- From: Cyril Concolato <cyril.concolato@enst.fr>
- Date: Wed, 26 Aug 2009 09:32:50 +0200
- To: Yves Lafon <ylafon@w3.org>
- CC: Media Fragment <public-media-fragment@w3.org>
Hi Yves, Yves Lafon a écrit : > On Thu, 16 Jul 2009, Cyril Concolato wrote: > > Dear Cyril, > >>>> mpeg-4 and mpeg-21 chose to take the route that the mime registration >>>> was merely a registration, a pointer from the code point (the mime >>>> type) to the spec. Is that a problem? >>> >>> Honestly, I'm not in the position to tell if this is a problem, however, >>> when I did my review [1] I implicitly was working under this assumption, >>> yes. >>> >>> Anyway, I think we are on the safe side, as the original question was >>> about >>> frag IDs in audio/*, image/*, and video/*' and we learned that MPEG21 >>> has >>> not registered anything there (but only in their own application/mp21). >> You have to make the distinction between the MPEG-21 Part 9 (File >> Format) and the MPEG-21 Part 17 (Fragment Identification of MPEG >> Resources). >> >> Part 9 defines a file format based on the ISO Base Media File Format. >> Its main purpose is to wrap media data with a XML description >> conformant to MPEG-21 Part 2 (Digital Item Declaration). Therefore it >> is registered as application/mp21. However due to the compatibility >> with the ISO BMFF, the same file, if it contains media data and >> conforms to other specifications, may be served as audio/mp4, >> video/mp4 ... I think looking at the MPEG-21 FF to find the answer to >> the question on your Wiki is not the right approach. > > Quick question there, is application/mp21 the XML description format? No, application/mp21 is the file format based on the ISO base file format. The XML description format in MPEG-21 called DID has, to my knowledge, no registered mime type. > And what is the relation with EXIF and XMP? I don't know how to answer this question. > Side question, what is the patent policy for MPEG21-Part17 and Part2 > (ie: are there different policies depending on the parts)? I don't think there are different policies for different parts. I think both follow the usual ISO rules. I don't see any patent statement in Part 17, which does not mean there aren't any patent, it just means people did not declare any. > >> On the other hands, Part 17 clearly indicates that it "specifies a >> normative syntax for URI Fragment Identifiers to be used for >> addressing parts of any resource whose Internet Media Type is one of: >> - audio/mpeg [RFC3003]; >> - video/mpeg [RFC2045, RFC2046]; >> - video/mp4 [RFC4337]; >> - audio/mp4 [RFC4337]; >> - application/mp4 [RFC4337]". >> >> Now, I don't know if the process was right, or if such fragment >> identifier scheme should appear in the registration forms of those >> media types but it seems to me that the important questions are more >> technical: is this scheme good or not, is it too complex to implement >> or not, should it be profiled or not, extended or not ... > > Looking at RFC3003, there is no link from it to MPEG21-Part17, so it > seems that you defined an inbound link from part7 to the data formats, > but not the other way round. Cheers, I think that's what MPEG did (not me). As I said, I don't know if the process was right. I just wanted to mention that fact. Cyril -- Cyril Concolato Maître de Conférences/Associate Professor Groupe Mutimedia/Multimedia Group Département Traitement du Signal et Images /Dept. Signal and Image Processing Ecole Nationale Supérieure des Télécommunications 46 rue Barrault 75 013 Paris, France http://tsi.enst.fr/~concolat
Received on Wednesday, 26 August 2009 07:33:15 UTC