Some of the MontiVision DirectShow Filters do calculations and produce results. These MontiVision DirectShow Filter provide specific interfaces to facilitate such data retrieval. Since these interfaces can be called at any stage of the graph's lifetime, a timer may be used to facilitate regular retrieval of filter data.
If however, you require results for every processed frame, the timer approach would not be appropriate. In this case the MontiVision Smart Control provides a more appropriate method in it's event interface . The _IMVSmartControlEvents::FilterEvent method is called for every filter event from a filter. In order to use this, you will need to enable the filter events with the IMVFilterEvents::Enable method. This methods returns a 'cookie' to distinguish between filter events from different MontiVision Imaging Filter.
The FindObject sample uses filter events to retrieve an object count on every frame.