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ICodecAPI::GetParameterRange method (strmif.h)

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[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The GetParameterRange method gets the range of values for a codec property.

This method applies only to properties whose values form a linear range.

Syntax

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

Parameters

[in] Api

Pointer to a GUID that specifies the property to query. For a list of standard codec properties, see Codec API Properties.

[out] ValueMin

Pointer to a VARIANT that receives the minimum value of the property. The caller must free the VARIANT by calling VariantClear.

[out] ValueMax

Pointer to a VARIANT that receives the maximum value of the property. The caller must free the VARIANT by calling VariantClear.

[out] SteppingDelta

Pointer to a VARIANT that receives the stepping delta, which defines the valid increments from ValueMin to ValueMax. The caller must free the VARIANT by calling VariantClear.

If the VARIANT type is VT_EMPTY, any increment is valid.

Return value

This method can return one of these values.

Return code Description
E_INVALIDARG
 Invalid argument.
S_OK
 The method succeeded.
VFW_E_CODECAPI_ENUMERATED
 The property supports a list of possible values, not a linear range.

Remarks

The valid range for the property is [ValueMin... ValueMax], with increments of SteppingDelta. If a property supports a linear range of values, the property 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
  • Floating-point types: VT_R8, VT_R4
If the property supports a list of values, instead of a range, the method returns VFW_E_CODECAPI_ENUMERATED. In that case, call ICodecAPI::GetParameterValues to get the list of values.

Requirements

Requirement Value
Minimum supported client Windows XP with SP2 [desktop apps | UWP apps]
Minimum supported server Windows Server 2003 R2 [desktop apps | UWP apps]
Target Platform Windows
Header strmif.h (include Dshow.h)
Library Strmiids.lib

See also

Codec API Reference

Encoder API

ICodecAPI