OM# Documentation

Reading SDIF meta-data

Extracting data from an SDIF file generally requires information about its structure and contents. The SDIF file editor is a useful means to get such information, although other utilities are also available for it. It is important to identify in particular, whether the targeted data is in a specific stream, and if it corresponds to a given type of SDIF frame or matrix.

Frame/Matrix Stream structure

The sdifinfo utility returns a list of “matrix streams”. In SDIF “streams” are determined by the type and stream ID of a sequence of frames. Here, “matrix stream” means that two different matrix types contained in a same frame stream will be reported as different elements. The mqtrix streqm info returned by sdiffinfoare therefore triplets (stream-ID, frame-type, matrix-type):

sdifinfo also prints a more detailed description in the Listener.

Note that this information aslo appears on the SDIFFILE box mini-view.

Type descriptions

sdiftypedescription is another utility reading the description of matrices or frames of a given type in the SDIF file type declarations.

Name-Value Tables

Name-Value Tables (NVT) are general textual information stored in the SDIF file header, giving all kind of contextual information about the actual contents (author or source of the file, analysis methods and parameters, etc.)

The SDIF package of OM# includes a class SDIFNVT representing this information.

The function getnvtlist returns all Name-Value Tables found in an SDIF file as a list of SDIFNVT objects. The utilities find-in-nvt and find-in-nvtlist facilitate searching specific information in it.