Writing XMP Metadata - Using Single or Multiple rdf:Description blocks

Writing XMP Metadata - Using Single or Multiple rdf:Description blocks

I am attempting to modify the code from PHP_JPEG_Metadata_Toolkit_1.12 so
that it will read and write XMP data correctly for jpeg files. Currently,
the jpeg files (when saved by the Toolkit) give errors with Adobe
Photoshop & Bridge
There are two ways I'm seeing the XMP RDF schema used by Photoshop. The
first is what Photoshop is actually saving in the jpg and which I am
importing. Photoshop uses a single rdf:Description block for everything.
It throws many schema identifiers (urls) within the block itself PLUS adds
values for many metadata fields. Then following are tag blocks for Dublin
Core, Photoshop, Iptc4xmpCore, etc., but all lumped together within a
single Description tag.
The second is the neatly formatted Metadata displayed inside of Photoshop
"File Info" that follows the XMP documentation for RDF (which states "By
convention, all properties from a given schema, and only that schema, are
listed within a single rdf:Description element.")
I've been able to fix the problem with Photoshop giving errors when edited
by the Toolkit by following the example of what Photoshop actually sends
(everything under one rdf:Description)
Two questions: Any idea why Photoshop saving the XMP metadata different
from what it shows inside the program? And … Why should I spend the time
to format my output to the RDF specs when it works nicely all jumbled
together in a single rdf:Description? I am new to working with all this
and so any guidance would be appreciated.
These examples are edited so you can more easily see the formatting
differences only - please forgive content discrepancies between the two
that are just from editing.
Here is what I am actually receiving from Photoshop (edited):
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<rdf:Description rdf:about=""
xmlns:xmpMM="http://ns.adobe.com/xap/1.0/mm/"
xmlns:stRef="http://ns.adobe.com/xap/1.0/sType/ResourceRef#"
xmlns:stEvt="http://ns.adobe.com/xap/1.0/sType/ResourceEvent#"
xmlns:xmp="http://ns.adobe.com/xap/1.0/"
xmlns:xmpRights="http://ns.adobe.com/xap/1.0/rights/"
xmlns:Iptc4xmpCore="http://iptc.org/std/Iptc4xmpCore/1.0/xmlns/"
xmlns:photoshop="http://ns.adobe.com/photoshop/1.0/"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmpMM:DocumentID="xmp.did:8808E8B6139411E3A70AB29CEEC8FF6C"
xmpMM:InstanceID="xmp.iid:0071BBEF4517E311BCBCC2DF868D188C"
xmpMM:OriginalDocumentID=""
xmp:CreatorTool="(PHP JPEG Metadata Toolkit v1.12)"
xmp:MetadataDate="2013-09-06T15:44:49-07:00"
xmp:ModifyDate="2013-09-06T15:44:49-07:00"
xmp:CreateDate="2013-09-06T15:22:46-07:00"
xmpRights:Marked="True"
xmpRights:WebStatement="MY WEB ADDRESS"
Iptc4xmpCore:IntellectualGenre=""
photoshop:Instructions="OOOInstructions"
photoshop:Headline="OOOHeadline"
photoshop:CaptionWriter="MY NAME"
dc:format="image/jpeg">
<xmpMM:DerivedFrom
stRef:instanceID="6B5F4850BB0819F254E40401F67ACAC9"
<stRef:documentID="6B5F4850BB0819F254E40401F67ACAC9"/>
<xmpRights:UsageTerms>
<rdf:Alt>
<rdf:li xml:lang="x-default">MY INFO HERE</rdf:li>
</rdf:Alt>
</xmpRights:UsageTerms>
<dc:description>
<rdf:Alt>
<rdf:li xml:lang="x-default">OOODescription
</rdf:li>
</rdf:Alt>
</dc:description>
</rdf:Description>
</rdf:RDF>
Here is Photoshops nicely formatted view (edited)
<rdf:Description rdf:about=""
xmlns:xmpMM="http://ns.adobe.com/xap/1.0/mm/"
xmlns:stRef="http://ns.adobe.com/xap/1.0/sType/ResourceRef#"
xmlns:stEvt="http://ns.adobe.com/xap/1.0/sType/ResourceEvent#">
<xmpMM:DocumentID>xmp.did: … ETC…</xmpMM:DocumentID>
<xmpMM:InstanceID>xmp.iid: …ETC… </xmpMM:InstanceID>
<xmpMM:OriginalDocumentID/>
<xmpMM:DerivedFrom rdf:parseType="Resource">
<stRef:instanceID>6B5F4850BB0819F254E40401F67ACAC9</stRef:instanceID>
<stRef:documentID>6B5F4850BB0819F254E40401F67ACAC9</stRef:documentID>
</xmpMM:DerivedFrom>
</rdf:Description>
<rdf:Description rdf:about=""
xmlns:xmp="http://ns.adobe.com/xap/1.0/">
<xmp:CreatorTool>Adobe Photoshop CS6 (Windows)</xmp:CreatorTool>
<xmp:MetadataDate>2013-09-06T15:44:49-07:00</xmp:MetadataDate>
<xmp:ModifyDate>2013-09-06T15:44:49-07:00</xmp:ModifyDate>
<xmp:CreateDate>2013-09-06T15:22:46-07:00</xmp:CreateDate>
</rdf:Description>
<rdf:Description rdf:about=""
xmlns:xmpRights="http://ns.adobe.com/xap/1.0/rights/">
<xmpRights:Marked>True</xmpRights:Marked>
<xmpRights:WebStatement>MY WEB ADDRESS</xmpRights:WebStatement>
<xmpRights:UsageTerms>
<rdf:Alt>
<rdf:li xml:lang="x-default">MY INFO HERE</rdf:li>
</rdf:Alt>
</xmpRights:UsageTerms>
</rdf:Description>
<rdf:Description rdf:about=""
xmlns:Iptc4xmpCore="http://iptc.org/std/Iptc4xmpCore/1.0/xmlns/">
<Iptc4xmpCore:IntellectualGenre/>
</rdf:Description>
<rdf:Description rdf:about=""
xmlns:photoshop="http://ns.adobe.com/photoshop/1.0/">
<photoshop:Instructions>OOOInstructions</photoshop:Instructions>
<photoshop:Headline>OOOHeadline</photoshop:Headline>
<photoshop:CaptionWriter>OOO </photoshop:CaptionWriter>
</rdf:Description>
<rdf:Description rdf:about=""
xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:format>image/jpeg</dc:format>
<dc:description>
<rdf:Alt>
<rdf:li xml:lang="x-default">OOODescription</rdf:li>
</rdf:Alt>
</dc:description>
</rdf:Description>