Dear Graham,
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. [Christian Timmerer (ITEC)] Yes there is a chance but it might be difficult since ISO is usually doing this only for technical reports, reference software, and in some exceptional cases for so-called "baseline" standards, i.e., those that are most relevant for a particular standard in order to become adopted by others (e.g., Part 2 of MPEG-21).
Furthermore, MPEG-21 Part 9 is based on the ISO base media file format which is a joint standard between MPEG and JPEG. The ISO base media file format is indeed publicly available [1-4]. However, we might get into troubles why we're asking ISO to make MPEG-21 Part 9 publicly available but not other MPEG file formats, etc. Dave might correct me if I say something wrong here. I think the best and easiest way how to proceed is to provide you (=IETF) the relevant (=MPEG-21) file format standard(s) through liaison at the next meeting which is at the beginning of July in Lausanne. Anyway, I'll also ask whether it is feasible to make Part 9 of MPEG-21 publicly available. Thanks. Best regards, -Christian [1] http://standards.iso.org/ittf/PubliclyAvailableStandards/c041828_ISO_IEC_144... [2] http://standards.iso.org/ittf/PubliclyAvailableStandards/c042292_ISO_IEC_144... [3] http://standards.iso.org/ittf/PubliclyAvailableStandards/c043226_ISO_IEC_144... [4] http://standards.iso.org/ittf/PubliclyAvailableStandards/c043689_ISO_IEC_144...
#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_IE C_TR_21000-1_2004(E).zip
[2]
http://standards.iso.org/ittf/PubliclyAvailableStandards/c041112_ISO_IE C_21000-2_2005(E).zip
-- Graham Klyne For email: http://www.ninebynine.org/#Contact