Merging annotations in PDF using Assembler Service

Hi all,

I want to merge Annotations in pdf. For that, I am using Assembler service. DDx is as below:

<DDX xmlns="http://ns.adobe.com/DDX/1.0/">

  <PDF result="resultDoc">

    <PDF source="originalPDF"/>

    <Comments source="commentsXFDF"/>

  </PDF>

  <?ddx-source-hint name="originalPDF"?>

  <?ddx-source-hint name="commentsXFDF"?>

</DDX>

Above DDX is not working for pdfs, which are not created by Adobe(related products).  Sample Input pdf producer is "Dalim Software Applications"

Error logs are as below:

2013-10-01 00:14:21,675 WARN  [com.adobe.internal.ddxm.ddx.pdf.PDFResult] (http-0.0.0.0-8080-4) DDXM_W10001: Could not update metadata on resultDoc.pdf.

com.adobe.internal.pdfm.metadata.MetadataException: PDFM_S10004: Metadata operation "releaseMetadata/commit" failed for document "resultDoc.pdf" due to an int

ernal error ....

Caused by: com.adobe.internal.pdftoolkit.core.exceptions.PDFInvalidDocumentException: CosName expected, found class com.adobe.internal.pdftoolkit.core.cos.CosString , invalid obj number: 0, dict key: /Trapped

.....

2013-10-01 00:14:21,681 ERROR [com.adobe.internal.ddxm.Executive] (http-0.0.0.0-8080-4) DDXM_S00001: Failed to assemble result named resultDoc

com.adobe.internal.pdfm.DocumentException: ALC-ASM-S01-004: Failed to convert content for originalPDF.

Caused by: com.adobe.internal.pdftoolkit.core.exceptions.PDFUnableToCompleteOperationException: Error during commit of XMP data to PDF document.

Caused by: com.adobe.internal.pdftoolkit.core.exceptions.PDFInvalidDocumentException: CosName expected, found class com.adobe.internal.pdftoolkit.core.cos.CosString , invalid obj number: 0, dict key: /Trapped

I tried to validate metadata of the input pdf using http://www.pdflib.com/knowledge-base/xmp-metadata/free-xmp-validator/,  and the result is as follows:

XMP data is  invalid

Reason: XMP metadata: Description of extended property 'xmpMM:OriginalDocumentID' missing in embedded extension schema 'xmpMM' description

Now, if actual cause of the issue is invalid xmp data, then How can I deal this types of pdfs.

Is there any tool to repair xmp data or any thrid party library to merge all types of annotations (like text comments, stamps, file attachments , ..)  in pdf.

Please suggest