The Open Packaging Convention is a specification standardized within the framework of the format of office automation documents Open XML proposed by Microsoft, and also used by the format XPS, a competitor of pdf.

It makes it possible to store in the same file at the same time binary data XML and data in a way independent - segmented structure - from/to each other. This storage system of data is very flexible and extensible - thus does not reserve itself only for the formats Open XML and XPS - and makes it possible to specify or find data in a logical way using relations.

A document respecting Open Packaging Convention is a compressed file ZIP, which makes it possible the whole of the data to be gathered within the same file and to be compressed in order to be able to exchange itself more simply.

The OPC is specified in part 2 of the standard of Open Office XML, Ecma 376.

Technique

This format defines the internal structure of any format of file by introduidant the concept of package ( package ), left ( shares ) and relations ( relationships ).

The package represents the document in itself, that is to say a document compressed with format ZIP. The left are the stored raw data in an independent way in the file, and the relations represent the bonds between the package and the parts between them.

Reference