This method is used when the user wants to override the existing filters in the internal filter graph built by DicomObjects, for the image rendering.
The following picture shows what happens internally with DicomObjects when a FileImport is called. It creates a Source Filter and a Sink, each with a Pin. Then DicomObjects is asking DirectShow to try to connect them, using whatever filters available.
As shown in the above picture, a list of filters (Filter 1 to Filter n) might be used by DirectShow, in order to connect the source and the sink. AddExplicitDirectShowFilter provides a means to add particular filters to this list before those pins are connected. Bear in mind that there is NO guarantee that the DirectShow internal rules will use every filter added using this mechanism, but in general all explicitly added filters do get used where possible.
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