IEncoderAPI::GetParameterRange Method

2009-01-07

Note The IEncoderAPI interface is deprecated. Use ICodecAPI instead.
The GetParameterRange method retrieves the valid range of values that the parameter supports, in cases where the parameter supports a stepped range as opposed to a list of specific values.

Syntax

HRESULT GetParameterRange(
  [in]   const GUID *Api,
  [out]  VARIANT *ValueMin,
  [out]  VARIANT *ValueMax,
  [out]  VARIANT *SteppingDelta
);

Parameters

Api [in]
Pointer to a GUID that specifies the parameter.
ValueMin [out]
Pointer to a VARIANT type that receives the minimum value of the parameter.
ValueMax [out]
Pointer to a VARIANT type that receives the maximum value of the parameter.
SteppingDelta [out]
Pointer to a VARIANT type that receives the stepping delta, which defines the valid increments from ValueMin to ValueMax.

Return Value

If the method succeeds, it returns S_OK. If it fails, it returns an HRESULT error code.

Remarks

If Api equals ENCAPIPARAM_BITRATE_MODE, the method returns E_NOTIMPL, because the bitrate mode constants are a list of specific values.

The valid range for the parameter is [ValueMin...ValueMax], with increments of SteppingDelta. If a parameter supports a stepped range of values, it must use one of the following variant types:

Unsigned types : VT_UI8, VT_UI4, VT_UI2, VT_UI1
Signed types : VT_I8, VT_I4, VT_I2
Float types : VT_R8, VT_R4

By definition, the parameter will return a specific type.

Any stepping value is valid. If the range has no stepping delta (that is, you can increment by any value), the encoder should return an empty value (VT_EMPTY) for SteppingDelta.

Requirements

Header	Declared in Strmif.h; include Dshow.h.
Library	Use Strmiids.lib.

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