Registration for application/ttml+xml
Philippe Le Hegaret <plh <at> w3.org>
2012-09-06 14:19:29 GMT
Hello,
This is Appendix C of TTML 1.0.
http://www.w3.org/TR/ttaf1-dfxp/#media-type-registration
Comments on this registration would be greatly appreciated.
Type name:
application
Subtype name:
ttml+xml
Required parameters:
None.
Optional parameters:
charset
Same as application/xml media type, as specified in [XML Media
Types] or its successors.
profile
The document profile of a TTML document may be specified using
an optional profile parameter, which, if specified, the value of
which must adhere to the syntax and semantics of ttp:profile
parameter defined by Section 6.2.8 ttp:profile of the published
specification.
Encoding considerations:
Same for application/xml. See [XML Media], Section 3.2.
Security considerations:
As with other XML types and as noted in [XML Media] Section 10,
repeated expansion of maliciously constructed XML entities can
be used to consume large amounts of memory, which may cause XML
processors in constrained environments to fail.
In addition, because of the extensibility features for TTML and
of XML in general, it is possible that "application/ttml+xml"
may describe content that has security implications beyond those
described here. However, if the processor follows only the
normative semantics of the published specification, this content
will be outside TTML namespaces and may be ignored. Only in the
case where the processor recognizes and processes the additional
content, or where further processing of that content is
dispatched to other processors, would security issues
potentially arise. And in that case, they would fall outside the
domain of this registration document.
Interoperability considerations:
The published specification describes processing semantics that
dictate behavior that must be followed when dealing with, among
other things, unrecognized elements and attributes, both in TTML
namespaces and in other namespaces.
Because TTML is extensible, conformant "application/ttml+xml"
processors must expect that content received is well-formed XML,
but it cannot be guaranteed that the content is valid to a
particular DTD or Schema or that the processor will recognize
all of the elements and attributes in the document.
Published specification:
Timed Text Markup Language (TTML) 1.0.
Applications that use this media type:
TTML is used in the television industry for the purpose of
authoring, transcoding and exchanging timed text information and
for delivering captions for television material repurposed for
the internet.
There is partial and full support of TTML in components used by
several Web browsers plugins, and in a number of caption
authoring tools.
Additional information:
Magic number(s):
File extension(s):
.ttml
Macintosh file type code(s):
"TTML"
Fragment identifiers:
For documents labeled as application/ttml+xml, the fragment
identifier notation is intended to be used with xml:id
attributes, as described in section 7.2.1 of the Timed Text
Markup Language (TTML) 1.0 specification.
Person & email address to contact for further information:
Timed Text Working Group (public-tt <at> w3.org)
Intended usage:
COMMON
Restrictions on usage:
None
Author:
The published specification is a work product of the World Wide
Web Consortium's Timed Text (TT) Working Group.
Change controller:
The W3C has change control over this specification.
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