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<title>Re: MPEG asks for MIME review for the MPEG21 file format</title>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Dear all,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'> 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).<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>MPEG-21 Part 1 (Technical Report) is publicly available [1].<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Concerning Digital Items, Digital Item Declaration, and MPEG-21
File Format, let me try to clarify something because I think there’s a
misunderstanding:<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span
style='font-size:11.0pt;font-family:Symbol;color:#1F497D'><span
style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>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.<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span
style='font-size:11.0pt;font-family:Symbol;color:#1F497D'><span
style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>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)<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span
style='font-size:11.0pt;font-family:Symbol;color:#1F497D'><span
style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>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.<o:p></o:p></span></p>
<p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span
style='font-size:11.0pt;font-family:Symbol;color:#1F497D'><span
style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>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.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Hope this information is helpful for you. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thank you.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Best regards,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'> -Christian<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>[1] <a
href="http://standards.iso.org/ittf/PubliclyAvailableStandards/c040611_ISO_IEC_TR_21000-1_2004(E).zip">http://standards.iso.org/ittf/PubliclyAvailableStandards/c040611_ISO_IEC_TR_21000-1_2004(E).zip</a><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>[2] <a
href="http://standards.iso.org/ittf/PubliclyAvailableStandards/c041112_ISO_IEC_21000-2_2005(E).zip">http://standards.iso.org/ittf/PubliclyAvailableStandards/c041112_ISO_IEC_21000-2_2005(E).zip</a><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div>
<p class=MsoNormal><span style='font-size:8.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>:--<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:8.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>:- <b>Dipl.-Ing. Dr. Christian Timmerer</b><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:8.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>:- Department of Information Technology (ITEC)<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:8.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>:- Klagenfurt University, Austria<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:8.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>:- http://research.timmerer.com<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:8.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>:----------------------------------------------------------<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:8.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:8.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>>> Visit the IT Campus Carinthia<o:p></o:p></span></p>
<p class=MsoNormal><span lang=DE style='font-size:8.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>>> http://www.it-campus.at<o:p></o:p></span></p>
</div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'>
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<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Dave Singer
[mailto:singer@apple.com] <br>
<b>Sent:</b> Monday, May 14, 2007 8:32 PM<br>
<b>To:</b> Graham Klyne; Stephan Wenger; Christian Timmerer (ITEC)<br>
<b>Cc:</b> ietf-liaisons@ietf.org; ietf-types@alvestrand.no<br>
<b>Subject:</b> Re: MPEG asks for MIME review for the MPEG21 file format<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<div>
<p class=MsoNormal>I've added Christian here, who actually authored the
document.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>At 8:50 +0100 14/05/07, Graham Klyne wrote:<o:p></o:p></p>
</div>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'>
<p class=MsoNormal>I have a couple of comments:<br>
<br>
(1) the "Encoding considerations" section appears to confuse MIME
requirements<br>
for text with encoding for transmission over non-binary channels. A MIME<br>
content transfer encoding of "Binary" would be sufficient to indicate<br>
prohibition of CR/LF conversion or 7-bit stripping.<o:p></o:p></p>
</blockquote>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>I think this text was copied from other MIME registrations.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'>
<p class=MsoNormal><br>
(2) the subtype name -- if I recall correctly, MPEG-21 uses an XML
encapsulation<br>
layer (MPEG21-DIDL) for assembling various subparts into a composite for<br>
transmission (unfortunately, lack of a freely available online version of the<br>
cited document means that I can't check this). If I am correct here, then
it<o:p></o:p></p>
</blockquote>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'>
<p class=MsoNormal>may be more appropriate to use content type name
"application/mp21+xml".<o:p></o:p></p>
</blockquote>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>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)?<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'>
<p class=MsoNormal><br>
Also, if I recall correctly, the use of BASE64 for binary components within an<br>
MPEG21-DIDL XML wrapper is covered by the MPEG21 specification itself, so it
may<br>
be quite inappropriate to suggest Base64 encoding applied at the MIME level.<o:p></o:p></p>
</blockquote>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>The file format contains the XML, and also the attached
binary resources, outside the XML but inside the file format. They are
not (necessarily or normally) encoded at all.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'>
<p class=MsoNormal><br>
It would be very much easier to give useful review if there was at least a<br>
publicly web-accessible summary of what this content type is expected to
convey.<o:p></o:p></p>
</blockquote>
<div>
<p class=MsoNormal><br>
Sure. There are brief intros at<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><http://www.chiariglione.org/mpeg/mpeg-tech.htm>;
have a look at<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:18.0pt;font-family:"Verdana","sans-serif";
color:#0E0180'>ISO Base Media File Format</span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>and specifically:<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:18.0pt;font-family:"Verdana","sans-serif";
color:#0E0180'>Digital Item File Format</span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>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<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><http://isotc.iso.org/livelink/livelink/fetch/2000/2489/Ittf_Home/PubliclyAvailableStandards.htm><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>and find 14496-12<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>Christian may well have introductory material as well.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal>Hope that helps.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal style='margin-bottom:12.0pt'><o:p> </o:p></p>
</div>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'>
<p class=MsoNormal><br>
#g<br>
--<br>
<br>
<br>
Stephan Wenger wrote:<br>
> That's Dave Singer as the contact, of course. Sorry for the typo.<br>
> Stephan<br>
><br>
> On May 14, 2007, at 6:33 AM, Stephan Wenger wrote:<br>
><br>
>> Folks,<br>
>> MPEG (ISO/IEC JTC1 SC29) sent us an liaison statement asking us to<br>
>> review their draft for a MIME registration of the MPEG-21 file<br>
>> format. I know nothing about the subject matter, but hope some
of you<br>
>> could give them a hand. Please direct any technical questions to
Save<br>
>> Singer of Apple, singer@apple.com
<mailto:singer@apple.com>. Below,<br>
>> please find what I believe they want to register. Their full
liaison<br>
>> statement (in a bunch of word files) can be found<br>
>> here: https://datatracker.ietf.org/public/liaisons.cgi, look for<br>
>> ISO/IEC JTC1 SC29, May 2007<br>
>> Best regards,<br>
>> Stephan<br>
>><br>
>>> MIME media type name: application<br>
>>> MIME subtype name: mp21<br>
>>> Required parameters: none<br>
>>> Optional parameters: none<br>
>>> Encoding considerations: base64 IS generally preferred; files are<br>
>>> binary and should be transmitted without CR/LF conversion, 7-bit<br>
>>> stripping, etc.<br>
>>> Security considerations: It is possible to inject non-compliant
MPEG<br>
>>> streams (Audio, Video, and Systems) in the MP21 file to overload
the<br>
>>> receiver/decoder's buffers. This might compromise the
functionality<br>
>>> of the receiver or even crash it.<br>
>>> An MP21 file supports the storage of stream types, including commands<br>
>>> that are executed on the terminal such as Digital Item Methods
based<br>
>>> on ECMASCRIPT for which also bindings to Java(TM) and C++ exists.
It<br>
>>> is possible to use one or more of the above in a manner
non-compliant<o:p></o:p></p>
</blockquote>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'>
<p class=MsoNormal>>>> to MPEG to crash the receiver or temporarily
make it unavailable.<br>
>>> Authentication mechanisms can be used to validate of the sender
and<br>
>>> the data to prevent security problems due to non-compliant
malignant<br>
>>> MP21 files.<br>
>>> Interoperability considerations: A number of interoperating<br>
>>> implementations exist within the ISO/IEC 21000 community, and that<br>
>>> community has reference software for reading and writing the file
format.<br>
>>> Published specification: ISO/IEC 21000-9:2005<br>
>>> Applications which use this media type: Multimedia<br>
>>> Additional information:<br>
>>><br>
>>> Magic number(s): none<br>
>>><br>
>>> File extension(s): mp21 and mpg21 are both declared at<br>
>>> http://pitch.nist.gov/nics/ and http://filext.com/<br>
>>><br>
>>> Macintosh File Type Code(s): mp21 is registered with Apple.<br>
>>><br>
>>> Person & email address to contact for further information:
David<br>
>>> Singer, singer@apple.com <mailto:singer@apple.com><br>
>>> Intended usage: COMMON<br>
>>> Author/Change controller: David Singer, ISO/IEC 21000 file format
chair<br>
><br>
<br>
--<br>
Graham Klyne<br>
For email:<br>
http://www.ninebynine.org/#Contact<o:p></o:p></p>
</blockquote>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<pre>-- <o:p></o:p></pre>
<div>
<p class=MsoNormal>David Singer<br>
Apple Computer/QuickTime<o:p></o:p></p>
</div>
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