RE: ISSUE: Changes to Simple Delivery Profile to Allow Use of Other Profiles from Michael A Dolan on 2012-09-19 (public-tt@w3.org from September 2012)

From: Michael A Dolan <mdolan@newtbt.com>
Date: Wed, 19 Sep 2012 09:01:05 -0700
To: <public-tt@w3.org>
Message-ID: <004301cd967f$fb69a470$f23ced50$@newtbt.com>
Sean-

 

Please read the email thread quoted below, where the discussion about 6.1.1
is clear and everyone seemed to concur last March.

 

But as I said,  I am OK with changing the purpose of profiles to be for the
use case that you (and Monica) want - I agree it seems more useful.  I just
oppose silently assuming a different purpose for profiles without first
changing the TTML spec to alter the meaning.

 

Regards,

 

                Mike

 

From: Sean Hayes [mailto:Sean.Hayes@microsoft.com] 
Sent: Wednesday, September 19, 2012 7:54 AM
To: Michael A Dolan; public-tt@w3.org
Subject: RE: ISSUE: Changes to Simple Delivery Profile to Allow Use of Other
Profiles

 

I don't recall that being the intent, and there is no language in the
specification I can see which makes such a restriction.

 

From: Michael A Dolan [mailto:mdolan@newtbt.com] 
Sent: 19 September 2012 07:22
To: public-tt@w3.org
Subject: RE: ISSUE: Changes to Simple Delivery Profile to Allow Use of Other
Profiles

 

I believe the intent of supporting more than one profile was only to allow
the specification of a single profile for each namespace used within the
document (e.g. ttml, smpte, etc), not for multiple profiles in the same
namespace as you describe as the desired use case (e.g. dfxp-full, sdp,
etc). See:

http://lists.w3.org/Archives/Public/public-tt/2012Mar/0015.html 

 

I believe the use case you wish to enable is neither intended, nor possible
given the current definition of how profiles are to be used.  But maybe I
misunderstand the use case you describe?

 

We should discuss this further in the meeting tomorrow.

 

                Mike

 

From: Monica Martin (MS OPEN TECH) [mailto:momartin@microsoft.com] 
Sent: Tuesday, September 18, 2012 4:51 PM
To: Michael A Dolan; public-tt@w3.org
Subject: RE: ISSUE: Changes to Simple Delivery Profile to Allow Use of Other
Profiles

 

A bit confusing Michael. None of the added text in Sections 1 or 5.4.2 is a
conformance requirement. The addition of ttp:profile element was to correct
an omission in Section 5.2.2.  Use of multiple ttp:profile is allowed by
TTML 1.0.[1]

 

I can see we could remove this text in Section 5.4.2 Note:  "See also
<http://dvcs.w3.org/hg/ttml/raw-file/tip/ttml10-sdp-us/Overview.html#conform
ance> Conformance."

 

Monica

 

[1] Section 5.2

The profile of TTML that must be supported by a TTML content processor in
order to process a document instance is specified either (1) by specifying
attp:profile attribute on the root tt element, as defined by
<http://www.w3.org/TR/2010/REC-ttaf1-dfxp-20101118/#parameter-attribute-prof
ile> 6.2.8 ttp:profile, or (2) by including one or more ttp:profile elements
in the head element, in accordance with
<http://www.w3.org/TR/2010/REC-ttaf1-dfxp-20101118/#parameter-vocabulary-pro
file> 6.1.1 ttp:profile.

 

From: Michael A Dolan [mailto:mdolan@newtbt.com] 
Sent: Tuesday, September 18, 2012 9:48 AM
To: public-tt@w3.org
Subject: RE: ISSUE: Changes to Simple Delivery Profile to Allow Use of Other
Profiles

 

I am concerned that this proposal perpetuates a misunderstanding about TTML
profiles.  Profiles are metadata signaling to the Presentation Processor
about what features are minimally required to properly render the document.
They are not, at least not directly, a signal for document conformance.

 

With the current definition in TTML, I'm not sure what value there is (and I
can see serious downsides) to signaling, for example, all of the following
profiles:

 

SDP-US

CFF-TT

DFXP-Full

 

The proper interpretation of the above, by virtue of the DFXP-Full, would be
that a Presentation Processor would need to support every single TTML
feature in order properly render such a document.

 

I'm pretty sure that's both not the intent of this proposal and obviously
harmful as an SDP-US Presentation Processor would be permitted to reject the
document.

 

If we want the profile to signal document conformance instead of required
presentation processor features, we need to make substantive changes to the
TTML 1.0 spec to change the definition of profile.

 

I'm OK with that change. But we can't implement this proposal without first
doing that.

 

Regards,

 

                Mike

 

From: Monica Martin (MS OPEN TECH) [mailto:momartin@microsoft.com] 
Sent: Tuesday, September 18, 2012 9:24 AM
To: 'public-tt@w3.org'; Michael A Dolan (mdolan@newtbt.com); Sean Hayes
Subject: ISSUE: Changes to Simple Delivery Profile to Allow Use of Other
Profiles

 

Issue: Allow more than one profile to be used in the SDP-US. Add use of
ttp:profile element.  

 

Benefit: Allows SDP-US to use
<http://www.w3.org/TR/2010/REC-ttaf1-dfxp-20101118/> TTML 1.0, SDP-US
profile URI, and other profiles.  TTML 1.0 already defines the mandatory
processing semantics for the intersection of required elements of the
profile(s) that apply (
<http://www.w3.org/TR/2010/REC-ttaf1-dfxp-20101118/#vocabulary-profiles>
Section 5.2).[1] 

 

Proposal to add the following:[2]

1. Language in Section 1 that indicates use of other profiles is not
precluded; retain URI requirement for this profile.

2. The profile element to the list of elements in R0007, Section 5.2.2.

3. Language in Section 5.4.2 that articulates how multiple profile elements
may exist.

 

We plan to enter into Issue/Tracker. The question was raised by DECE
community by Mike Dolan re: CFF-TT.

 

Thanks. Monica

 

Monica J Martin

Senior Program Manager

Microsoft Open Technologies, Inc. 

A subsidiary of Microsoft Corporation

 

 

[1] 

TTML 1.0 Section 5.2:  If more than one ttp:profile element appears in a
TTML document instance, then all specified profiles apply simultaneously."

 

[2] Proposed changes (in bold)

Section 1

This constrained profile enumerates a set of required TTML features, some of
which may be constrained in behavior, and the capabilities required of a
Presentation Processor
<http://www.w3.org/TR/ttaf1-dfxp/#conformance-presentation-processor>  in
TTML 1.0.  The semantics defined in TTML 1.0 apply unless otherwise
constrained in this profile.

 

Claims of conformance MUST use this URI and implement the required features
and constraints of use and processing outlined in this profile.  

 


Name

Designator


simple-delivery

http://www.w3.org/TR/profile/simple-delivery
<http://www.w3.org/TR/profile/online-delivery> 

 

Conformance to this profile does not preclude the:

.         Use of other features defined in TTML 1.0. Such behavior is not
defined here.  

.         Use of other profiles that may implement the features in this
profile. 

 

Section 5.4.2

Add to Note (1). NOTE: See also
<http://dvcs.w3.org/hg/ttml/raw-file/tip/ttml10-sdp-us/Overview.html#conform
ance> Conformance.  TTML 1.0 allows zero or more profiles (ttp:profile in
the head element) to be specified and used simultaneously. A player may
reject documents it does not understand.

 

Add to Note (2). NOTE: When the use attribute is used on the ttp:profile
element, the use attribute could indicate the geographical region for which
the profile is used. For example, specific styling capabilities could be
used in a particular geographical region. See also
<http://dvcs.w3.org/hg/ttml/raw-file/tip/ttml10-sdp-us/Overview.html#other_c
onstraints> Other Constraints.

 

Requirement R0007

Add ttp:profile element to the list.
Received on Wednesday, 19 September 2012 16:01:48 UTC