Re: [Slim] IETF last call for draft-ietf-slim-negotiating-human-language (Section 5.4)

[Randall Gellens <[e-mail]>]

At 11:06 AM -0800 2/13/17, Bernard Aboba wrote:

>  Looking over Section 5.4, it seems to me that the title "Silly 
> States" may not be appropriate, because it mixes discussion of 
> combinations of media and language that have an "undefined" meaning 
> with combinations for which normative guidance can be provided  So 
> rather than having a single "Silly States" section, perhaps we can 
> have a section on "Undefined States" (for those combinations which 
> have an undefined meaning) provide normative guidance on defined 
> combinations elsewhere.
>
> 
> <https://tools.ietf.org/html/draft-ietf-slim-negotiating-human-language-06#section-5.4>5.4. 
> Silly States
>
>
>
>     It is possible to specify a "silly state" where the language
>     specified does not make sense for the media type, such as specifying
>     a signed language for an audio media stream.
>     An offer MUST NOT be created where the language does not make sense
>     for the media type.  If such an offer is received, the receiver MAY
>     reject the media, ignore the language specified, or attempt to
>     interpret the intent (e.g., if American Sign Language is specified
>     for an audio media stream, this might be interpreted as a desire to
>     use spoken English).
>
>     A spoken language tag for a video stream in conjunction with an audio
>     stream with the same language might indicate a request for
>     supplemental video to see the speaker.
>
>  [BA] Rather than using terms like "might" for combinations that could have a
>  defined meaning, I would like to see the specification provide normative
>  language on these use cases. In particular, I would like the 
> specification to describe:
>
>  a. What it means when a spoken language tag is included for a video stream.
>  Is this to be interpreted as a request for captioning?
>  b. What it means when a signed language tag is included for an audio stream.
>  Is the meaning of this "undefined" and if so, should it be ignored?
>  c. What it means when a signed language tag is included for a text stream.
>
>  If some of these scenarios are not defined, the specification can say
>  "this combination does not have a defined meaning" or something like that.

I will change the section title to "Undefined Combinations" and 
replace the text with:

    Specifying a non-signed language tag for a video media stream, or a
    signed language tag for a non-video media stream, is not defined.  An
    offer with such a combination SHOULD NOT be created.  If such an
    offer is received, the receiver MAY ignore the language specified.

I think this retains the intent of the old section while avoiding 
wading into the unclear issue of intent of such combinations.

-- 
Randall Gellens
Opinions are personal;    facts are suspect;    I speak for myself only
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I suppose when it gets to that point, we shan't know how it does it.
    --Alan Turing