Structured format for transmission of multi-media documents
RFC 767
| Document | Type | RFC - Unknown (August 1980) | |
|---|---|---|---|
| Authors | |||
| Last updated | 2013-03-02 | ||
| RFC stream | Legacy stream | ||
| Formats | |||
| IESG | Responsible AD | (None) | |
| Send notices to | (None) |
RFC 767
<body> := <pd>
<pd> := <<sim>>
<<sim>> := name:"SIMULTANEOUS", <pe>
<pe> := name:"VOICE", <voice structure>
name:"GRAPHICS", <graphics structure>
or
proplist:(
name:"SIMULTANEOUS",
proplist:(
name:"VOICE", <voice structure>
name:"GRAPHICS", <graphics structure>
)endlist
)endlist
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A Structured Format for Transmission of Multi-Media Documents
Specification
Sequential Ordering
This option is used to indicate sequential time ordering. The
media in the sub-tree below this PD are not separate streams.
Using again the example above, assume GRAPHICS and VOICE data were
to be presented using sequential ordering.
<body> := <pd>
<pd> := <<seq>>
<<seq>> := name:"SEQUENTIAL", <pe>
<pe> := name:"VOICE", <voice structure>
name:"GRAPHICS", <graphics structure>
or
proplist:(
name:"SEQUENTIAL",
proplist:(
name:"VOICE", <voice structure>
name:"GRAPHICS", <graphics structure>
)endlist
)endlist
Independent Ordering
It is apparent that some output devices are very slow in
comparison to others. An example which demonstrates this is
facsimile. The majority of facsimile devices are slow. A
detailed picture transmitted at 9600 baud takes minutes to print.
It is inconvenient for the user to wait on such a device when the
voice or text information which accompanies it is short.
For example, if the document a facsimile image and the text
"Hello Frank, here's a copy of that picture you requested." The
user need not wait for the picture. The facsimile machine might
be spooled, in which case he would pick up the picture later. In
a sense the picture was time independent of the text.
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A Structured Format for Transmission of Multi-Media Documents
Specification
<body> := <pd>
<pd> := <<ind>>
<<ind>> := name:"INDEPENDENT", <pe>
<pe> := name:"FACSIMILE", <facsimile structure>
name:"TEXT", <text structure>
or
proplist:(
name:"INDEPENDENT",
proplist:(
name:"FACSIMILE", <facsimile structure>
name:"TEXT", <text structure>
)endlist
)endlist
A Stream Example
By making use of the structure and the sequential ordering option
it is possible to initiate a stream. The stream will proceed at
its own pace until concluded.
<body> := <pd>
<pd> := <<seq>>
<<seq>> := name:"SEQUENTIAL", <pe>
<pe> := <pd>
<pd> := <<sim>>
<<sim>> := name:"SIMULTANEOUS", <pe>
<pe> := name:"VOICE", <voice structure>
name:"GRAPHICS", <graphics structure>
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Specification
or
proplist:(
name:"SEQUENTIAL",
proplist:(
name:"SIMULTANEOUS",
proplist:(
name:"VOICE", <voice structure>
name:"GRAPHICS", <graphics structure>
)endlist,
name:"SIMULTANEOUS",
proplist:(
name:"VOICE", <voice structure>
name:"GRAPHICS", <graphics structure>
)endlist,
.
.
.
)endlist
)endlist
Such a document structure suggests a slide presentation.
Multiple Active Stream Example
This example is exotic but illustrates what is possible. By making
use of the structure and the simultaneous ordering it is possible
to start in parallel two or more separate streams. Each stream
will proceed at its own pace until all are concluded.
<body> := <pd>
<pd> := name:"SIMULTANEOUS", <pe>
<pe> = <pd>
<pd> := name:"SEQUENTIAL", <pe>
<pe> = <pd>
<pd> := name:"SIMULTANEOUS", <pe>
<pe> := name:"VOICE",
<voice structure>
name:"GRAPHICS",
<graphics structure>
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A Structured Format for Transmission of Multi-Media Documents
Specification
or
proplist:(
name:"SIMULTANEOUS",
proplist:(
name:"SEQUENTIAL",
proplist:(
name:"SIMULTANEOUS",
proplist:(
name:"VOICE", <voice structure>
name:"GRAPHICS", <graphics structure>
)endlist,
name:"SIMULTANEOUS",
proplist:(
name:"VOICE", <voice structure>
name:"GRAPHICS", <graphics structure>
)endlist,
.
.
.
)endlist
name:"SEQUENTIAL",
proplist:(
name:"SIMULTANEOUS",
proplist:(
name:"VOICE", <voice structure>
name:"GRAPHICS", <graphics structure>
)endlist,
.
.
.
)endlist
)endlist
)endlist
2.3.5. The Media
So far no explicit description has been given for the media classes
which fit into a PE. It is not known what types of media will be
supported in the various document stations in the future. Those for
which support is in part already available are:
TEXT
VOICE
FACSIMILE
GRAPHICS
Standard formats for data in each of these media must be defined.
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Specification
2.3.6. TEXT
The text data may be structured according to a variety of protocols
(yet to be defined). The top level of the data structure is a
property list which identifies the protocol, and the version of that
protocol.
name:"TEXT", proplist:(
name:"PROTOCOL", <protocol>,
name:"VERSION", <version>,
name:"DATA", <data>
)endlist
The first protocol is called PARAGRAPH, and the data is a list of
paragraphs, where each paragraph is a text element.
name:"DATA", list:(
text: <paragraph>
text: <paragraph>
.
.
.
)endlist
2.3.7. VOICE
Since a good deal of research has been done towards implementing the
transmission of voice data on the ARPANET, the Network Voice
Protocol (NVP) provides the basis for the standard for voice data
[24].
Voice data a property list which specifies the vocoder being used,
the transmission protocol and the parcel data. The parcel data form
is specific to the protocol used and is grouped in lists.
name:"VOICE", proplist:(
name:"VOCODER", <vocoder>,
name:"PROTOCOL", <protocol>,
name:"VERSION", <version>,
name:"DATA", <data>
)endlist
The NVP protocol has a number of parameters, the version number
specifies a certain set of the parameters used by the vocoder
hardware and software to set up timing and define the type of coding
used. It is not expected that within a document the version number
will change.
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A Structured Format for Transmission of Multi-Media Documents
Specification
NVP itself supports negotiation of these parameters to insure both
ends of a network speech connection 'understand' one another. Since
no such interactive negotiation is possible in a document system,
negotiation capabilities have been excluded. As differing hardware
becomes available new versions may be defined.
For the NVP protocol the data list will take the following form:
name:"DATA", list:(
bitstr: <parcel>
bitstr: <parcel>
.
.
.
)endlist
The items in the list are parcels. The individual parcels are bit
string data elements whose contents and length are predefined by the
version number. The number of parcels in a parcel group is
available from the item count in the enclosing list header.
2.3.8. FACSIMILE
There are a number of facsimile devices in use. While standards are
being established by CCITT [25], of the devices available today many
are incompatible due to proprietary compression algorithms. The
description of fax data will allow for the possibility of several
protocols.
name:"FACSIMILE", proplist:(
name:"DEVICE", <device>,
name:"PROTOCOL", <protocol>,
name:"DATA", <data>
)endlist
There are few facsimile devices interfaced to computers though, and
the existing experiments in the ARPANET all use the RAPICOM 450. A
first facsimile standard format will be based on the data structure
used for this machine [26]. That is, for device RAPICOM450 and
protocol BLOCK, the data will be:
name:"DATA", list:(
bitstr:<r450-block>,
bitstr:<r450-block>,
.
.
.
)endlist
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A Structured Format for Transmission of Multi-Media Documents
Specification
Where an r450-block is a 585 bit unit.
2.3.9. GRAPHICS
The situation for graphics bears much similarity to facsimile.
Devices on the market today have a variety of user interfaces and
options. A similar structure is defined.
name:"GRAPHICS", proplist:(
name:"DEVICE", <device>,
name:"PROTOCOL", <protocol>,
name:"DATA", <data>
)endlist
There are several candidate protocols for use in describing graphics
data in documents. One is the Network Graphics Protocol [27],
another is the Graphics Language [28,29], and a third is the
SIGGRAPH Core System [30].
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3. EXAMPLES & SCENARIOS
Example 1: Text Example
Suppose we want to send the following message:
Date: 1979-03-29-11:46-08:00
From: Jon Postel <Postel@ISIF>
Subject: Meeting Thursday
To: Danny Cohen <Cohen@ISIB>
CC: Linda
Danny:
Please mark your calendar for our meeting Thursday at 3 pm.
--jon.
It will be encoded in the structured format. The following will
present successive steps in the top down generation of this message.
The identification and command portions of the messages will not be
expanded here (see [1]).
1. message
2. (identification, command, document)
3. (ID:<<identification>>,
CMD:<<command>>,
DOC:( date, from, subject, to, cc, body))
4. (ID:<<identification>>,
CMD:<<command>>,
DOC:(DATE:date,
FROM:from
SUBJECT:subject,
TO:to,
CC:cc,
BODY:body))
5. (ID:<<identification>>,
CMD:<<command>>,
DOC:(DATE: 1979-03-29-11:46-08:00,
FROM: (NET:ARPANET,HOST:ISIF,USER:Postel,PERSON:Jon Postel),
SUBJECT: Meeting Thursday,
TO: (NET:ARPANET,HOST:ISIB,USER:Cohen,PERSON:Danny Cohen),
CC: (NET:ARPANET,HOST:ISIF,USER:Linda),
BODY:
Danny:
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Examples & Scenarios
Please mark your calendar for our meeting
Thursday at 3 pm.
--jon.))
6. PROPLIST:
(ID:<<identification>>,
CMD:<<command>>,
DOC:
PROPLIST:(
DATE: 1979-03-29-11:46-08:00,
FROM:
LIST:(
PROPLIST:(
NET:ARPANET,
HOST:ISIF,
USER:Postel,
PERSON:Jon Postel,
)ENDLIST,
)ENDLIST,
SUBJECT: Meeting Thursday,
TO:
LIST:(
PROPLIST:(
NET:ARPANET,
HOST:ISIB,
USER:Cohen,
PERSON:Danny Cohen,
)ENDLIST,
)ENDLIST,
CC:
LIST:(
PROPLIST:(
NET:ARPANET,
HOST:ISIF,
USER:Linda,
)ENDLIST,
)ENDLIST,
BODY:
Danny:
Please mark your calendar for our meeting
Thursday at 3 pm.
--jon.
)ENDLIST
)ENDLIST
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Examples & Scenarios
7. proplist:(
name:"ID", <<identification>>,
name:"CMD", <<command>>,
name:"DOC",
proplist:(
name:"DATE", name:"1979-03-29-11:46-08:00",
name:"FROM",
list:(
proplist:(
name:"NET", name:"ARPANET",
name:"HOST", name:"ISIF",
name:"USER", name:"Postel",
name:"PERSON", name:"Jon Postel",
)endlist,
)endlist,
name:"SUBJECT", text:"Meeting Thursday",
name:"TO",
list:(
proplist:(
name:"NET", name:"ARPANET",
name:"HOST", name:"ISIB",
name:"USER", name:"Cohen",
name:"PERSON", name:"Danny Cohen",
)endlist,
)endlist,
name:"CC",
list:(
proplist:(
name:"NET", name:"ARPANET",
name:"HOST", name:"ISIF",
name:"USER", name:"Linda",
)endlist,
)endlist,
name:"BODY",
text:"Danny:
Please mark your calendar for our
meeting Thursday at 3 pm.
--jon."
)endlist
)endlist
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Examples & Scenarios
Example 2: Multimedia Example
proplist:(
name:"ID", <<identification>>,
name:"CMD", <<command>>,
name:"DOC",
proplist:(
name:"DATE", name:"1980-08-06-11:46-08:00",
name:"FROM",
list:(
proplist:(
name:"NET", name:"ARPANET",
name:"HOST", name:"ISIF",
name:"USER", name:"Postel",
name:"PERSON", name:"Jon Postel",
)endlist,
)endlist,
name:"SUBJECT", text:"Multimedia Test Message",
name:"TO",
list:(
proplist:(
name:"GROUP", name:"Multimedia Experiment List",
)endlist,
)endlist,
name:"CC",
list:(
proplist:(
name:"NET", name:"ARPANET",
name:"HOST", name:"ISIF",
name:"USER", name:"Linda",
)endlist,
)endlist,
name:"BODY",
proplist:(
name:"SEQUENTIAL",
proplist:(
name:"TEXT",
proplist:(
name:"PROTOCOL", name:"PARAGRAPH",
name:"VERSION", index:"1",
name:"DATA",
list:(
text:"This is a test of multimedia mail."
text:"I hope you like it."
)endlist
)endlist
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A Structured Format for Transmission of Multi-Media Documents
Examples & Scenarios
name:"SIMULTANEOUS",
proplist:(
name:"VOICE",
proplist:(
name:"VOCODER", name:<vocoder>,
name:"PROTOCOL", name:"NVP",
name:"VERSION", index:"1",
name:"DATA",
list:(
bitstr:<parcel>
bitstr:<parcel>
)endlist
)endlist
name:"GRAPHICS",
proplist:(
name:"DEVICE", name:<device>,
name:"PROTOCOL", name:<protocol>,
name:"VERSION", index:<version>,
name:"DATA",<data>
)endlist
)endlist
)endlist
name:"SEQUENTIAL",
proplist:(
name:"TEXT,
proplist:(
name:"PROTOCOL", name:"PARAGRAPH",
name:"VERSION", index:"1",
name:"DATA",
list:(
text:"That was supposed to be some voice
and graphics in parallel."
text:"--jon."
)endlist
)endlist
)endlist
)endlist
)endlist
)endlist
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REFERENCES
[1] Postel, J., "Internet Message Protocol," RFC 759, 113,
USC/Information Sciences Institute, August 1980.
[2] Bhushan, A., K. Pogran, R. Tomlinson, and J. White, "Standardizing
Network Mail Headers," RFC 561, NIC 18516, September 1973.
[3] Myer, T., and D. Henderson, "Message Transmission Protocol,"
RFC 680, NIC 32116, 30 April 1975.
[4] Crocker, D., J. Vittal, K. Pogran, and D. Henderson, "Standard for
the Format of ARPA Network Text Messages," RFC 733, NIC 41952,
21 November 1977.
[5] Barber, D., and J. Laws, "A Basic Mail Scheme for EIN," INWG 192,
February 1979.
[6] Braaten, O., "Introduction to a Mail Protocol," Norwegian
Computing Center, INWG 180, August 1978.
[7] Crocker, D., E. Szurkowski, and D. Farber, "An Internetwork Memo
Distribution Capability - MMDF," Sixth Data Communications
Symposium, ACM/IEEE, November 1979.
[8] Haverty, J., D. Henderson, and D. Oestreicher, "Proposed
Specification of an Inter-site Message Protocol," 8 July 1975.
[9] Thomas, R., "Providing Mail Services for NSW Users," BBN NSW
Working Note 24, Bolt Beranek and Newman, October 1978.
[10] White, J., "A Proposed Mail Protocol," RFC 524, NIC 17140, SRI
International, 13 June 1973.
[11] White, J., "Description of a Multi-Host Journal," NIC 23144, SRI
International, 30 May 1974.
[12] White, J., "Journal Subscription Service," NIC 23143, SRI
International, 28 May 1974.
[13] Levin, R., and M. Schroeder, "Transport of Electronic Messages
Through a Network," Teleinformatics 79, Boutmy & Danthine (eds.)
North Holland Publishing Co., 1979.
[14] Earnest, L., and J. McCarthy, "DIALNET: A Computer Communications
Study," Computer Science Department, Stanford University, August
1978.
Postel [Page 31]
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References
[15] Crispin M., "DIALNET: A Telephone Network Data Communications
Protocol," DECUS Proceedings, Fall 1979.
[16] Caulkins, D., "The Personal Computer Network (PCNET) Project: A
Status Report," Dr. Dobbs Journal of Computer Calisthenics and
Orthodontia, v.5, n.6, June 1980.
[17] Postel, J., "NSW Transaction Protocol (NSWTP)," USC/Information
Sciences Institute, IEN 38, May 1978.
[18] Haverty, J., "MSDTP -- Message Services Data Transmission
Protocol," RFC 713, NIC 34739, April 1976.
[19] ISO-2014, "Writing of calendar dates in all-numeric form,"
Recommendation 2014, International Organization for
Standardization, 1975.
[20] ISO-3307, "Information Interchange -- Representations of time of
the day," Recommendation 3307, International Organization for
Standardization, 1975.
[21] ISO-4031, "Information Interchange -- Representation of local time
differentials," Recommendation 4031, International Organization
for Standardization, 1978.
[22] Postel, J., "DOD Standard Internet Protocol," USC/Information
Sciences Institute, IEN 128, NTIS number AD A079730, January 1980.
[23] CCITT-X.121, "International Numbering Plan for Public Data
Networks," Recommendation X.121, CCITT, Geneva, 1978.
[24] Cohen, D., "Specifications for the Network Voice Protocol (NVP),"
NIC 42444, RFC 741, NSC 68, RR-75-39, USC/Information Sciences
Institute, January 1976.
[25] CCITT-T.30, "Procedures for Document Facsimile Transmission in the
General Switched Telephone Network," Recommendation T.30, Orange
Book, V. 7, The International Telephone and Telegraph Consulative
Committee, International Telecommunication Union, Geneva, 1977.
[26] Treadwell, S., "FAX File Format," ARPANET Message, 14 November
1979.
[27] Sproull, R., and E. Thomas, "A Network Graphics Protocol,"
NIC 24308, Xerox Palo Alto Research Center, August 1974.
[Page 32] Postel
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A Structured Format for Transmission of Multi-Media Documents
References
[28] Bisbey, R., and D. Hollingworth, "A Distributable,
Display-Device-Independent Vector Graphics System for Command and
Control," RR-80-87, USC/Information Sciences Institute, July 1980.
[29] Bisbey, R., D. Hollingworth, and B. Britt, "Graphics Language,"
TM-80-18, USC/Information Sciences Institute, July 1980.
[30] Graphics Standard Planning Committee, "Core System," Computer
Graphics, V. 13, N. 3, SIGGRAPH, ACM, August 1979.
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[Page 34] Postel