In the past, we were frequently asked if there was a difference between SMIL and HTML and whether HTML could also be used for digital signage. In this article, you will learn why the question is wrong in itself, and how both technologies can be used perfectly when used correctly in our business.
Different Concepts
HTML stands as abbreviation for HyperText Markup Language and SMIL for Synchronized Multimedia Integration Language.
Both HTML and SMIL are text-based markup languages and are based on XML. Both have a similar structure, with head, meta, body, and are standardized by the W3C, and have some similar elements. However, the similarities end there. The main difference lies in the concept:
SMIL places the spotlight on the synchronization of zones with multimedia content.
HTML focuses on structuring and linking text as well as multimedia content
SMIL synchronizes content in Zones
SMIL opens up many possibilities to create automated and interactive presentations from different multimedia content. In this case, we name them digital signage playlists because automated presentations from our industry are more like music and video playlists from radio stations, TV stations, MP3 players or software like the VLC player.
While conventional playlists merely play content sequentially or randomly, at best, SMIL playlists include functionality to change the flow in an event-driven manner. A defined event that launches a specific reaction such as the playing of images, videos or nested playlist is what we call a trigger.
There are several interactive and automatable ways for triggers to control a flow.
Time-controlled at a specific date/time.
Interactions: User presses a button, touches the screen, clicks the mouse, or scans an EAN code.
Event: An image or video starts, ends or repeats a certain time.
The content can be assigned to individual regions. For our industry, regions essentially mean dividing the available screen area into overlapping zones. A screen area can also consist of many monitors. Each business or company has a different naming. We refer to this capability as the multi-zone concept, others may refer to it as layout regions. Video editing systems and graphics applications often use the term layer.
HTML links Content
HTML structures multimedia content in the same way as a Word document. Furthermore, it provides the possibilities of connecting them with each other through links and jumping to different points. The authors of the HTML document determine sections, articles, lists, tables, headings, paragraphs, images, videos, highlighting and other semantic elements. Users therefore navigate through different sections and documents.
There is no option in HTML for a flow control that can be automated. Modern HTML is not even intended to serve as a visual representation. An additional technology called CSS (Cascading Style Sheets) is responsible for that. This was different in the past, but these legacy functionalities like center, font, or marquee are gradually disappearing from the specifications.
To summarize: HTML formats a document and SMIL formats a flow list.
In addition to HTML and the layout language CSS, web browsers also support a programming language called JavaScript. With this combination, you can develop impressive interactive applications. This includes websites and portals as well as full-blown software such as mail programs, word processors, drawing programs, spreadsheets and more.
The Symbiosis to Success
SMIL and HTML stand for wholly different purposes and cannot be compared with each other. There is no “either or” in this case, but an unconditional “and”.
The ability of HTML, CSS, and JavaScript allows developers to create special interactive applications with little effort. These work platform independent in any web browser or web component. We treat these applications as separate entities and integrate them into our playlists. This makes applications controllable in the same way as images or videos.
The article on Digital Signage Widgets explores this topic in more depth. Using, controlling and positioning web pages and widgets within a SMIL playlist using layers brings the benefits of both worlds together. In this way, an ATM or info terminal can additionally display advertising or other information.
Media player in the Web Browser
Due to the power of JavaScript, a so-called digital signage player can also be reprogrammed with JavaScript. Some companies are already doing this to seemingly cover multiple platforms more effectively. Presumably, this also represents the origin of the question about the difference between SMIL and HTML.
However, this does not change the fact that HTML is not suitable as a storage format for digital signage playlists. n addition to the disadvantages, a browser player also needs a format with the same properties as SMIL to store playlists.
