- From: Evain, Jean-Pierre <evain@ebu.ch>
- Date: Thu, 10 Feb 2011 09:48:18 +0100
- To: 'Joakim Söderberg' <joakim.soderberg@ericsson.com>, "Bailer, Werner" <werner.bailer@joanneum.at>, David Singer <singer@apple.com>
- CC: "public-media-annotation@w3.org" <public-media-annotation@w3.org>
As you will see in my other response to David, if you do it for compression YOU MUST apply the same approach for all attributes using a pair URI/string. It is a matter of consistency. See my point about the RDF design, which I believe is not impacted by this. But what is the potential impact on the API?? Jean-Pierre -----Original Message----- From: public-media-annotation-request@w3.org [mailto:public-media-annotation-request@w3.org] On Behalf Of Joakim Söderberg Sent: jeudi, 10. février 2011 09:38 To: Bailer, Werner; David Singer Cc: public-media-annotation@w3.org Subject: RE: Moving the MA Ontology to 2nd LC, ma:compression, yet again Thank you David for the observation, and your proposal. Is should solve the previous problems. I suggest we accept it for a new publication. Regards /Joakim -----Original Message----- From: public-media-annotation-request@w3.org [mailto:public-media-annotation-request@w3.org] On Behalf Of Bailer, Werner Sent: den 10 februari 2011 09:24 To: David Singer Cc: public-media-annotation@w3.org Subject: RE: Moving the MA Ontology to 2nd LC, ma:compression, yet again Hi David, Thanks for your comment, I agree that the current definition text is inconsistent (and does not correctly reflect the consensus discussed in the call). Basically I agree to the definition you proposed, with the following comments: - Splitting into two attributes makes it clearer to know whether the value is a URI or free text, and is useful for applications that know which type of value they expect. Others need to check the content both values. - I'm not sure if we should include the suggestion to include the date in the URI: typically, these will already exist, and someone using this spec does not have control over them. - typo: " Either _one_ or both ..." Best regards, Werner > -----Original Message----- > From: public-media-annotation-request@w3.org [mailto:public-media- > annotation-request@w3.org] On Behalf Of David Singer > Sent: Donnerstag, 10. Februar 2011 01:09 > To: public-media-annotation@w3.org > Subject: Re: Moving the MA Ontology to 2nd LC, ma:compression, yet > again > > Hi guys > > I have reviewed the ma:compression documentation, and we're in a > strange state; what's there is the semantics I suggested using a > comma, not the revision following Jean-Pierre's suggestion using a "#"; > and the syntax doesn't match. We need to fix this before we send the > document for review. > > I just read through and found as many of the references for deriving > the compression value, from as many formats as I could. It wasn't > possible for all of them, alas. > > Here is another suggestion for this attribute; it preserves both the > possibility of a controlled vocabulary URI, and an uncontrolled > vocabulary string, but by keeping them distinct we allow them to have > precise syntax and semantics. I believe that this (a) supports all the > mappings -- at least the ones I can verify -- in the document and (b) > supports all the expressed needs and use cases I have heard of. We may > the value a tuple of the two parts, both optional. > > (Obviously we could fiddle with the formatting, documentation, names > used here, and so on.) > > * * * * * > > compression > > { (attName="identifier", attValue="URI" )?, (attName="indicator", > attValue="String")? } > > The compression type used. For container files (e.g., QuickTime, AVI), > the compression is not defined by the format, as a container file can > have several tracks that each use different encodings. In such a case, > several compression instances SHOULD be used. Thus, querying the > compression property of the track media fragments will return different > values for each track fragment. > > Either or both of two values may be supplied, an identifier and an > indicator. The indicator is a free-form string; this can be used when a > string is desired for user-display, or when the naming convention is > lost or unknown. > > The identifier is a URI that consists of a absolute-URU (RFC 3986, > section 4.3) and fragment (RFC 3986, section 3.5), that is, in the > form absolute-URI#name. The absolute-URI identifies the naming > convention used for the second parameter, which is a string name from > that convention. A URL is preferred for the URI, and if it is used, it > (a) should contain a date in the form mmyyyy, indicating that the owner > of the domain in the URL agreed to its use as a label around that date > and (b) should be de-referencable, yielding an informative resource > about the naming convention. > > Note that this use of URIs with fragments also closely matches RDF (see > <http://www.w3.org/TR/rdf-concepts/#section-fragID>). > > Note that for some container files, the format parameter can also carry > an extended MIME type to document this; see [RFC 4281] for one such > instance. > > * * * * > > Hypothetical examples: > > compression={"urn:example-org:codingnames2010#ITU-H264", "Advanced > Video Coding"} > compression={"http://example.net/012011/standards/codecs.htm#G711"} > compression={, "Raw audio"} > > where ITU-H264 and G711 are defined by example.org (who also defined a > URN to identify their naming conventions), and by example.net (who use > a URL to identify theirs). The second example gives only an identifier, > and the third example has no identifier, only an indicator. > > More concrete examples: > > compression={ , "/3" } > -- layer 3 compression in an ID3 block in an MP3 file > compression={"urn:x-ul:060E2B34.0401.0101.04020202.03020500", "MPEG > Layer II/III"} > -- layer 2 or 3 compression, SMPTE > > compression={ , "AVC MP@L42" } > -- AVC compression, Cablelabs > compression={ , "c125" } > -- AVC compression, IPTC > > compression={ , "34712" } > -- JPEG 2000, TIFF > > > David Singer > Multimedia and Software Standards, Apple Inc. >
Received on Thursday, 10 February 2011 08:49:02 UTC