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https://github.com/ronf/nv

Network Video early videoconferencing tool
https://github.com/ronf/nv

multicast video-compression video-streaming

Last synced: 24 days ago
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Network Video early videoconferencing tool

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README 

        
Network Video tool

==================



This is an archive of the source code and binaries of one of the very

first videoconferencing tools available on the Internet. It was primarily

written by Ron Frederick, but also includes contributions from a number

of others to adapt it to support various video capture devices and

compression algorithms. See the individual source files for more detailed

author information.



Copyright and License

---------------------



The majority of this code is copyright Xerox Corporation and is released

until the following license:



    Copyright (c) Xerox Corporation 1992. All rights reserved.



    License is granted to copy, to use, and to make and to use derivative

    works for research and evaluation purposes, provided that Xerox is

    acknowledged in all documentation pertaining to any such copy or derivative

    work. Xerox grants no other licenses expressed or implied. The Xerox trade

    name should not be used in any advertising without its written permission.



    XEROX CORPORATION MAKES NO REPRESENTATIONS CONCERNING EITHER THE

    MERCHANTABILITY OF THIS SOFTWARE OR THE SUITABILITY OF THIS SOFTWARE

    FOR ANY PARTICULAR PURPOSE.  The software is provided "as is" without

    express or implied warranty of any kind.



    These notices must be retained in any copies of any part of this software.



Some individual source files are copyright Canon Information Systems, Digital

Equipment Corporation, Sun Microsystems, the Naval Research Laboratory, and

the University of Southern California. See the individual source files for

full copyright and license information.



Background (by Ron Frederick)

-----------------------------



In October of 1992, I began to experiment with the Sun VideoPix frame grabber

card, with the idea of writing a network videoconferencing tool based upon IP

multicast. It would be modeled after "vat" -- an audioconferencing tool

developed at LBL, in that it would use a similar lightweight session protocol

for users joining into conferences, where you simply sent data to a particular

multicast group and watched that group for any traffic from other group

members.



In order for the program to really be successful, it needed to compress the

video data before putting it out on the network. A goal I chose was to make

an acceptable looking stream of data that would fit in about 128kbps, or the

bandwidth available on a standard home ISDN line. I also hoped to produce

something that was still watchable that fit in half this bandwidth. This

meant I needed approximately a factor of 20 in compression for the particular

image size and frame rate I was working with. I was able to achieve this

compression and filed for a patent on the techniques I used, later granted

as patent `US5485212A`__: Software video compression for teleconferencing.



__ https://patents.google.com/patent/US5485212A



At the beginning of November, I released the videoconferencing tool "nv" (in

binary form) to the Internet community. After some initial testing, it was used

to videocast parts of the November Internet Engineering Task Force all around

the world. Approximately 200 subnets in 15 countries were capable of

receiving this broadcast, and approximately 50-100 people received video using

"nv" at some point in the week.



Over the next couple of months, three other workshops and some smaller

meetings have used "nv" to broadcast to the Internet at large, including the

Australian NetWorkshop, the MCNC Packet Audio and Video workshop, and the

MultiG workshop on distributed virtual realities in Sweden.



A source code release of "nv" followed in February of 1993, and in March I

released a new version of the tool where I introduced a new wavelet-based

compression scheme. In May of 1993, I added support for color video.



The network protocol used for "nv" and other Internet conferencing tools

became the basis of the Realtime Transport Protocol (RTP), standardized

through the Internet Engineering Task Force (IETF), first published in

RFCs `1889`__-`1890`__ and later revised in RFCs `3550`__-`3551`__, along

with various other RFCs that covered profiles for carrying specific

formats of audio and video.



__ https://tools.ietf.org/html/rfc1889

__ https://tools.ietf.org/html/rfc1890

__ https://tools.ietf.org/html/rfc3550

__ https://tools.ietf.org/html/rfc3551



Over the next couple of years, work contined on "nv", porting the tool

to a number of additional hardware platforms and video capture devices.

It continued to be used as one of the primary tools for broadcasting

conferences on the Internet at the time, including being selected by NASA

to broadcast live coverage of shuttle missions online.



In 1994, I added support in "nv" for supporting video compression algorithms 

developed by others, including some hardware compression schemes such as

the CellB format supported by the SunVideo video capture card. This also

allowed "nv" to send video in CUSeeMe format, to send video to users

running CUSeeMe on Macs and PCs.



The last publicly released version of "nv" was version 3.3beta, released

in July of 1994. I was working on a "4.0alpha" release that was intended

to migrate "nv" over to version 2 of the RTP protocol, but this work was

never completed. A copy of the 4.0 alpha code is included in this archive

for completeness, but it is unfinished and there are known issues with it,

particularly in the incomplete RTPv2 support.



The framework provided in "nv" later went on to become the basis of video

conferencing in the "Jupiter multi-media MOO" project at Xerox PARC, which

eventually became the basis for a spin-off company "PlaceWare", later

acquired by Microsoft. It was also used as the basis for a number of

hardware video conferencing projects that allowed sending of full NTSC

broadcast quality video over high-bandwidth Ethernet and ATM networks.

I also later used some of this code as the basis for "Mediastore", which

was a network-based video recording and playback service.