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Multi-player, multi-OS synchronization

If current digital signage trends are an indication, we are about to see a lot more screens in businesses and public spaces. This bodes well for marketers and brand owners who will benefit from the additional advertising space. However, having more screens in larger spaces creates some interesting opportunities and challenges for signage network operators.

When you install many screens in the same area, you need to keep in mind how content will be viewed. If you plan to show the same content on every screen, let’s say a video advertising a product or service, you will probably want all the videos to play synchronized content across all visible screens. Otherwise the content will be slightly off on each screen and the results may not meet your expectations.

This is where multi-player synchronization comes into play.

Typically, individual media players operate on their own. They communicate with a back-end server for new content updates and scheduling information at regular intervals. They also communicate with data feed servers to display news, weather forecasts and other live data.

When you place two media players next to each other and publish the same content on both devices at the same time, there will often be a short delay between the moment each player starts receiving its updates and the time they start to show content on screen. When this happens, content is not synchronized.

The next issue has to do with the internal clock embedded inside each processor. It’s practically impossible to have perfectly synchronized internal clocks. The gap may be in the milliseconds, but it’s always there, so each player’s clock is slightly offset.

When you add these factors, you quickly realize content can’t play in-sync and the longer the content plays, the greater the gap will become.

So how do you synchronize playback across multiple devices?

You use a technology called WebSockets. Wikipedia describes WebSocket as “a computer communications protocol, providing full-duplex communication channels over a single TCP connection”. This simply means WebSockets lets computers communicate with each other in real-time.

In a digital signage context, media player software that uses WebSockets can exchange information between devices to ensure the content is synchronized on every screen. WebSockets also provides a persistent connection so content synchronization can be maintained pretty well indefinitely.

You may think this is well and fine, but what happens when you deploy content to a mix of hardware types running on different operating systems? Like when you have a mix of Windows PCs, Android devices, and System on Chip displays on the same digital signage network.

Well this is where things get complicated. While some digital signage software apps support player synchronization, none support the feature in mixed hardware environments. This means you can possibly synchronize all your Windows players together, but not with Android or SoC players.

Fortunately, Navori made a breakthrough and created a new QL Player software add-on module that supports multi-hardware and multi-OS synchronization.

How does it work?

Navori’s engineers created a time stamp streamer that synchronizes each media player’s clock with QL Server. This feature is precise to 1/20th of a second so content is fully synchronized across all devices. There’s only one requirement. All synchronized content must have the same duration.

Navori customers can publish videos, images and templates with embedded objects and live data knowing the content will play perfectly synchronized across any number of players regardless of the hardware or operating system at the other end.

This add-on is available for Windows, Android and several System on Chip hardware products running on Samsung Tizen, LG WebOS and various displays from Philips, Panasonic, and Elotouch.

Who is this add-on for?

Here are some examples of applications that can benefit from synchronized players:

  • Train and metro stations where screens are installed in a large atrium. This would also apply to airport terminals, bus stations and other similar venues.
  • Conference centers, trade show halls.
  • Shopping malls, food courts and other public spaces.
  • QSR Restaurant chains and fast casual restaurants who use multi-screen digital menu boards.
  • Sports stadiums and cinemas.
  • Automobile dealerships, banks and other retail locations.
  • Any large venue where groups of screens can be viewed from multiple vantage points.

Are there other benefits?

  • Synchronized content can be more engaging and have a positive impact on viewer’s perception.
  • Using individual players in a multi-screen installation provides a simple and robust solution. Let’s consider a situation where multiple screens are connected to a single PC. If the PC driving the show goes down, all connected screens go dark. In this instance having one player assigned to each screen provides redundancy. If one player goes down, only one screen goes dark.
  • Replacing a PC with multi-video outputs is more time consuming than swapping out a small Android based media player.
  • Multi-output video cards and high-end PCs tend to be expensive and more complicated to set-up than Android devices or System on Chip displays.
  • Multi-screen/single PC scenarios also require long HDMI cable runs, or video distribution networks that run on video over Cat-5 or fiber.
  • Video distribution networks require many components, such as hubs and signal repeaters that add more points of failure, complexity and additional costs.

It’s safe to say, multi-player synchronization is a very useful feature that can enhance the audience experience.