DVD On Demand: The Streaming DVD Experience
    (4/2003)

    by Douglas Dixon

Media Quality
Playback Experience
Interactive Experience
DVD on Demand
References

What we know and love as "DVD" keeps adding more dimensions -- consumer electronics and computer, set-top and desktop, players and recorders, interactive experiences and creative authoring. Of course, DVD is at the core a disc media format, yet its most important aspect for the mass market is the movie-watching "DVD experience," combining high-quality content with interactive navigation and alternate presentations. The power of the DVD disc, the physical media, has been the ability to provide this kind of experience in a convenient transportable package, with high confidence that any viewer can enjoy the full experience on a wide range of players, from set-top to portable to computer.

In comparison, while Web sites and streaming media are dynamic and sexy, and can be rapidly updated with new information, the actual streaming experience is heavily constrained by the limitations of the available Internet connection and bandwidth. As a result, streaming media has been used primarily as a linear playback medium, too often providing a less than satisfactory experience characterized at best by small video windows and reduced frame rates, and at worst by stuttering playback and sluggish response times.

However, this picture has changed significantly with the latest generation of streaming media formats, which combine yet another major advance in compression technology with even stronger support for interactivity. As a result, the apparently obvious differences between DVD and streaming media are becoming more blurred. After all, if what we know as "DVD" is about the interactive experience, delivered in an integrated package, then it does not necessarily need to be delivered on an optical disc.

Media Quality

What, than, are the key components of the DVD experience? Clearly, it starts with the content: high-quality video, surround-sound audio, images, and text. DVD also provides interactivity, with menus to navigate among different collections of content, as well as chapter points to facilitate jumping directly to sections of interest. DVD then adds another dimension of content and interactivity, with multiple parallel streams of video, audio, subtitles, and graphics. In addition, the interactivity is not limited to choosing which piece of content to play, but also includes switching dynamically between segments and streams during playback, and even the ability to program customized or even random playback and overlay effects for subtitles and graphics.

In terms of quality, the latest generation of streaming media formats introduced in 2002 has taken another major step forward in providing high-quality compression at broadband data rates. Both RealNetworks RealVideo 9 and Microsoft Windows Media 9 now scale not only in bitrate from dial-up to broadband and beyond, but in picture resolution across the full range from handheld displays up to high-definition video with multi-channel surround sound. Streaming formats now can deliver "near-DVD" quality at around 500 Kbps rates for broadband, and visually lossless compression quality as low as 2 or even 1 Mbps.

These advances have made streaming video on demand and download movie rental services commercially viable over broadband connections. RealNetworks' consumer subscription businesses reached over 900,000 paying subscribers by the end of 2002. The RealNetworks RealOne SuperPass service offers subscription programming for $9.95 a month, including PGA golf, Major League Baseball, NBA basketball, NASCAR racing, CNN, ABC news, and iFilm videos. Meanwhile, Windows Media Player 9 provides built-in access to premium services including PressPlay and CinemaNow, which offers streaming or download rental of hundreds of movies for as little as $2.99.

Meanwhile, the standards community is also advancing compression quality. Of course, MPEG-2 has been a tremendous success for DVD and digital television. The next step, the MPEG-4 format, was approved in 1999. It provides not only better scalable compression but also explicit support for interactive multimedia across networks. MPEG-4 is currently being extended to provide substantially higher video quality, under the name Advanced Video Coding (AVC), also known as ITU H.264 / MPEG-4 part 10. The MPEG-4 Industry Forum includes more than 100 companies working to further the adoption of the MPEG-4 standard. And Apple's new QuickTime 6 features MPEG-4 as the mainstream format for video delivery, and saw more than 25 million downloads in the first 100 days after it was released.

This improved compression creates a significant paradigm shift for working with video, with full-quality video at data rates around 1 Mbps (as opposed to 6 Mbps for MPEG-2 on DVD or 25 Mbps for DV). It is now feasible to store hundreds of hours of video on a typical hard drive, tens of hours on a DVD disc, and even a couple hours on a CD. For example, just as many CD audio players now support MP3 format, Windows Media format is being built into over 200 consumer electronics devices including set-top DVD players, to allow more hours of audio and video to be stored and played from a single disc or device.

Or if you want a packaged viewing experience on disc, Microsoft is partnering with Matsushita Electric (Panasonic) and Fujifilm to evangelize the HighMAT (High-Performance Media Access Technology) format. HighMAT is designed for burning music, video and photo collections from a PC to recordable discs in a format that can be played and viewed on a wide variety of consumer electronics devices, ranging from car stereos to CD players to DVD players.

Playback Experience

But even if you can stream high-quality video to provide linear playback over broadband, a DVD-like experience requires interactivity, and in the context of a packaged and reliable experience. These new streaming formats do provide a better and more reliable experience, even delivered over the arbitrary connections of the Internet.

Apple, RealNetworks, and Microsoft have upgraded their streaming formats as end-to-end systems, building tolerance for network hiccups into the compression / decompression algorithms (codecs), compression tools, servers, and players. Servers and players can work together to dynamically adjust to the currently available data rate (i.e., by selecting from several available streams), and players and codecs can accommodate intermittent packet loss and dropped frames (i.e., by varying the frame rate and even synthesizing in-between frames). Of course, while these measures can hide transient problems in an Internet connection, the broadband experience still cannot compare to the reliability of playing directly from a local DVD disc.

In addition, these systems include "instant-on" technology that minimizes the agonizing wait when starting playback of a new stream (as the beginning of the stream is downloaded and pre-buffered for playback). This improvement also means that it is now feasible to dynamically switch streams during playback (given adequate bandwidth), much like switching between alternate tracks on a DVD.

Interactive Experience

And what about interactivity? Of course, the Web is interactive, with dynamic HTML and Flash animations (and those wonderful pop-up ads). But a DVD-like experience is about interactive audio and video playback, not just clicking an animated button to start playing a video clip in a separate window. DVD is an authored, packaged experience, more like an entire rich content application created in an application like Macromedia Director and delivered over the Web through the Flash player.

The streaming community is developing several approaches to providing a choreographed and integrated interactive Web experience. The Synchronized Multimedia Integration Language (SMIL, pronounced "smile") is designed to support simple authoring of interactive audiovisual presentations, providing for animation, layout, and synchronization of objects in space and time (and layers) over. Various versions of SMIL are supported by the RealNetworks RealOne Player and Microsoft Internet Explorer 5.5 and 6.0.

The MPEG-4 standard goes even further, to encapsulate not only multiple media objects, but also their interactive behavior, into a packaged stream. MPEG-4 supports video, audio, text, graphics, and other synthetic content. It permits video streams to be decomposed into multiple objects (i.e., as foreground and background layers). It then provides tools to create a unified production by animating the behavior of these objects over time, and then delivering the result as an interactive experience.

Instead of packaging the entire experience into a single stream, Microsoft and RealNetworks are encouraging developers to coordinate integrated multimedia through the use of programming interfaces. In this way, video can be embedded within Web pages, user actions on the page can change the video (changing or switching streams), and timed events in the video can cause updates on the page (such as displaying associated subtitles or illustrative animations).

If you do want a more packaged experience, Peter Gabriel's recent album, "Up," debuted on the Web in Windows Media 9 format as a 188 MB download. The free one-week preview played the album in 5.1-channel surround-sound, plus displayed the lyrics and provided links to additional material.

DVD on Demand

These continued improvements in video compression technology, combined with the explosion of options for creating integrated multi-media Web-based streaming presentations, are bringing DVD-like experiences to the Web. The technology components are in place, but the interactive content is still in its infancy, as the content creators are beginning to explore the possibilities and the tool developers are creating the authoring and playback software to enable those possibilities.

Even so, the compelling advantage of the DVD, for both viewers and content developers, it that is a hugely popular single standard for packaging up a viewing experience. As a result, DVDs can be played across a wide range of devices, with high confidence that the viewer will experience the full quality and interactivity of the author's intended design.

But what happens as the streaming experience continues to improve, and consumers are able to order up a "DVD on Demand" experience over a cable or Internet connection, complete with menus, additional complementary material, and alternate views? If consumers come to call this experience a "DVD movie," the meaning of "DVD" itself may change, as it becomes a generic term for a Digital Video Dynamic experience.

References

Apple QuickTime - QuickTime content and Player
    www.apple.com/quicktime

Apple QuickTime - Developer information
    developer.apple.com/quicktime

Microsoft Windows Media - Windows Media content
    www.windowsmedia.com

Microsoft Windows Media - Windows Media Player and tools
    www.microsoft.com/windows/windowsmedia

Real Networks - Players and content
    www.real.com

RealNetworks - Technology and tools
    www.realnetworks.com

Synchronized Multimedia Integration Language (SMIL)
    World Wide Web Consortium (W3C)
    www.w3.org/AudioVideo/

MPEG-4 Industry Forum (M4IF) - MPEG-4 technology, products and services
    www.m4if.org

Internet Streaming Media Alliance (ISMA) - Open standards for streaming rich media
    www.isma.tv

Moving Picture Experts Group (MPEG) - MPEG compression standards
    mpeg.telecomitalialab.com -> 
    www.chiariglione.org/mpeg/standards.htm

Envivio - Tools for MPEG-4 streaming and broadcast
    www.envivio.com

iVAST - Creation and delivery of interactive and enhanced rich media experiences
    www.ivast.com

HighM.A.T. - High-Performance Media Access Technology
    www.highmat.com

(Originally published in Mediaware Magazine. March/April 2003.)
Copyright 2003 IRMA/Mediapar Reprinted with Permission