23 Nov 2010IPTV standards

Over the past few years IPTV[1] has grown at a phenomenal rate and is rapidly establishing itself in the mainstream. ISPs see IPTV as a key service differentiator and many are banking on it as a key source of revenue. In Europe IPTV is already well established with a subscriber base of millions of customers. YouView (previously Project Canvas), a collaborative venture between several UK broadcasters and ISPs, promises to bring IPTV to the masses in the UK. In the US, Verizon and Comcast already have significant IPTV offerings and China is making a concerted push to roll out IPTV nationally.

IPTV is a unique service because it sits in the intersection between consumer electronics, entertainment, broadcasting and network services. As a result of this, many standards bodies feel they have a stake in IPTV and hence IPTV standards abound. This report focuses on the most significant standards bodies and seeks to give an overview of how their standards interact.

IPTV offers three main modes of operation:

• Unicast realtime streaming to deliver Video on Demand. This allows a user to choose a programme to watch and immediately start viewing it.
• Unicast download for time-shifted viewing. This allows the user to download content in advance for later viewing. Typically this may be done in parallel with viewing a streaming programme, for instance downloading the next episode of a series whilst you watch the current episode.
• Multicast live streaming broadcast. This allows live events such as football matches to be viewed over IPTV. The content has to be encoded “on the fly” and distributed out to all the viewers simultaneously.

These modes of operation highlight the differences between IPTV and traditional TV. In traditional TV systems only broadcast is possible, with all users watching the same content. Broadcast is possible with IPTV it is one of the harder challenges technically (since the Internet is not optimised for multicast). On the other hand IPTV is ideally suited to providing Video-on-Demand services, and as long as the access network is fast enough it can deliver this at broadcast quality. Both technologies allow content to be time-shifted by adding a PVR (personal video recorder), but even then in a broadcast system you are still restricted to watching the programmes that have actually been broadcast.

Although still in the early stages in terms of commercial deployment, IPTV is not new. ATIS has defined 3 generations of IPTV. First generation is simply an augmented version of traditional linear broadcasting, but delivered over the Internet, not via cable or aerial. Typically, a first generation IPTV system might utilise a set-top box (STB) with a built in personal video recorder (PVR) to allow programmes to be recorded or paused. Second generation IPTV adds on-demand programming to this. Users can now select what they want to watch and when they want to watch it. The appropriate programme can then be streamed to them from the central server. Third generation IPTV could be described as personalised TV. As well as being able to select what you want to watch and when, you will also be able to interact in other ways such as uploading reviews or even your own content.