XMP SDK properties do not match properties displayed in Adobe Reader

[amtopel]

Sample PDF for testing: https://test.goca.io/pdf/sample_3.pdf.

If you load the sample pdf in Adobe Reader, and go to File > Properties, the properties displayed will be:
Title: PDF Metadata Sample
Author: Nigel Maddocks
Subject: Test Document
Keywords: 12345678

However, the Subject and Keywords properties are not the same when using the Adobe XMP SDK. For example, if you run the ReadingXMP sample, it will show the dc:subject as 12345678 (and it won't display any keywords).

[Priyanka-Gupta]

@amtopel
The attached file has following metadata, which I obtained using ReadingXMP sample with using PDF plugin :

Dumping XMPMeta object "" (0x0)

xmp: http://ns.adobe.com/xap/1.0/ (0x80000000 : schema)
xmp:ModifyDate = "2015-08-21T09:45:31+01:00"
xmp:CreateDate = "2015-08-21T09:42:21+01:00"
xmp:MetadataDate = "2015-08-21T09:45:31+01:00"
xmp:CreatorTool = "Acrobat PDFMaker 15 for Word"

xmpMM: http://ns.adobe.com/xap/1.0/mm/ (0x80000000 : schema)
xmpMM:DocumentID = "uuid:32f55d7c-7ef1-46ca-85c0-b5b91509ff82"
xmpMM:InstanceID = "uuid:4da38cf4-2b42-417c-b34e-f529c34ac6cc"
xmpMM:subject (0x600 : isOrdered isArray)
[1] = "1"

dc: http://purl.org/dc/elements/1.1/ (0x80000000 : schema)
dc:format = "application/pdf"
dc:title (0x1E00 : isLangAlt isAlt isOrdered isArray)
[1] = "PDF Metadata Sample" (0x50 : hasLang hasQual)
? xml:lang = "x-default" (0x20 : isQual)
dc:description (0x1E00 : isLangAlt isAlt isOrdered isArray)
[1] = "Test Document" (0x50 : hasLang hasQual)
? xml:lang = "x-default" (0x20 : isQual)
dc:creator (0x600 : isOrdered isArray)
[1] = "Nigel Maddocks"
dc:subject (0x200 : isArray)
[1] = "12345678"

pdf: http://ns.adobe.com/pdf/1.3/ (0x80000000 : schema)
pdf:Producer = "Adobe PDF Library 15.0"
pdf:Keywords = "12345678"

pdfx: http://ns.adobe.com/pdfx/1.3/ (0x80000000 : schema)
pdfx:SourceModified = "D:20150821084155"

You can use PDF_Handler plugin present ⁨XMP-Toolkit-SDK⁩ ▸ ⁨XMPFilesPlugins⁩ ▸ ⁨PDF_Handler⁩ ▸ ⁨macintosh⁩ ▸ ⁨intel_64_libcpp⁩ ▸ ⁨PDF_Handler.xpi⁩ .

Adobe reader shows Subject as “Test Document” because in this packet dc:description is Test Document. And dc:description is alias of pdf:Subject.
I hope this helps please let me know if you face any further issues.

[amtopel]

Can you explain what the PDF Plugin does that the standard XMP files library cannot do?

[Priyanka-Gupta]

@amtopel
PDF Plugin with XMPFiles does extract the embedded metadata from PDF files.
Standard Library alone will use simply packet scanner for PDF files as their is no standard handler for PDF files.

XMPFiles has support of plugins, which allows you to create
metadata-handler plug-ins that XMPFiles can load and use to handle additional
file formats. For detailed information refer https://github.com/adobe/XMP-Toolkit-SDK/blob/master/docs/XMPFilesPluginSDK.pdf.

We provide PDFHandler plugin with our SDK, if clients wish to use they can use it for PDF files.
It is present at XMPFilesPlugins/PDFHandler/ which includes compiled binaries for PDF plug-in.

To use plugins, clients should pass the path of a folder that contains file-handler plug-ins at initialization of XMPFiles.
SXMPFiles::Initialize(pluginPath);

[papitaawale]

Hi,
I want to check xmp support for reading metadata for password protected pdf file

does xmp supports reading metadata for password protected pdf file, if yes then how?

if no, then is there any other API which supports the reading of metadata for password protected pdf file? (i want to do it programmatically using c++ code + i want free sdk/api)