Subject: [Slim] Requirements on a system for indication of preferences and capabilities of media, modalities and languages in real-time sessions

From: Gunnar Hellström <[email-masked]>
Date: Sat, 11 Jul 2015 10:53:12 +0200

I suggest that we insert a requirements chapter in the real-time 
humintlang draft.

Here is an initial proposal.
My intention is that these requirements summarize what would be needed 
to cover both the needs of traditional relay service users and users of 
different languages. If that is seen to cover too much, I can see a need 
to split the work in a language part and a relay service invocation part.

I also see a need to specify a BCP for the procedures for assisting 
(e.g. =relay) service invocation so that a hint to another party to 
invoke a specific assisting service has an opportunity to be done in an 
interoperable way.

But this is how I see the requirements for the humintlang specification. 
It would be good to get initial reactions until or in the meeting on 
Tuesday.

X. Requirements.
------------------------
The system for indication of preferences and capabilities shall meet the 
following requirements:

It shall enable negotiation of media, modalities and languages for a SIP 
session.

It shall be possible to use it during initiation and modification of a 
session.

The system shall consist of a set of indications and usage rules 
specified in this specification and other specifications.

The system shall enable a caller to indicate the media, modalities, 
languages and assisting services that the caller prefers to use during a 
real-time session that is about to be established or modified.

Entities involved in selecting callees and callees shall be enabled to 
view the caller preferences in order to select a callee of many, or 
adjust the set of media, modalities, languages and services provided in 
the session.

The caller shall be provided with indication of the resulting media, 
modalities, languages and services enabled during the session.

X.1 General
------------
It shall be possible to express capabilities and preferences with its 
transmission direction, for transmission or reception or bidirectional 
from the viewpoint of the entity sending the indication.

The indications shall be suitable for setting in personal profiles, in 
service profiles, or in terminal settings, and possible to adjust at 
session initiation time.

It shall be possible to present the outcome of exchange of the 
indications to users in the session.

X.2 Media indications.
-------------------------

It shall be possible to use the indications for audio, video and 
real-time text media.  ( and text messages????)

X.3 Modality indications.
----------------------------
It shall be possible to use indications for speech and hearing in audio 
media.

It shall be possible to use indications for transmitting text and 
receiving text in real-time text media.

( ???  It shall be possible to use indications for transmitting text 
messages and receiving text messages in text messaging media. ???)

It shall be possible to use indications for expressing sign language and 
perceiving sign language in video media.

It shall be possible to use indications for showing a speaker and for 
seeing a speaker in video media.

X.4 Service indications.
--------------------------
It shall be possible to use indications of type of and address of and 
state of invocation of an assisting service available for supporting the 
communication.

X.5 Language indications.
-----------------------------
It shall be possible to indicate ability to express language in a number 
of languages from the ones listed in the language tags of RFC 5646.

It shall be possible to indicate ability to perceive language in a 
number of languages from the ones listed in the language tags of RFC 5646.

The language indication shall be associated with a specific media, 
modality and direction.

It shall be possible to indicate ability to express language in an 
unspecified language, meaning a default for a region in the associated 
modality.

It shall be possible to indicate ability to perceive language in an 
unspecified language, meaning a default for a region in the associated 
modality.

It shall be possible to indicate use of media without any specific 
intention to use the medium for language communication.

X.6 Indication of level of preference or capability
--------------------------------------------------------
It shall be possible to indicate an absolute level of preference or 
capability to use a language, modality, media and direction combination 
with a coarse grading.
For preference, the grading shall at least be able to indicate strong 
preference vs can use vs possible fall back usage.
For capability, the grading shall at least be able to indicate good 
capability vs some capability vs limited capability.
Capability and preference shall use the same coding, the difference is 
only in the role of the entity providing the indication. Call parties 
express preferences, service providers express capabilities.

More than one direction/media/modality/language preference or capability 
can be expressed per level.

It shall be possible for a caller to express if the session should be 
set up or not if no matching direction/media/modality/language 
indications are found.

X.7 Type and quality indications
-------------------------------------
It shall be possible to indicate preference and capability of different 
types of real-time text production: conversational type versus 
captioning type. Conversational type is generated by the transmitting 
party in the session, or by a communications agent with moderate 
requirements on delay. Captioning type is generated as captions to 
another modality in the same session with low delay from the expression 
in the other modality. The original modality for captions can be speech 
or sign language.

It shall be possible to indicate with language indications if it is 
original or interpreted or artificially created contents.

In order to enable communication with persons who have speech that is 
weak or hard to understand, the following quality indications can be used:
     -It shall be possible to indicate that the quality of the expressed 
speech makes it hard to understand.
     -It shall be possible to indicate a capability to undertand speech 
that is weak or hard to understand.

In order to enable communication with persons who need cognitive support 
in the form of reminders or notetaking, the following quality 
indications can be used:
     -It shall be possible to indicate need of reminders or notetaking 
during a session.
     -It shall be possible to indicate a capability to provide reminders 
or take notes during a session.

X.8 Details of service indications
----------------------------------------
The user expressing the indications may be a frequent user of an 
assisting service, that supports the commuication in some often 
occurring need for modality or language translation. By indicating this 
service, a receiver of the indication can judge if invocation of that 
service will support matching of preferences and capabilities. Common 
assiting service types are relay service and language translation service.

The services are specified with service type, service address, 
invocation state and languages.
Possible service types are:
     Spoken language translation service translating between different 
spoken languages.
     Video relay service translating between sign language in video and 
speech in audio.
     Text relay service translating between text in real-time text and 
speech in audio.  ( even between text messages and audio exist )
     Captioned telephony adding real-time text in one direction to speech.
     Speech-to-speech adding clear speech when needed to speech that is 
weak or hard to understand
     Cognitive support adding reminders or memory notes to speech 
conversation ususlly in combination with the speech-to-speech service.

Service address shall be a URI where the service can be reached with one 
session for provision of the service within the media of that session.
(note that this is different from how most current relay services today 
work. They often have two call legs, one with an audio call and one with 
a multimedia call. )

Invocation state shall indicate if the service is already included in 
the call, and if so, the media/modality/language indications show the 
joint capabilities.
Invocation state can also contain a request to the other party to invoke 
the service if needed to complement the capabilities to achieve a 
functioning communication. This indication can be provided either by the 
offering or answering party.

Languages shall be media/modality/language indications in pairs showing 
the capabilities of the service.

X.9 Use in session establishment and modification
-------------------------------------------------------------
The indications shall be included in session offer / answer exchange.

Already specified ways to express media/modality/language shall be 
possible to use to the extent that they are usable.
That includes media and language tags on SIP level and media 
specifications and language tags on SDP level. For cases when these 
existing means imply limitations, these limitations shall be explained.

The method for identification of language preferences and capabilities 
in this specification is intended mainly for rapid ad-hoc session 
establishment and not intended to have the same ambitions as CLUE has 
for planned telepresence sessions.

The indications included in the offer shall represent the preferences 
and capabilities of the offering party.

The indications included in the answer shall represent the preferences 
and capabilities of the answering party actually planned to be used in 
the session.

X.10 Security
-----------
It shall be possible to hide the preference and capability indications 
from unintended inspection.

X.11 Not covered characteristics
------------------------------------
Many aspects of a conversation are not covered by the indications 
specified here.
Examples are:
     Gender
     Expertize area

/Gunnar

-- 
-----------------------------------------
Gunnar Hellström
Omnitor
[email-masked]
+46 708 204 288