines the system: “It models the effect created by multi-projector installations; the brightness levels and image overlaps, dot pitch and how projected live content will appear.  It can be visualised on a VR headset or a 3D model can be produced and linked to pico projectors for a more realistic simulation, allowing edge blending and alignment to be set prior to the real event.  It also includes remote recalibration and alignment monitoring of the live system.”

As shows become more sophisticated there is an increasing demand for more creativity and integration and cooperation between the strands of technology used.  Major events are regularly broadcast to live audiences and this adds additional complexity and demand onto the creative teams.  “The role of the creative producer is to paint pixels onto sets, rather than just combine disparate elements onto individual screens,” says Andy Hook technical solutions director at White Light.  “Stages nowadays rarely have rectangular or even flat screens.  Instead visual displays are built into and wrapped around the shapes on the set.  Projection is regularly used, with mapping around intricate designs. Lighting is becoming ‘pixelated’ as the units themselves are combined into the video material and become an extension of it.  
“Visual technology operators strive to produce a complete and immersive effect.  Fortunately we have new devices like those from d3, who provide platforms that combine media serving and switching together and allows us to manage multiple HD and 4K video inputs with stored content, add lighting and control the whole event as a massive, single canvas from a single point.  It’s much more about the whole media workflow than control of individual elements and that enables us to create much more cohesive and integrated visual effects.”

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