Microsoft DirectX 8.0

IAMVideoDecimationProperties Interface

The IAMVideoDecimationProperties interface enables an application to control where video decimation occurs. The Overlay Mixer filter implements this interface.

If a video window is smaller than the native size of the video being displayed, the video renderer must decimate the incoming video—that is, scale the video down to the smaller size. Decimation can be performed in one of the following places.

An application can call methods on this interface to select a particular decimation strategy, in order to optimize performance. However, most applications will have no occasion to use this interface. Unless your application is designed to support particular hardware, there is no reason to modify the Overlay Mixer filter's default behavior for decimation.

Methods in Vtable Order

IUnknown methodsDescription
QueryInterfaceRetrieves pointers to supported interfaces.
AddRefIncrements the reference count.
ReleaseDecrements the reference count.
IAMVideoDecimationProperties methodsDescription
QueryDecimationUsageRetrieves the current decimation strategy.
SetDecimationUsageSets the decimation strategy.

IAMVideoDecimationProperties::QueryDecimationUsage

IAMVideoDecimationProperties Interface

Retrieves the current decimation strategy.

Syntax

HRESULT QueryDecimationUsage(
    DECIMATION_USAGE *lpUsage
);

Parameters

lpUsage
[out] Pointer to a variable of type DECIMATION_USAGE that receives the decimation setting.

Return Value

Returns an HRESULT value that depends on the implementation of the interface. The Microsoft® DirectShow® implementation returns S_OK if successful, or E_FAIL or another error code otherwise.

IAMVideoDecimationProperties::SetDecimationUsage

IAMVideoDecimationProperties Interface

Sets the decimation strategy.

Syntax

HRESULT SetDecimationUsage(
    DECIMATION_USAGE Usage
);

Parameters

Usage
[in] Member of the DECIMATION_USAGE enumeration that specifies the decimation strategy.

Return Value

Returns an HRESULT value that depends on the implementation of the interface. The DirectShow implementation returns S_OK if successful, or E_INVALIDARG otherwise.