MPEG asks for MIME review for the MPEG21 file format

[Dave Singer]

At 14:08  +0100 15/05/07, Graham Klyne wrote:
>  > Correct, the main document inside the binary archive is indeed in XML.
>>  But the overall file format is binary.  Doesn't the mime type "+xml"
>>  suggest that the document is specialized XML only (i.e. a text document)?
>
>Not really - as I understand it, content transfer encoding tells us about the
>domain of the document.  The top-level media types make the 
>distinction between
>text and non-text (cf. RFC2046 - section 4.1.1 has specific relevant comment
>about restrictions on text/... types).   Thus, I'd say the use of
>application/... indicates otherwise.  As far as I'm aware, the MIME
>specifications don't actually discuss CRLF conversions beyond this, 
>though it's
>implicit that for text/... the line separators would be converted 
>from/to local
>form when encoding/decoding MIME objects.
>
>RFC 3023 (http://www.ietf.org/rfc/rfc3023.txt) describes the use of the +xml
>convention, and also defines application/xml, text/xml, etc.
>[[
>A.15 Why must I use the '+xml' suffix for my new XML-based media type?
>
>    You don't have to, but unless you have a good reason to explicitly
>    disallow generic XML processing, you should use the suffix so as not
>    to curtail the options of future users and developers.
>]]

OK.  I have no personal opinion on the matter (Christian might).

>  >> It would be very much easier to give useful review if there was at least a
>>>  publicly web-accessible summary of what this content type is expected
>>>  to convey.
>>
>>  Sure.  There are brief intros at
>>
>>  <http://www.chiariglione.org/mpeg/mpeg-tech.htm>;  have a look at
>>  ISO Base Media File Format
>>  and specifically:
>>  Digital Item File Format
>>
>>  The base file format specification contains a lot of otehr stuff as well
>>  (stuff MPEG-21 doesn't use), but if you want to view it, it is freely
>>  available
>>
>> 
>><http://isotc.iso.org/livelink/livelink/fetch/2000/2489/Ittf_Home/PubliclyAvailableStandards.htm>
>>  and find 14496-12
>
>Hmmm, with a quick scan, I can't really find any material about MPEG-21 there,
>which is what the registration is about.

The "Digital Item File Format" paper is precisely this format.  If 
you want to know precise bits, etc., it builds on the part 12 
specification (but only small pieces of it, and it's not specifically 
pulled out).

>
>Of course, this isn't technically required for the MIME type 
>registration, but I
>think it would help.  The wikipedia entries
>(http://en.wikipedia.org/wiki/MPEG-21,
>http://en.wikipedia.org/wiki/Digital_Item) are more helpful, though sketchy.

Sure.

>
>There's also:
>* http://www.chiariglione.org/mpeg/standards/mpeg-21/mpeg-21.htm
>* http://www.dlib.org/dlib/november03/bekaert/11bekaert.html
>
>I think that including a non-normative reference to something like these would
>make the registration vastly more useful.

OK.
-- 
David Singer
Apple Computer/QuickTime