100 September 2005 XMP Specification Embedding XMP Metadata in Application Files PDF 5 PDF For PDF files, the XMP Packet is embedded in a metadata stream contained in a PDF object (beginning with PDF 1.4). The XMP must be encoded as UTF-8. This is a partial example of XMP metadata embedded as an XMP Packet, stored as a metadata stream: 1152 0 obj /Type /Metadata /Subtype /XML /Length 1706 stream ?xpacket begin='' id='W5M0MpCehiHzreSzNTczkc9d'? !-- The serialized RDF goes here. It has been removed for brevity. -- ?xpacket end='w'? endstream endobj PDF files that have been incrementally saved can have multiple packets that all look like the “main” XMP metadata. During an incremental save, new data (including XMP Packets) is written to the end of the file without removing the old. Top-level PDF dictionaries are also rewritten, so an application that understands PDF can check the dictionary to find only the new packet. Reference Full documentation on metadata streams in PDF files is available in the PDF Reference, Version 1.5, at http://partners.adobe.com/asn/tech/pdf/specifications.jsp AI (Adobe Illustrator) An .ai file generated by Adobe Illustrator® is in the Portable Document Format (PDF). Hence, the format for embedding XMP metadata is the same as for PDF files.