Multimedia and Collaborative Computing

Jerry Kellenbrenz, Apple


The advances in multimedia and communications technology are starting to meet the underlying needs for individuals to effectively interact in a collaborative manner from dispersed locations. An early sampling of collaborative work is:


The tools for authoring multimedia material and the infrastructure for displaying and interacting with the information amongst dispersed groups of people are in the advanced development state.

With authoring tools such as: Apple's OpenDoc, QuickTime, QuickTime VR, Quickdraw 3D, Apple Media Tool; Macromedia's Director, Shockwave; Adobe's Photoshop, Illustrator we are able to develop multimedia material composed of varying media objects/applets. The objects can be text, audio, pictures, 3d animation, movie clips and can have "hot spots" be rotated and zoomed. Many of these tools are supported on multiple computer platforms e.g. MacOS, Windows, UNIX.

The authored material can be deployed and accessed on the Web and used in collaborative computing.

Infrastructure for collaborative computing and interacting with the multimedia material is starting to be deployed; examples are Apple's QuickTime Conferencing, Intel's Proshare, Microsoft's Netmeeting.


A major inhibitor to collaborative computing and interaction with multimedia material is the need to move large blocks of information in an effective manner. This touches on two areas: one, the telecommunications infrastructure to move the information in point-to-point and multipoint configurations in a timely manner. Procedures/standards for more effectively compressing the information or for exchanging only the deltas to the information being jointly developed.

The telecommunications problem, in simple terms, is one of bandwidth and quality of service (QoS).

Some of the telco oriented forums are projecting that bandwidth access to basic telmedicine, high quality video Conferencing, and Web site hosting applications requires up to 1.5 Mbps, symmetrical bandwidth. General consensus is that for basic audio/video/whiteboard teleconferencing 300 Kbps bandwidth is required. Within many corporate Intranets this is possible. However for most individuals in home, small business, road warriors they are limited to telephone facilities of 9.6 to 28.4 Kbps. Even with those fortunate to have ISDN lines which when using both b-channels for a bandwidth of 128 Kbps is not adequate for basic audio/video/white board conferencing.

There is hope for change in the US with deregulation allowing telcos and cable companies to compete. They are experimenting with Cable Modems and "Asymmetric Digital Subscriber Lines" (ADSL) technology which will bring the needed bandwidth to the wired users. Access for the nomadic user (wireless) is still open.

The other part of the telecommunications inhibitor is QoS. The streaming of video and audio has timing constraints which if not adhered too is disruptive in a collaborative computing or Web accessing environment. With today's switched data networks the time constrained real-time procedures are not present. Compounding the QoS problem is the evolution and concatenation of different network technologies. The network topology between the end users could be composed of a10 Mbps Ethernet to ADSL to ATM backbone to a gigabit switch to 100 Mbps Ethernet with IP routing.

QoS, in topologies as indicated above, is the area alliances/forums/standards groups can help. Work is starting within these organizations to address the QoS with "Reservation Protocol" (RSVP) "Multicast Backbone" (mbone), "Transport Protocol for Real-Time Applications" (RTP), "RTP Profile for Audio and Video Conference with Minimal Control" (RTPC). These protocols need to be verified and supplemented as needed. As a means of verification extensive deployment of these protocols and Interoperabiltiy experiments with varying network topologies is required.

In summary: the need for multimedia content on the web and in a collaborative computing environment is there. The standards and tools for building multimedia content are progressing. The major inhibitors for deployment are bandwidth and QoS for moving multimedia content.

Bandwidth needs to be addressed by the physical network providers. QoS service needs to be addressed by standards/specification developers in conjunction with the physical network providers.