Files based upon the compound file structure contain the following two RIFF chunks at their topmost level:
The CTOC chunk indexes the CGRP chunk, which contains the actual multimedia data elements. Defined using the standard chunk notation, a compound file is represented as follows:
<compound file> RIFF('type' <CTOC> <CGRP>)
where 'type' is a FOURCC indicating the file type.
This section describes the CTOC and CGRP chunks in detail.