Re: Proposed Language for #111 - Revision 5

On Sat, Jan 9, 2016 at 10:19 AM, Andreas Tai <tai@irt.de> wrote:

> The proposal is a good way forward. I see two issues that have been raised
> in the last TTWG call by Mike Dolan and Piere Lemieux that still needs to
> be addressed.
>
> a) The processor that supports both IMSC profiles is still called
> "Multiple-Profile IMSC Processor". I think it may be better called
> "Combined IMSC Text and Image Profile Processor" or something similar.
>

The current term is already rather wordy, and this would make it more wordy
without altering its meaning. So I prefer leaving it as it stands.


>
> b) The section "normal processing" still mentions abortion of the
> processing  as first option and may be reworded as follows:
>
> "If a Document instance is considered compatible with a Combined IMSC Text
> and Image Profile Processor Processor, but is determined to be
> incompatible, then this processor may restart processing with the Image
> Profile as the default profile."
>

In the call, I asked if we could add this to the subsequent note on this
subject, which you can see below was modified to say this:

Note: If a Document Instance is considered compatible with a Processor, but
is determined to be incompatible, then normal processing may be aborted. As
an alternative, a Processor is permitted to restart processing with the
Image Profile as the default profile in case an incompatibility is detected
and the [profile defaulting] procedure was previously used to select the
Text Profile.



>
> Best regards,
>
> Andreas
>
> Am 08.01.2016 um 04:17 schrieb Glenn Adams:
>
> The following is revision 5 of my proposed text. I have added language to
> address the comments received today from Mike and Nigel. Revisions (from
> what we reviewed in today's meeting) are highlighted.
>
> Add to Section 3:
> IMSC Processor. A *Processor* that supports one or both IMSC Profiles.
> Single-Profile IMSC Processor. An IMSC Processor that supports one and
> only one of the profiles defined in Section 5, namely, the Text Profile or
> the Image Profile. Multiple-Profile IMSC Processor. An IMSC Processor that
> supports both of and only the profiles defined in Section 5, namely, both
> the Text Profile and the Image Profile.
> Compatible Profile. A non-IMSC profile with which IMSC is expressly
> designed to be compatible for the purpose of enhancing content
> interoperability. A Document Instance declared or determined to be
> associated with a Compatible Profile does not violate IMSC defined content
> constraints with respect to one of the profiles defined in Section 5.
> Note: The profiles defined by [EBU-TT-D], [ST2052-1], and [ttml10-sdp-us]
> are examples of Compatible Profiles.
> Create a new Section 5.4, entitled *Profile Specification and Processing*:
> [profile specification]
> The ttp:profile attribute SHOULD be present on the tt element and equal
> to the designator of the IMSC1 profile to which the document conforms;
> unless the document also conforms to [EBU-TT-D], in which case the
> ttp:profile attribute SHOULD NOT be present on the tt element, and
> instead the designat or of the IMSC1 profile to which the document conforms
> and the URI "urn:eebu:tt:distribution:2014-01" SHOULD each be carried in
> an ebuttm:conformsToStandard element as specified in [EBU-TT-D].
> [profile defaulting]
> A Single-Profile IMSC Processor SHALL process a Document Instance in
> accordance to the single profile which it supports. If a profile is
> determined by [profile specification] and its value is not equal to the
> profile designator associated with that single supported profile and is
> not a Compatible Profile with respect to that single supported profile,
> then the Document Instance MAY be considered incompatible with that
> Processor and subject to abort processing. If no profile is determined by [profile
> specification], then the Document Instance SHOULD be tentatively
> considered to be compatible with that Processor and subject to normal
> processing.
> A Multiple-Profile IMSC Processor SHALL process a Document Instance in
> accordance to one of its supported profiles. If a profile is determined
> by [profile specification] and its value is not equal to the profile
> designator associated with any of the supported profiles and is not a
> Compatible Profile with respect to any of the supported profiles, then
> the Document Instance MAY be considered incompatible with that Processor
> and subject to abort processing. If no profile is determined by [profile
> specification], and if no external profile metadata is provided by the
> Document Interchange Context, then the Document Instance SHOULD be
> tentatively considered to be compatible with the Text Profile and subject
> to normal processing as such.
> In order to avoid the invocation of this [profile defaulting] procedure,
> content authors and interchange agents SHOULD specify the profile that
> applies to a Document Instance, by means of either the [profile
> specification] procedure or external profile metadata, or both. If both
> internal and external profile metadata is provided and if there is a
> disagreement between the two designated profiles, then the external profile
> metadata takes priority.
> Note: A Document Interchange Context can obtain external profile metadata
> by multiple means, including but not limited to: profile parameter data
> provided by a content container or envelope, using a pre-processor that
> attempts to guess the applicable profile, etc.
> Note: If a Document Instance is considered compatible with a Processor,
> but is determined to be incompatible, then normal processing may be
> aborted. As an alternative, a Processor is permitted to restart
> processing with the Image Profile as the default profile in case an
> incompatibility is detected and the [profile defaulting] procedure was
> previously used to select the Text Profile.
> Note: The determination and processing of the profile of an arbitrary TTML
> Document Instance that is not compatible with either Profile defined herein
> is outside the scope of this specification.
> Modify Section 6.10 #profile entry to replace the first paragraph
> "The ttp:profile attribute ..."
> with the following:
> "The constraints and recommendations specified by [profile specification]
> (see §5.4 above) apply."
>
>
>