IAMStats Interface

Microsoft DirectShow 9.0

IAMStats Interface

The IAMStats interface retrieves performance data from the Filter Graph Manager. Filters can use this interface to record performance data.

Filter developers: As with all Filter Graph Manager interfaces, a filter must not hold a reference count on this interface, or it will cause a circular reference count. For more information, see IBaseFilter::JoinFilterGraph.

In addition to the methods inherited from IDispatch, the IAMStats interface exposes the following methods.

Method Description
AddValue Records a new value.
get_Count Retrieves the number of statistics.
GetIndex Retrieves the index for a named statistic, or creates a new statistic.
GetValueByIndex Retrieves a statistic by index.
GetValueByName Retrieves a statistic by name.
Reset Resets all statistics to zero.


Each statistic is defined by a name and an index. Use the GetIndex method to find the index from the name. Values are always double types. The following statistics are predefined.

Name Description
RenderFile Measures the time taken by each call to IGraphBuilder::RenderFile.
ConnectDirectInternal Measures the time taken to connect two filters.
Build Mapper Cache Measures the time taken to cache information about registered filters (used by the Filter Mapper object).
Process Category CategoryName Measures the time taken to cache information about filters in a particular category, where CategoryName is the friendly name of the filter category. (See Filter Categories.)

For each of these statistics, the values represent time in milliseconds.


Header: Declared in Control.h; include Dshow.h.

Library: Use Strmiids.lib.