Interactive TV as a concept and technology has had no easy ride, and the industry deserves credit for getting it as far as it has. Barriers to entry are numerous, and returns are minimal.
Once the initial investment is made (several hundred thousand Euros in most cases), applications need to be topical, be exciting and generate the necessary return. In a world so desperately in need of standardization, the original flexibility of the MPEG-2 specification has spawned incompatible proprietary middleware platforms.
The vested interests of those early monopolists who had their products pre-installed on set-top boxes have fatally wounded the community. If iTV is dying, the industry has no one to blame but itself.
Despite its stability and its effectiveness at manipulating low-level hardware functionality, OpenTV is a misnomer for a technology that is anything but open. MediaHighway provides virtual machines for little-used languages (MHEG, Pantalk). The most flexible candidate is Liberate, now owned by SeaChange. MHP is considered too bloated to run on a typical set-top box with the power of a pocket calculator.
As an example, developing iTV content for the UK's digital TV platform is a laborious process that requires months of C code development and quality testing — precisely the opposite of what is needed in a topical, event-driven environment such as TV. WapTV is a genuinely interesting innovation, but the price tag is too high.
It might have taken a while to make the transition to MPEG-4. Now MPEG-7 and MPEG-21 are gaining traction. They define a set of tools to describe multimedia content and a global framework, respectively. This is becoming increasingly important as we move to a ubiquity of digitized assets and the need for their management. MPEG-2 could not last forever. MPEG-4 requires less bandwidth, offers far better quality and provides a considerably more complex model than its predecessor. The price is the need for more processing power and the problem of backwards compatibility with legacy hardware. It's no panacea, but it's a leap in the right direction.
The genuine excitement that has fuelled the hype about IPTV is the merging of Internet technology with the world of television — the endless possibilities for innovation. When I say IPTV, I mean broadcast-quality and -sized video delivered in a controlled way over a private network using Internet Protocol as the transmission medium, rather than just Internet TV, the Internet on your TV or TV on your PC. It's everything MPEG-2 iTV never was — and never could be. It opens and democratizes the living room to all comers.
The growth of high-speed broadband able to support reliable broadcast-quality video streams has given us a platform to communicate and interact in new ways we can't yet imagine. I believe IPTV will see steady, gradual take-up in parts of the world where fiber has yet to run directly into neighborhoods, beginning with deployments of hybrid DVB-T/S systems.
Two things are the lifeblood of IPTV: MPEG-4 as the standard delivery medium (whether it is AVC or WM9) and middleware systems using the mark-up languages HTML, WTVML and XUL (XML user-interface language).
Content delivered over broadband is by its very nature a two-way transaction. That enables operators to uniquely identify viewers and to subsequently personalize services to their tastes and quirks.
HTTP, RTP and RTSP delivery are a fundamentally different paradigm to broadcast transmission. They guarantee delivery. There is no need for data carousels, FEC, expensive distribution equipment or mysterious private API documentation. Preparing a channel for multicast playout over IP is a relatively simple matter of descrambling, transcoding and encapsulating the source media in real time.
The 22-part MPEG-4 standard doesn't explicitly specify a transport system as MPEG-2. (Although it does define a streamable container format into which separate tracks/objects can be multiplexed.) It delivers crisper video, and it can be sent in the way that best fits the application — even by wrapping it in an MPEG-2 transport and using a carousel (for satellite IP networks).
We can encode it in one of many different profiles, encrypt it, tag objects in it with metadata and embed interactivity that should work for any MPEG-4-capable receiver device (as opposed to needing a specific middleware to demystify the contents of a carousel).
MPEG-4 interactivity is based on the now defunct VRML language. It can be authored in textual scripts through converting human-readable BIFS Text (BT) or eXtensible MPEG-4 textual format (XMT) into the object-based binary format for scenes (BIFS).
The Web browser model
Another important factor is the evolution of the set-top box, the centerpiece of the IPTV ecosystem. What we are experiencing is not a revolution, but a phase shift. Two parties are fighting for prime time: Windows Media Center (which IT vendors are putting all their resources into) and thin client devices (which has been the modus operandi of the past). They are both based on Internet technology (typically a browser model, but with TV-specific extensions).
This means rich TV menus and screens can be built from HTML stored on a Web server, just as normal Web pages. Web developers can be cross-trained and existing content easily adapted.
Standardization helps us streamline workflow processes such as content management. (See Figure 1 on page 17.) For on-screen graphics titling, Web applications, mobile interaction and walled garden content for IPTV, we can apply existing and tested disciplines to new technologies and get them to interact with each other in harmony. There is, however, a fundamental issue that needs to be addressed by both commercial management and systems administrators: How do we police the availability of content for STBs?
Central to the success of IPTV is the ability to converge content across multiple devices, and a walled garden will not open the platform or allow for the innovation that will drive uptake. So, how do you maintain security and protection from indecency while allowing the masses the freedom to innovate and, subsequently, grow the service and its community? Access control lists are one answer but are not sufficient. The next question: How do we filter third-party and user-generated content?
The advertising-supported, free-to-air model of television was overtaken by pay/subscription. Transaction-driven programming has now superseded that. The focus in multichannel platforms is now encouraging viewers to use premium-rate services, in the guise of participation. Part of the reason for BSkyB's success in delivering a viable commercial platform for interactive TV services in the UK was its micro-payment system: premium-rate telephony.
This poses a serious challenge for operators deploying IPTV. Billing for pay per view is added as individual charges to a subscriber's monthly bill, but third parties developing TV programming and interactive applications need a way to generate revenue. How do viewers access interactivity when intimately mixed with the content, when they previously just used the red button? The answers aren't clear. However, just as gaming was the most popular iTV application, it is likely that familiarity will be essential for successfully selling to potential viewers.
Video delivery and distribution also bring their own challenges: scalability and quality of service. IP networks are a known quantity and highly configurable, but they were not designed to transmit video. RTP and its control layer RTSP were designed to compensate for this. TCP is by nature an extremely aggressive protocol that continually probes the bandwidth available in order to fill it completely, causing buffer issues that can affect playback.
Preparing a playout network for IPTV requires a multicast-enabled distribution platform that segments IP data into three separate prioritized VLAN channels: voice, video and data. That same architecture, coupled with the latest efficiency algorithms, can help to optimize ways for providing media on demand, which suffers from the age-old problem of costs rising proportionally with customer acquisition. (See Figure 2.)
Change isn't always bad, but it is also not always better. IPTV is the natural evolution from iTV, and despite its capability for disruption, it should not be feared or dismissed. It is the natural fulfillment of a powerful and compelling paradigm that started with the birth of viewer interaction and now needs time to breathe and spread its wings. HTTP was a simple concept, but it has given us the Internet we know today.
Alex Cameron is managing director of Digital TX.
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