We’ll work with Video Capture SDK .Net. API is the same for all SDK’s.
Video Capture SDK have OnFilterAdded control.
To get DirectShow IBaseFilter interface use code like this:
IBaseFilter baseFilter = eventArgs.Filter as IBaseFilter;
Add VisioForge.Shared assembly to your project to have DirectShow API support.
To use your custom interface you can get it using the same way, from eventArgs.Filter.
OnFilterAdded event can be called many times, check filter name to find correct interface.