HTML5 has emerged as the focal converged platform for app development across the whole multimedia ecosystem including TV, even though a number of CE devices still do not support it. This was highlighted by the launch of an HTML5 TV app by music streaming service provider Pandora, aiming to generate more sales from users on big screens, which has anyway been a growing trend. Pandora developed an HTML5 player in the expectation that the whole CE ecosystem will coalesce around it.
Rival Spotify, while not specifically targeting TVs at that stage, has been encouraging third party app developers to integrate HTML5 apps into the desktop music streaming service since late 2011. This enabled users to access apps written in HTML5 from their Spotify clients, rather than run them directly on an HTML5 player.
The objective of HTML5 is to provide a clean player environment for all multimedia apps and services, that avoids the need for plugins or APIs for specific functions, as is necessary for Adobe’s Flash or Apple TV. To do this HTML5 has added support for video and audio elements as well as scalable video graphics and mathematical formulae, within the markup language to enable functions that would have needed plug-ins with earlier versions of HTML. Another important addition is the Document Object Model (DOM) facilitating interaction with multimedia objects such as images, graphs and video clips represented in other language environments such as XML and XHTML. But the ultimate idea is the old dream of write once and play anywhere, rather than needing different apps for say Android and iOS.
More recently HTML5 has gelled with other key components of the IP video ecosystem, notably DASH streaming and encrypted content control. These two vital ingredients had been missing from HTML5, but have been added in different ways. DASH was a separate development ushered in by MPEG to create a harmonized streaming standard to optimize quality and enable efficient video distribution over unmanaged networks. It is linked with HTML5 via the Media Stream API. Under HTML5 this API enables a stream of audio or video to be handled as an object specified as a URL string, which references data stored in a DOM file.
The more interesting development from HTML5’s perspective is the Encrypted Media Extensions (EMS) to allow encrypted content control. As this was lacking in HTML5 as originally specified, Microsoft, Netflix and Google, which are rivals in the video ecosystem, got together to develop EMS as an extension to HTML5’s media streaming capability, to add encryption for protecting copyrighted content.
This initiative avoided encumbering HTML5 with DRM technology and kept it agnostic of any individual security mechanism except for a baseline level of encryption. The idea is that the client simply requests a decryption key to content via standard Java Script. If after the appropriate authentication process that client is deemed to have the rights, the key is transmitted via the simple encryption method that HTML5 now supports. In fact EMS has just been added to HTML5 with the result that it can now be used to deliver premium content. The three original partners gain in slightly different ways. Netflix has been relying on custom client applications or the Silverlight media playback plugin from Microsoft to decrypt its protected video streams. Google has YouTube now offering video rental and aims to exploit the HTML5 extensions there and on Android handsets, while Microsoft runs Zune for PCs and its Windows Phone platforms.
EMS supports various use and service types, with options including simple decryption without the need for any third party DRM servers, and different levels of security including both hardware and software based. Agnosticism is enabled by deferring all information and algorithms about the content decryption and protection solution to the application server and client content decryption module. Related to this is another important property, stream reusability, so that the actual encrypted content stream or file for a given codec can be identical irrespective of the protection and decryption mechanisms used.
The access to DRM and potential for hardware protection are supposed to allay any security fears premium content owners may have over HTML5 based OTT services. But the devil is in the detail of the implementation and it is unlikely that EMS at a stroke will unleash a flood of premium OTT services.