Re: more profile confusion

On Wed, Jun 6, 2012 at 8:51 AM, Michael A Dolan <mdolan@newtbt.com> wrote:

> Another troubling profile sentence in 5.2 was called to my attention:****
>
> ** **
>
> If neitherttp:profile<http://www.w3.org/TR/ttaf1-dfxp/#parameter-attribute-profile>attribute
> norttp:profile<http://www.w3.org/TR/ttaf1-dfxp/#parameter-vocabulary-profile>element
> is present in a TTML document instance, and if the document interchange
> context does not specify a profile, then the DFXP Transformation profile
> applies.****
>
> ** **
>
> A “document interchange context” might well fully define a conforming
> subset definition, but it may or may not formally define a “profile” as
> defined in the recommendation.****
>
> ** **
>
> An instance document would more likely declare its conformance by some
> other means, such as reference to a schema, or using xml-model, or simply
> by its context (e.g. a branded MP4 file).****
>
> ** **
>
> When we get to overhauling the profile language, we should fix the above,
> minimally replacing “profile” with “conforming subset” or something more
> generic that does not imply a TTML Profile definition is required.
>

Actually, I think I do not agree with this. The point of the above cited
language is to ensure that the applicable profile is well defined, since it
is necessary to know the applicable profile in order to perform processing
in a compliant manner.

As reference to a profile defined/specified by a document interchange
context is intended to serve as a out-of-band protocol to allow
determination of which profile applies. It does not mean that a ttp profile
document must be available for either author or client, it means that the
information that would be included in such a document is known is some
manner, whether or not it is defined in a profile file.

Finally, the phrase "conforming subset" has no formal meaning/use in TTML
at present other than indirectly through the use of profile definitions.