XMP Specification September 2005 93 Embedding XMP Metadata in Application Files JPEG 5 JPEG In JPEG files, an APP1 marker designates the location of the XMP Packet. The following table shows the entry format. IMPORTANT: Following the normal rules for JPEG sections, the header plus the following data can be at most 65535 bytes long. The XMP Packet cannot be split across the multiple APP1 sections, so the size of the XMP Packet can be at most 65502 bytes. References ● JPEG File Interchange Format Version 1.02 ● ISO/IEC 10918-1 Information technology - Digital Compression and Coding of continuous-tone still images: requirements and guidelines. ● ISO/IEC 10918-4 Information technology — Digital compression and coding of continuous-tone still images: Registration of JPEG profiles, SPIFF profiles, SPIFF tags, SPIFF color spaces, APPn markers, SPIFF compression types and Registration Authorities (REGAUT) This specifies the format of APPn markers and the file interchange format. Byte Offset Field value Field name Length (bytes) Comments 0 0xFFE1 APP1 2 APP1 marker. 2 2 + length of namespace (29) + length of XMP Packet Lp 2 Size in bytes of this count plus the following two portions. 4 Null-terminated ASCII string without quotation marks. namespace 29 XMP namespace URI, used as unique ID: http://ns.adobe.com/xap/1.0/ 33 XMP Packet Must be encoded as UTF-8.