Multimedia mail meeting notes
Meeting notes on connecting computers to send mixed-type messages in 1982.
Postel, J., "Multimedia mail meeting notes", RFC 807, DOI 10.17487/RFC0807, February 1982, <https://www.rfc-editor.org/info/rfc807>.
@misc{rfc807,
series = {Request for Comments},
number = 807,
howpublished = {RFC 807},
publisher = {RFC Editor},
doi = {10.17487/RFC0807},
url = {https://www.rfc-editor.org/info/rfc807},
author = {J. Postel},
title = {{Multimedia mail meeting notes}},
pagetotal = 6,
year = 1982,
month = feb,
} RFC text
Contents
Network Working Group J. Postel
Request for Comments: 807 ISI
9 February 1982
Multimedia Mail Meeting Notes
Introduction
A meeting was held at USC Information Sciences Institute on the 12th
of January 1982 to discuss multimedia mail issues and experiments.
The list of attendees is at the end of this memo.
Overview:
This meeting was called to discuss common interests in multi-media
computer mail experiments, and to agree on some specific initial
experiments.
Review of Status:
Review current status of multimedia efforts at CMU, ISI, MIT, COMSAT,
BBN, UCL, SRI.
CMU
Using PERQ, Quip for fax, LPCM vocoder from LL, will get NEC board
(3 chips) to replace vocoder. Will have a stand alone voice I/O
device that operates at 2400 baud (not packetized). Not working on
IP/TCP. Will use the IP and TCP from the BBN project. Already
using the BBN Jericho developed Pascal IP and CFTP. Interested in
word recognition of LPC digitized voice data. Planning to package
a synthesiser, an analyzer, and a pitch tracker on one board.
ISI
Using TOPS20 (code in BLISS10), and starting to use PERQ (code in
Pascal), RAPICOM 450 for fax. Main interest is in the data
structuring and message transport protocols.
MIT
Using Apollos, will program in MDL. Use of Apollos still limited
due to (1) MDL not completely implemented, (2) network interface
not yet available (waiting on multibus to then interface to
Ethernet). Will get NEC CCITT fax machine. Looking into VAX+BBN
BitGraph for future. Main work to date in design for sharing
message data in a conceptualy centralized filing system. Emphasis
on efficient storage and manipulation of multirecipient messages,
enclosures, citations, etc.
COMSAT
Using small 11s, Rapicom 450 and 500 fax machines, also have some
LPC vocoders. Substantial work has been done on encoding and
decoding both Rapicom 450 and CCITT T.4 fax data, and also on
manipulation of bitmap data (See RFC 803).
BBN
Using Jericho (code in Pascal). Will be building a prototype
system with the aim of investigating problems of data distribution
and privacy. Trying to produce portable software currently in
Pascal but may switch to ADA in the distant future. Have IP and
CFTP running, working on TCP. CFTP is a file transfer built
directly on IP.
UCL
Using LSI-11, Rapicom 450 fax machine, Grinell bitmap display.
May get PERQs (produced by ICL) in future. Have done quite a lot
of work on encoding/decoding for the Rapicom 450, and in bitmap
manipulations (e.g., cleanup of noise, scaling, cut and paste).
Interests in the relation of other types of display protocols to
multimedia effort e.g., VIDEOTEXT and TELETEXT.
SRI
There are three multimedia mail projects at SRI,sponsored by DCEC,
ARPA, and NAVELEX. SRI is a subcontractor (with Sytek and DTI) to
SDC in the DCEC program to produce protocol specifications for the
DoD. SRI has written service specifications for a mail system
similar to RFC759+767 with security features added. The ARPA
project is studying the issues involved in a multimedia mail
architecture based on RFC759+767, including negotiations,
envelopes, and multilevel security. The NAVELEX project is
investigating user interfaces for command and control
workstations, including natural language access to a data base.
The plan is to use RFC759+767 data structures to communicate text
and graphics, implemented on Foonly F-5s running Tenex with
Foo-Vision displays. The current choice for the graphics protocol
is Bisbey's GL2.
Discussion:
Coding/Decoding Algorithm:
We agree to use the encoding specified in the CCITT T.4
recommendation for the exchange of black and white bitmap data.
New Equipment:
It is reported that soon NEC will have CCITT T.4 Group 3 Fax
machines for about $15K.
NBS Mail Standard:
The possibility that the NBS Mail Format Standard is a workable
alternative to the RFC759+767 protocol is to be studied. What is
the relationship between these standards? Do we have comment on
the NBS Standard to submit to NBS?
Equipment Variations:
What happens if the receiver does not have equipment capable of
protraying some of the data (e.g., dosen't have a LPC vocoder)?
There are three subtopics: How many "standard" forms are
allowed?, What do you tell the user if you can't do it?, and How
does the cost of a medium (in memory or cpu cycles or portrayal
time) effect its use? The general feeling was that if there is
some type of data the receiving system can't portray, it should
simply tell the user "There is some data here I can't portray and
it's type is x.". The other aspects are items for further study.
Negotiation:
Does negotiation make sense in a mail system? What are the kinds
of things to be negotiated? One possiblity is to initially send
only pointers to the sections of a message, and have the recipient
system ask for the parts it can handle. Does this make sense in a
message relaying environment? Or for messsages with a fine scale
interleaving of media types? This topic is for further study.
Enclosures, Pointers, Cross References:
This seems too complex to handle at this meeting, so for now send
the whole thing. This is an item for further study.
Editing Multimedia Objects:
This is one of the most interesting parts of these research
projects, so each group will develop their own techniques, and we
will compare notes.
Manipulation of Bitmaps:
The issues involve aspect ratios, cut and paste, rotation and,
scaling. We need to compare notes and exchange algorithms. An
item for further study.
Mailbox IDs and Control Information:
With different types of source hosts and destination host
(timsharing systems, personal computers) and different types of
mail delivery schemes (append to file, query database server), do
we have sufficient control mechanisms and addressing modes? This
is an item for further study.
Storage and Transmission:
How do the requirements for memory, disk, cpu, and transmission
capacity differ for multimedia mail from text mail? This is an
item for further study.
Multimedia Virtual Message Format:
It is not clear that this is anything different than what is
specified by RFC759+767, but since it was not fully discussed it
is an item for further study.
Media Specific Protocols:
Specific format definitions are needed for each media. This is an
item for further study.
Interfaces to Other Systems:
How do we interface this multimeda system to opther systems (e.g.,
TELETEXT, VIDEOTEXT), and to text only mail systems (e.g.,
ARPAMAIL, TELEMAIL, ONTYM). This is an item for further study.
An Experiment:
BITMAP-TEXT DOCUMENT EXCHANGE
Move the data between computers as a file, using any file transfer
method available.
The File is a complete RFC 759 Document.
Bitmap data is in revised COMSAT Image Data Format.
Two compression types are to be used:
Raw Bitmap
CCITT Algorithm
Text data is in RFC767 Paragraph Format.
Action Items:
Start a New Note Series
For the exchange of protocols, formats, algorithms, procedures,
and other information between the multiamedia mail projects.
By: Jon Postel
Due: 1-Feb-82
Update RFCs 759 & 767
To remove typos and clairfy ambiguities.
By: Jon Postel
Due: 1-Feb-82
Update "Image Data Structure" Memo
To be more generally for bitmaps and not so focused on fax only.
By: Anil Agarwal
Due: 1-Feb-82
Compare and Contrast NBS Mail Standard with RFC 759+767 Protocol
Would the NBS Mail Standard be an adaquate alternative to the RFC
759+767 approach?
By: each site
Due: Unspecified
Issue the NBS Mail Standard as an RFC
To aid in wide consideration of it. (Where does the online file
come from?)
By: Jon Postel
Due: Unspecified
Report on the differences between the NBS Mail Standard and other
things.
What are the differences between the NBS standard and the
RFC759+767 protocol?, the IFIP plans?, the CCITT plans?, and the
ISO plans?
By: Debbie Deustch
Due: Unspecified
Demonstrate FAX-TEXT Document Exchange
This demonstration is to be ready before and repeated at the User
Interface Meeting at CMU.
By: all sites
Due: 19-20 April 82
Attendees:
Duane A. Adams DARPA/IPTO Adams@ISI (202) 694-8096
Vint Cerf DARPA/IPTO Cerf@ISI (202) 694-3049
Harry Forsdick BBN Forsdick@BBN (617) 497-3638
Bob Thomas BBN BThomas@BBND (617) 497-3483
Gene Ball CMU Ball@CMUA (412) 578-2569
Anil Agarwal COMSAT Agarwal@ISID (301) 863-6103
David L. Mills COMSAT Mills@ISID (202) 863-6092
Dave Lebling MIT PDL@MIT-XX (617) 253-1440
Jon Postel ISI Postel@ISIF (213) 822-1511
Greg Finn ISI Finn@ISIF (213) 822-1511
Alan Katz ISI Katz@ISIF (213) 822-1511
Carl Sunshine ISI Sunshine@ISIF (213) 822-1511
David Elliott SRI wde@SRI-KL (415) 859-4107
Andy Poggio SRI Poggio@SRI-Unix (415) 859 5094
Zaw-Sing Su SRI ZSu@SRI-Unix (415) 859-4576
Steve Kille UCL UCL-Netwiz@ISIE (uk) (01)387-7050
Peter Kirstein UCL PKirstein@ISIA (uk) (01)387-7050
Bill Tuck UCL UKSAT@ISIE (uk) (01)387-7050
AI ELI5
On this page
§1Early Multimedia Email Efforts
In January 1982, researchers from seven institutions gathered at USC Information Sciences Institute to discuss their work on multimedia email. Each organization—CMU, ISI, MIT, COMSAT, BBN, UCL, and SRI—had independently begun adding support for images, fax, and voice to their email systems.
At this time, email existed primarily for text. The challenge was that different organizations used different hardware (PERQ computers, Apollo workstations, Lisp Machines) and different encoding methods for images. Standardizing these efforts was essential for messages sent between organizations to work correctly.
Different colleges and companies had started trying to send pictures in email, but they were all doing it differently. The leaders met up to figure out how to make them all talk to each other.
§2What Each Site Was Building
CMU focused on voice—using an LPCM vocoder (a device that digitized speech) and an NEC board to replace it. MIT worked on storing shared message data in a centralized filing system and managing multi-recipient messages with enclosures. COMSAT had invested heavily in encoding and decoding both Rapicom fax data and bitmap (picture) data.
BBN was building a prototype system to investigate data distribution and privacy, with plans to support TCP. UCL had developed methods for encoding and decoding the Rapicom 450 fax machine and for bitmap manipulation like noise cleanup and image scaling. SRI ran three separate projects: one on mail protocols with security features, another on multimedia architecture including negotiations and multi-level security, and a third exploring natural language interfaces to data.
Some places were good at voice, some at pictures, and some at storing lots of messages. Each one was building their own thing, but they all needed the others to understand their formats.
§3Agreements and Standards
The group agreed to use the CCITT T.4 recommendation for black-and-white bitmap data exchange. This was an emerging international standard for compressing fax images. The decision meant each site could focus on supporting this single format rather than translating between proprietary compression methods.
A key unresolved question was negotiation: should senders initially send only pointers to message sections and let recipients request the parts they could handle? Or should entire messages always be sent? The group decided this needed further study, as it had different implications for message relaying and interleaved media.
Another major topic was handling equipment variations. What should happen if a receiving system could not portray some data—for instance, if it lacked a voice decoder? The consensus was that the system should simply notify the user: There is some data here I can't portray and its type is X.
They all agreed to use the same way of squeezing picture files small (called CCITT T.4). They also agreed that if a computer couldn't display something, it should just tell the person "I don't know how to show that."
§4Next Steps
The meeting produced several action items. Jon Postel would start a new note series for exchanging protocols, formats, algorithms, and procedures between the multimedia projects. Each site was to compare the emerging NBS Mail Standard with the RFC 759+767 approach (the existing ARPANET text mail protocol). The group scheduled a bitmap-text document exchange demonstration for April 1982 at a User Interface Meeting at CMU.
The framework agreed upon was simple: move bitmap data between computers as files using any available file transfer method, with the file structured as a complete RFC 759 document and bitmap data in the revised COMSAT Image Data Format, using either raw bitmap or CCITT Algorithm compression.
They agreed to share what they learned with each other through notes, and to show off a working example of sending both pictures and text together by April.