[Restricting mailing list circulation to ietf-types for now] Christian, Thank you for the references - they are most helpful.
From part 1, and referring back to the proposed MIME type registration, posted at: http://www.alvestrand.no/pipermail/ietf-types/2007-May/001804.html it becomes clear that the content is NOT the DIDL which is what I had first thought.
Is there any chance that the standardization committee might be persuaded to make public release of part 9, describing this file format, in addition to parts 1, 2 and the schema already made public? I think that doing so would make the MPEG21 vision accessible to a wider base of developers. #g -- Christian Timmerer (ITEC) wrote:
Dear all,
as the “source” of this MIME type please apologize my late reply because I was one week w/o email access. It took some time to catch up. Regarding the “+xml” suffix I agree that it is inappropriate since an MPEG-21 file is not purely XML (see below for further details).
MPEG-21 Part 1 (Technical Report) is publicly available [1].
Concerning Digital Items, Digital Item Declaration, and MPEG-21 File Format, let me try to clarify something because I think there’s a misunderstanding:
· A Digital Item can be seen as a digital container format that puts (media) resources (e.g., audio, video, image, text (PDF), etc.) and metadata (e.g., data describing the resources, licenses, identifiers, etc.) within a standardized structure.
· A Digital Item is declared by an Digital Item Declaration (DID) which is based on the Digital Item Declaration Language (DIDL) that is a representation of the Digital Item Declaration Model. The model and DIDL are specified in MPEG-21 Part 2 which is publicly available [2]. The model is an abstract model defined using EBNF whereas DIDL – the representation of the model – is defined using XML Schema, thus, DID is XML-based. That is, it is possible that other, non-XML-based representation may be derived from the model (However, this should not be the discussion point)
· A Digital Item may be distributed which means that its declaration (i.e., DID) may be at one location whereas its (media) resources and metadata may be located elsewhere on various locations.
· The MPEG-21 file puts everything, i.e., (media) resources, metadata, and structure (i.e., declaration), into one file, the MPEG-21 file which is binary and contains the DID and (maybe) also the referenced/included (media) resources.
Hope this information is helpful for you.
Thank you.
Best regards,
-Christian
[1] http://standards.iso.org/ittf/PubliclyAvailableStandards/c040611_ISO_IEC_TR_...
[2] http://standards.iso.org/ittf/PubliclyAvailableStandards/c041112_ISO_IEC_210...
-- Graham Klyne For email: http://www.ninebynine.org/#Contact