Summary
CU-SeeMe desktop videoconferencing
software is a peer-to-peer and client/server technology that allows interactive
multiparty video and voice communication over the Internet or any local
TCP/IP-based network. Beginning as a collaboration with the Global Schoolhouse
in 1993, the goal of this project was to provide very low cost face-to-face
audio and video connectivity to the largest possible number of users and
enable a social experiment of global proportions. Running on popular desktop
platforms with full cross-platform connectivity and no proprietary hardware,
CU- desktop videoconferencing technology established a new price-point in
cost and a new paradigm of availability, quickly becoming the world's most
popular videoconferencing platform. Today, millions of users worldwide in
over 40 countries and on every continent including Antarctica use this software
on a daily basis. CU-SeeMe is on desktops in gradeschools, in businesses,
and in national laboratories often with connections between them. Furthermore,
business partnerships have successfully transferred this technology to the
commercial world generating royalty income to help sustain research post
NSF support. This strategy has allowed the technology to grow apace with
the accelerating advances in network computing while allowing researchers
at Cornell to focus on the protocol, network infrastructure, and conference
management issues where its rich experience of the Internet environment
and wide userbase give a great advantage. The result today is a suite of
conferencing and collaboration tools well suited to breakout into software
modules for use in experiments with workstation telephony, distributed computing,
and emerging network standards.
Project
When NSF support began, CU-SeeMe was a rudimentary Mac-based application
that had been showcased in cooperation with the Global Schoolhouse project.
Unlike other videoconferencing tools of the day, CU-SeeMe required no special
equipment for video reception beyond a network connection and a gray-scale
monitor. Based on Cornell's belief that the value of a communications tool
is largely determined by the number of people who use it, this work aimed
to increase the accessibility of videoconferencing by focusing on low end,
widely available computing platforms and ultralowcost digital cameras. Later
in the grant period, as the software matured and the user interfaces for
the Mac and Windows versions approached parity, attention was focused on
cleanup and documentation of source code and protocols used by CU-SeeMe
desktop clients and reflectors. The bulk of this effort, representing nearly
5 years of software development work, was assembled and released via a web
site under terms of the CU-SeeMe Consortium Agreement. The goal was to produce
a meaningful summary and useful record of the project to date as well as
a set of robust and easily adaptable software tools for building new collaboration
technologies. It is our intent to keep this work available on the web as
a resource for future research. In addition:
A website was established early in the grant period (http://cu-seeme.cornell.edu)
to facilitate worldwide free distribution of the technology. This site has
proven to be extremely popular. Even today, when some aspects of CU-SeeMe
technology have been eclipsed by feature-rich (though often top-heavy) videoconferencing
products from commercial vendors, the daily download count hovers around
1,000 per day.
A high-traffic CU-SeeMe discussion list was formed. The Cornell strategy
was to network the skills of CU-SeeMe experimenters and enthusiasts worldwide
for maximum user feedback while also minimizing the software-support load
on the development group. This approach paid dividends in both directions.
Global technology partnerships: a consortium of universities, commercial
and non-profit companies and government agencies was formed to support continued
CU-SeeMe development. Information about the CU-SeeMe Consortium is available
at http://cu-seeme.cornell.edu/Consortium.html
UNIX-based reflector software was developed that serves to replicate and
re-distribute packet streams for multiparty conferences. Cornell's reflector
approach to multiparty conferencing is still unique in videoconference technology.
Over the grant period, enhanced conference controls such as password protection
were added along with bandwidth steering and hierarchical encoding features
to allow a graceful scaling of video information for lower bandwidth participants.
The reflector software also provides limited VAT, NV interoperability.
A Master Licensee agreement was arranged with White Pine Software for commercial
development. It was Cornell's strategy to leverage its programming efforts
with a commercial developer to provide additional features which are expensive
to develop, maintain, and support in a non-commercial context. This allowed
Cornell to focus on the protocol, network infrastructure, and conference
management issues where its rich experience of the Internet environment
and wide userbase give a great advantage.
Considerable work was done to guarantee reliable transport of auxiliary
data, including research into how bandwidth for such transport should be
shared with other conference data and how data distribution can be limited
to those who actually use it. Initial work was to define a plug-in architecture
to allow 3rd parties to write binary modules to extend the capabilities
of the program. Starting with a simple slide window and text messaging system,
the Cornell group migrated to built-in chat with extensive filtering features
and a full-featured slide window for capturing and sharing images. Today,
the slidewindow on the Mac platform offers built-in archiving with additional
image compression features.
Cornell completed its licensing structure for Cornell versions of the software.
To date, more than 70 internal-use licenses have been granted.
During its funding period, CU-SeeMe played a role in a number of interesting
events which exposed large numbers of people to the practical use of NSF
funding dollars. Among these were President Bill Clinton's speech at Dartmouth
College commencement, President Lee Teng-hui of Taiwan speech at Cornell,
and a live NASA feed of shuttle missions to schools and science centers.
Development work continued to keep the freely distributed Cornell software
fully compatible with the commercial product. We reorganized the program,
making it less fragmented and more maintainable, and tackled issues of conference
control, security, privacy, and appropriate use of public reflectors. Meanwhile,
issues of scaling over a wide range of connections were addressed, particularly
at the higher end of the spectrum. A cross-campus ATM network demonstration
was conducted using a special high speed version of CU-SeeMe. A second demonstration
used Cornell University Medical School's plug-in interface to share photographs
of clinical interest while allowing multiple conference participants to
annotate quality color images using white board and collaboration features.
A new UDP interface was written to take full advantage of Apple's Open Transport
networking architecture and a screen capture/slidewindow/chat filter package
was added to the Macintosh client. A 32-bit version of CU-SeeMe written
for Windows95/NT has proven extremely popular, accounting for more than
300,000 downloads since it's release in mid-1997.
Today, the various components of CU-SeeMe technology stand ready to be used
as modular units for future network research. Such projects might include
testing of protocols (Cells in Frames, ATM), the possible migration to a
transport protocol for real-time applications (RTP-V2), and the use of CU-SeeMe
in IP telephony. For instance, a recently developed telephone instrument
was used to operate CU-SeeMe as part of a campuswide workstation telephony
project. Other recent enhancements provide for larger screens, higher resolution
video, CD-quality audio, and desktop sharing features based on the greater
bandwidths available on the NGI and on the campuses of the consortium members.
Final versions of the Cornell software have been compiled, alpha tested,
and are ready for a summary release as MacOS and Win95/NT Versions 1.0.
A list of new features follows:
For Windows 95/NT:
For the Mac/OS:
Work at Rice University:
Under a subcontract to the project, Rice University installed a 50 user
commercial reflector, on a new 166 Mhz Compaq NT server. The server was
dedicated exclusively to the task of CU-SeeMe conferencing.
The reflector was fed by a client computer which was directly connected
to the Rice Vidnet switcher allowing a conference manager to send presentations
from any Vidnet event on campus out over CU-SeeMe. The Rice Vidnet connects
presentation venues (auditoriums, lecture halls, etc.) and classrooms to
an assortment of destinations. The NSF CU-SeeMe client computer is connected
directly to the Vidnet network hub in the computing center.
Two satellite dishes were installed on the roof of the Rice library, one
for occasional event downlinks and a second dish used for the SCOLA video
service. NSF money was used for the first dish. Though procurement and installation
of this dish cost substantially more than the budgeted amount, Rice University
paid the difference.
The satellite dishes are linked back to the Rice Vidnet switcher via dedicated
fiber optic links.
The CU-SeeMe client computer is in the same rack as the fiber-to-RF demodulator
for the campus cable TV feed. The campus cable system has 72 channels which
are provided by Phonoscope Cable. This close proximity to the cable head
end allows the use of a cable TV tuner to feed very high quality video into
the CU-SeeMe client when needed. For instance, NASA select is one of the
channels on the Phonoscope cable system.
A web site has been started which will have information about CU-SeeMe broadcasts
from Rice University. Take a look at http://www.rice.edu/rtv/. This site
will be the starting point for users which want to see events from Rice
utilizing CU-SeeMe.
The result is a new system which can be used by instructors, students, and
the public to attend events which would otherwise be unavailable.
Work at Texas A&M University:
The subcontract with TAMU/TEES had two main efforts: (1) Low complexity
speech coding under 16 kbits/s, and (2) Pyramidal video coding compatible
with the existing CU-SeeMe video coder. The speech coding effort centered
on a subband coding algorithm that operated at 10-13 kbits/s. This coder
used quadrature mirror filters to break the input band into nonuniform subbands,
thus allowing perceptually important bands to receive higher bit allocations
than other bands and to isolate the distortions produced to their particular
frequency band. This speech coder was tested and operated over a LAN connection
using a Sun Sparc10, but the complexity of the FIR filters used precluded
porting this coder to less than 100 MHz PCs. This coder should be implemented
with IIR subband filters and then it can be easily implemented on today's
PCs.
The pyramidal video coding work was very successful. A three level video
coder with resolutions of 60X80, 120X160, and 240X320, was developed that
was fully compatible with the standard 120X160 CU-SeeMe video stream, but
that only increased the transmitted rate by a factor of 2 to transmit the
higher resolution version. This coder was fully integrated in an Internet
conferencing tool called CafeMocha. This first video coder was gray scale
only, so subsequent work developed a 6 level video coder that had three
levels of black-and-white video and 3 levels of color video.
Conclusion:
CU-SeeMe employs a conference control protocol that has proven to be quite
robust and allows for the expression of detailed state regarding the relations
of each conference participant to each other participant. In conjunction
with the reflector software it allows for customized distribution of conference
media, so that nothing is transmitted unless it is used. The protocol is
limited in the size of the conference it can serve, but our investigations
have shown that this can be extended.
CU-SeeMe video is encoded in an ad hoc format that was designed for a particular
family of desktop machines that were widespread in mid 1992. What it lacks
in mathematical elegance, it makes up for in quickness. As computing power
increases, the CU-SeeMe software will eventually become obsolete. Nonetheless,
it played an essential role in bringing videoconferencing capabilities to
millions of users and making a suite of research tools which will continue
to play a role in network research for some time.
At a recent electronic town meeting broadcast over CU-SeeMe, NSF Director
Dr. Neal F. Lane listed five major goals of the institution:
1) Maintain effective leadership across basic science and engineering research.
2) Enhance connections between fundamental science and the national goals.
3) Stimulate partnerships that promote investments in science, engineering,
and technology for public use.
4) Prepare science professionals for the 21st century.
5) Raise the scientific and technical literacy of all Americans..
We are happy to conclude that the CU-SeeMe project touched somewhat on each
these goals.