Re: ISSUE-261: signaling docoument profile conformance is separate from decoder presentation requirements [TTML.next]

> > Some means must be defined to separately signal these different semantics.
> For example, we could create a new element and attribute - <ContentProfile> and contentProfile.

Sounds good. I also see value in exploring means for (a) defining a
content profile and (b) signaling conformance of a document to one or
more content profile.

> <ContentProfile>

What about following the <ttp:profile> template with the following tweaks:

- adding a @designator attribute allowing the content profile
designator to be specified
- @use can contain one or more URIs, each identifying a content
profile to be included in its entirety by reference, thereby avoiding
having to repeat all features already defined in another profile.
Perhaps @use can reference "profile" even when defining
"contentProfile" so that existing content designator can be used.
- allowing constraints over a base content profile to be specified
using value="prohibited"

<contentprofile designator="http://example.noname/profile1"
use="http://example.noname/profile4 http://example.noname/profile3"
xmlns="http://www.w3.org/ns/ttml#parameter">
     <features xml:base="http://www.w3.org/ns/ttml/feature/">
       <feature value="prohibited">#fontStyle-italic</feature>
       <feature value="use">#fontStyle-bold</feature>
     </features>
    <extensions xml:base="http://example.noname/profile1">
        <ttp:extension value="required">#prefilter-by-language</ttp:extension>
    </ttp:extensions>
</contentprofile>

> @contentProfile

What about a list of one or more content profile designator URIs, each
indicating conformance to a content profile, e.g.

<tt ttp:contentProfile="http://example.noname/profile1
http://example.noname/profile2">

Best,

-- Pierre

On Thu, Jul 11, 2013 at 9:16 AM, Timed Text Working Group Issue
Tracker <sysbot+tracker@w3.org> wrote:
> ISSUE-261: signaling docoument profile conformance is separate from decoder presentation requirements [TTML.next]
>
> http://www.w3.org/AudioVideo/TT/tracker/issues/261
>
> Raised by: Mike Dolan
> On product: TTML.next
>
> The profile element and attribute currently signal a feature set that a decoder must implement in order to reasonably present the document. Although it also hints at what features the document instance may include, it does not signal document instance conformance today.
>
> There is currently no mechanism to signal what profile a document instance conforms to (e.g. sdp-us).
>
> It is desirable to add this capability to TTML. However, simply adding this semantic to the existing profile element and attribute overly constrains the existing (decoder) and desired (document) semantics. It is unreasonable to require that the single element and attribute simultaneously signal both. For example, the fact that a document instance conforms to dfxp-full does and should not automatically infer that an sdp-us decoder could not properly present it. That is instance dependent. This situation is aggravated when multiple profiles are involved.
>
> Some means must be defined to separately signal these different semantics. For example, we could create a new element and attribute - <ContentProfile> and contentProfile.
>
>
>
>

Received on Friday, 12 July 2013 20:09:04 UTC