SMIL is based on XML and, like HTML, it is a markup language. It was created to play multimedia content (audio, video, images, etc.) synchronized in time. The W3C standardized the first version in 1998 and expanded in the following years. The current standard in version 3.0 was approved in 2008.
A first major industrial application of SMIL was in HD-DVD and MMS. However, the language did not have a real breakthrough. It was not until 2008 that the Taiwanese company IAdea discovered the language for its products and began to develop digital signage SMIL hardware players. Since then there has been a kind of Renaissance.
For the industry, this was the first important step towards reducing dependencies. If someone wanted to operate a digital signage network before, he had to buy the server component (CMS) and the client software (media player) from a single source. Thanks to a uniform SMIL standard, it was now possible to use components from different manufacturers for this purpose.
Like HTML, SMIL is a registered industry standard. Just compare it to a web page: if it is in compliance with the standard, you can use any web browser. Mozilla, Chrome, Internet Explorer, Opera, Safari – no matter which page you go to; it is usually displayed in the same way except for a few small things. The same goes for the Digital Signage SMIL players.
What does SMIL do?
SMIL has been tried-and-tested, it is robust and offers many functionalities.
- Circular playlists for endless program loops. This is the primary form of presentation of digital signage e. g. In a shop window, shopping malls, waiting rooms, etc….
- Time-controlled playlists. Like a TV program, you can plan content in advance and play it at specific times.
- Shuffle playlists, e.g. to display a different news feed for each loop pass
- Multiple zones, e.g. for news ticker/text scroller
- Control multiple screens simultaneously
- Interactions for kiosk systems or lectures
- Different media such as videos, pictures, texts and web pages can be linked efficiently via networks (mashup)
- There are XPath functions and expressions to make playback decisions dynamically at runtime
- Expandability through custom tags for e.g. Index updates, logs or configuration commands
- Bandwidth controlling to keep network utilization low
What doesn’t SMIL do?
The language is general in nature and only describes how multimedia content is presented. Of course, it was not specifically designed for digital signage networks. That’s why some relevant features are missing::
- A pull mechanism to check periodically, whether playlists have changed
- Handling logs or play reports
- Remote administration and configuration functions, e.g. Reboots volume or brightness adjustments, etc.
Manufacturers may use these functions differently.
Anyone can develop SMIL Components?
Due to the openness of the standard, the expandability and the publicly accessible documentation on the websites of the W3C, any software developer can theoretically develop SMIL-compatible software components (player, CMS). There are no obstructive patents or the obligation to sign non-disclosure agreements. Thanks to the existing language features, SMIL can prevent the programmer from making wrong decisions about the control language design.
What does the developer reality look like?
According to a study by the industry portal Invidis from 2012, more than 120 providers in Germany alone offer digital signage solutions. More than 60% of these are smaller companies.
Many projects only start as an ancillary business with a minimum requirement profile. For example, because an important existing customer of an advertising agency requests only to play media in an endless loop. At this point in time, the company usually has little or no digital signage experience. In the apparently simple implementation of customer requirements, coupled with the usual price and time pressure, decision makers often neglect conceptual sustainability. The main thing is that the important customer will be happy. Both the control language and the software go quickly and easily in the hand. As time passes, the requirements increase because of success, customer requirements, and technical innovation required. For example, the implementation of differentiated time controls.
This is the point where the probability of maneuvering into a technical dead end, which may become noticeable much later.
Eventually, a functional request comes up and during the realization, it becomes apparent, that the easy way was already blocked at the beginning of the project by a premature design decision. If time and manpower are lacking, complex workarounds have to be implemented. This often leads to side-effects in the code, which are difficult to locate. The system becomes more unstable, error-prone and the cost for maintenance and implementation of further functionalities increases immeasurably.
The scenario, of course, is not specific to digital signage. SMIL will not relieve us of the need for good quality assurance, communication and documentation. The management must also have an understanding of these lengthy processes. But at least we need to deal with one elementary problem less. SMIL already provides a sophisticated control language for our digital signage projects. Why reinvent the wheel?
Specialized service providers and full-service providers
The standardization of SMIL enables specialized technical service providers. These may relate exclusively to one component, e.g. just the CMS, or as in the case of IAdea focus on hardware players. Without having to offer a complete solution, even smaller companies can reach the market faster with their innovations and new ideas.
The result is diversification. As even full-service providers can assemble their customized products more easily from a wider range of technical solutions.
Where can I get digital signage SMIL components?
The best-known suppliers are IAdea and Qbic International for about 2 years. Both companies openly document their functionalities at http://a-smil.org and http://open-smil.org. Planar and ViewSonic are two further companies which offer SMIL compatible players. In Germany, the company Isaria distributes its own developed digital signage SMIL Player based on Android for your projects.
There are a number of available software players that partially understand SMIL 2.1, e.g. Real Player or QuickTime and also the fully SMIL 3.0 compatible Ambulant. But all these players are not customized to the needs of the digital signage market. They lack the functions described above.
For these reasons, I decided in 2016 to develop a player called Garlic. This is available to anyone under a free license.
Content Management Systems
There are some CMS service providers who offer SMIL as an option or as an entry-level option. E. g. Easyscreen, Scala, Signagelive, Stinova, etc.
My company SmilControl has exclusively committed itself to SMIL with its CMS of the same name. We are convinced that the flexible combinability of technology modules will prevail in the long term.
Conclusion for Digital Signage SMIL
After HD-DVD and MMS are relics of the past, the language SMIL had a shadowy existence for a long time. It is only in their incarnation as Digital Signage SMIL that their significance grows again. With the exception of a few additional features, it supports our application profiles optimally. Their use opens up new markets and opportunities, even for smaller specialized suppliers.