DMV (Digital Media Viewer) 
        - Specification for Media Fusion Terminal Platform

                        Hiroyuki Nakano, Digital Vision Laboratories

Televisions in the near future will have more and more interactivity.  
For example, broadcasting HTMLs along with TV signals has already been 
started.  That means a TV set must run a Web browser, in order to 
benefit from this new service.  Other examples of possible interactivity 
associated with TV are games, Electronic Programming Guides (EPG), and 
controlling other audio/visual devices such as VCRs.  These 
interactivities can be implemented easily as software, if TVs in the 
near future become "application platforms", on top of which application 
software run.

Digital Vision Laboratories (DVL) is proposing a specification named DMV 
(Digital Media Viewer).  DMV specifies a set of functions which home 
terminals (e.g. TVs or settop boxes) in the near future should have, in 
order for them to host certain types of application software.  This set 
of functions is specified as a set of API (Application Programming 
Interface), which application programmers can use to write their 
software for DMV compliant terminal platforms.  

If DMV specification is widely accepted, many benefits are anticipated.  
For application developers, they can port their software easily from one 
DMV compliant platform to another, thus increasing their productivity.  
For platform vendors, their products can run more interactive 
applications if they follow DMV specifications, thus increasing the 
value of their products.  For service providers (e.g. TV stations), they 
can expect a large base of terminal application platforms which have 
certain set of functions, so they can easily start new services which 
use these functions.

Another aspect of DMV specification is that it is a specification for 
"media fusion terminal platform."  Currently many kinds of digital media 
are looking for a place in home.  They can roughly be categorized into 
three, namely,

        Broadcast media (e.g. digital TV)
        Package media (e.g. DVD and DVD-ROM)
        Network media (e.g. Internet)

If application platforms with certain functions widely exist as 
terminals at homes, there are many possibilities of creating new 
services, by combining these media.  The HTML broadcast service which we 
previously mentioned is just one example.  We believe carefully defined 
specification for home terminals will help these "media fusion services" 
to emerge.

We defined DMV specifications based on three reference services.  The 
three services are following.

        HTML broadcast
        Multimedia EPG
        Games linked to TV contents 

We chose these services because they are expected to be important as 
interactivities added to TVs in the near future.  

By studying above services, we identified the key requirements for 
platform functions.  Among key requirements are:

        High speed graphics capability
        Internet connection capability
        Audio/Visual Devices control capability

Then we defined API for access to key functions of platforms, and other 
utility functions which are required in writing applications.  Our API 
provides access to following functions of a platform.

        Operating system
        Graphics hardware
        Sound hardware
        Input devices
        Network (Internet)
        Audio/visual devices (such as VCR)

We also implemented several prototypes of DMV compliant platforms.  In 
the most recent prototype, the hardware consists of 32 bit RISC CPU and 
16 MB of memory.   The operating system is a commercial real-time OS, 
and we wrote libraries which implement API functions on top of the OS.  

For our prototype platforms we developed following applications:

        Web browser
        AV Email (E-Mail client which sends/receives images and sounds)
        EPG (user interface only)
        Video editor
        2D game

By implementing these prototype platforms and applications, we found 
that our DMV specification includes most of key functions for 
implementing the reference services.  We also found that application 
software on top of DMV API is highly portable between prototype 
platforms.

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Hiroyuki Nakano
Digital Vision Laboratories Corporation, Tokyo, Japan
hnakano@dvl.co.jp    +81-3-5411-9829 (phone)  +81-3-5411-9838 (fax)