DIGITAL MEDIA HAS UNDERGONE A REVOLUTION IN the last few years. From being the purview of a chosen few, it has now become the playfield of many. Consequently, certain segments of technology have become quite pervasive, even down to the consumer level. On other fronts, certain markets have yet to take off. Truly now, the application spaces for digital media are vast.

Video-on-demand (VOD) has been the catchphrase for digital broadcast. However, the true VOD services have been available only over selected areas of this country. These have been traditionally audio-video content but will now have to move towards a more generic audio-visual content. The ever-burgeoning IP networks have changed the contribution and distribution models and now provide stiff competition to the traditional broadcast networks. “Video over IP” is the current general buzz. It may now be more possible to get closer to the dream of “desired content, anywhere and anytime”.

Digital media presently has a strong foothold within the home. The proliferation of digital cameras has changed the way media is dealt with at home. More homes are now armed with a personal computer and a printer – the scenario of home-brewed multimedia running rampant is more the reality than before. Given the recent introductions of digital SLR cameras, the need for better image, video and audio compression technologies (and implementations) becomes rather imperative.

Digital Broadcast
A new digital video standard (Advanced Video Coding, H.264, MPEG-4 Part 10) is in the process of final completion. As compared to the other international standards, it brings in more compression efficiency. In other words, for the same bandwidth usage, one is able to get a better visual quality. For the same storage capacity, one is able to store more content, perhaps, at even better quality. However, the implementation complexities of the encoder and decoder are quite large as compared to the previous standards. Various attempts at complexity reduction for ASIC as well as software implementations are in the works. It is expected that these new encoders will begin seeing deployment towards the middle of next year, providing some impetus to the broadcast industry towards providing better pictures to the home.

IP-enabled networks (wired and, to some extent, wireless) add to the transport alternatives. In parts of Asia and Latin America, IP networks are the fastest growing networks of choice for the delivery of media.

Interactive Rich Media
The traditional linear view of audio-video content has been around for a long time. In this context, traditional television is enjoyed as a “lean-back” experience. Without alluding to games, if the objective is to get the viewer (or more appropriately the end-user) become more engaged in the audio-visual content, then we need to look at a new paradigm for digital media. In this context, the viewer would have more choices in choosing their experiences, which makes the traditional means of interaction passé.

In contrast to traditional television, one can now conceive of content with a mix of video, audio, graphics and text. A screenshot of such a presentation is shown in Fig. 1. The figure indicates an arrangement of an auxiliary video in addition to a main video. Interaction with the scene elements is facilitated by the placement of “buttons” in the scene. In the example in Fig. 1, the buttons indicating up and down arrows are used to scroll through the preview video windows. The buttons on the right of the screen control the playback of the audiovisual content in the main window. In this particular presentation, the end user also has the option of projecting the video in the main window over the entire screen. In addition to the regular audiovisual programs, the layout also allows for the placement of advertisements and text information, as indicated in the figure.The challenges in content creation are now that much larger but serve to differentiate one offering from the next. The “games” folks have always known about this. The technologies exist to move the paradigm from VOD to COD (content on demand). The associated methodologies and standards for content description, summarization and customization are slowly falling in place.

With the proliferation of wired and wireless networks, the content creator today is not really aware of how his or her content is accessed and eventually delivered to the customer. However, he (or she) would want their creation to be experienced in a manner as consistent with their vision. The separation of description and presentation is a powerful one.

The flexibility in being able to deliver the data over a diversity of networks is particularly appealing to the content creators and content providers. Towards achieving interoperability across the producer-consumer chain, standards for packetization and delivery of MPEG-4 contents over standard cable networks as well as other IP-based networks are in various stages of development and testing. With the diversity of presentation devices (cell phones, PDAs, PCs, set-top boxes) and environments (enterprise, home, roaming), it is expected that interoperable sets of technologies will be leveraged to enable the seamless distribution of interactive contents across these networks to these multitude of end devices.

Convergence On the Consumer Front
On the consumer front, the trends traverse all the way from content creation to content presentation. Digital cameras (still as well as movie) are in large demand and are very affordable. Digital SLR cameras are emerging in the market and are expected to become affordable very soon. These come loaded with features like storage and multi-format playback, compression of audio, video as well as image content, on-board picture processing features, scalability of presentation (from high resolution to low resolutions), and so on. Extrapolating from these data points, the next generation of cameras will have higher resolutions, better compression (AVC, perhaps), more storage and more transcoding features.

The above leads to a natural segue into the topic of content authoring. The creation of home movies is on the rise. The quality distinctions between consumer and professional grade authoring are becoming blurry. Low cost and yet very good authoring packages are widely available in the market as are the companion players. To enhance the media, authoring packages with quality processing capabilities are always in demand. Cutting-edge video and audio compression tools are, its core components. The open source community has been amongst the forefront of such activities and will continue to do so.

The perfectionist at the home is now not satisfied by a linear experience. Consider the layout shown in Fig. 2. Videos of a climbing trip to the Yukon are now augmented with historical and geographical facts and an inviting layout that includes some graphics, text as well as intermixed audio and voice-overs. The multiple video windows may be replaced with slide shows instead. The presentation template may be customized for each trip to give the appropriate look-and-feel.

The “digital home” is becoming more of a reality today. This is also the case in other parts of the world. Wired and wireless home networks are de facto–however, to a large extent, today they are limited to web accesses. But, it is not difficult to imagine the home theater being a part of a home multimedia network, in the very near future.

In this framework, the traditional (digital) set top box may now be either a hub, separating the home network from the outside, or just a node within the home multimedia network.

Stretching the imagination a bit further, the following are worthy of some consideration:

“Digital Film”–oodles of data are being stored on home disks. Data description and characterization becomes key for storage and retrieval. Else this would be akin to negatives being stored and not being used–because the ability to rapidly retrieve the necessary data was non-existent.

Esoteric home appliances: security cameras (not as esoteric), robot helpers, audio-visual aids for cooking and home repair, adaptable devices, and so on.

Neighborhood reality shows–one’s imagination boggles at thought.

Interoperability and Intellectual Property Issues
Given the ubiquitous connectivity framework, it is reasonable to assume the scenario of content proliferation in different formats. For “seamless” movement across the networks and consumption by the user, a large measure of interoperability is desired. This can be achieved in two ways: •a single proprietary format all the way across, or •vendors conforming to a set of open standards.

It is quite necessary that the number of standards in the mix be kept to a reasonable minimum. However, given the formats already in the mix today, it would be more reasonable to assert that there will be programs in place to transcode from one format to the other according to the specifications of the user and the end devices.

Intellectual property issues are a touchier one and deserve more than a passing mention. Digital content can now be replicated without any appreciable loss of quality and therefore, multiple regenerations of the content are virtually as good as the original. This, of course, does not account for processing losses, if any. Over the last few years, the issue of replication of content has led to an enormous debate on content ownership and fair use, among other things.

Localizing the discussion to the home, new business models are needed for home services so that the rights of the content creator as well as that of the content consumer are taken care of adequately. Issues such as making copies of legally acquired content for private use need to be satisfactorily addressed without resorting to legal edicts.

Future Evolution
Of course, there are aspects of digital media with usage scenarios other than entertainment. Given today’s state of the world with a perceived heightened need for security for human life, digital media (audio, video, images) technologies are being groomed for intelligence purposes.

Homeland security is the impetus behind these initiatives and is driving the development from highly miniaturized sensors to algorithms and systems for object segmentation, identification and tracking. Cameras attached to facial recognition systems have been deployed in some parts of the world to varying degrees of success.

In summary, the prospects for digital media are immense. The application space is now much wider than before, and with the proliferation of digital networks, it should now be more possible to approach the realistic “utopian” model – “content anywhere, anytime … at a reasonable price.”

Ganesh Rajan is the Director, Advanced Technologies at iVAST where he provides technical leadership on end-to-end MPEG-4 platform including future extensions into MPEG-7 and MPEG-21. Rajan has been involved with MPEG related activities since early 1996 and is the co-editor of ISO/IEC 14496-1 (MPEG-4 Systems) specifications. He received his Ph. D. degree in Electrical Engineering from the University of California, Santa Barbara, in 1987.