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.

Remarks

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.

Requirements

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

Library: Use Strmiids.lib.