MFGetAttributeRatio function (mfapi.h)

Retrieves an attribute whose value is a ratio.

Syntax

HRESULT MFGetAttributeRatio(
  [in]  IMFAttributes *pAttributes,
  [in]  REFGUID       guidKey,
  [out] UINT32        *punNumerator,
  [out] UINT32        *punDenominator
);

Parameters

[in] pAttributes

Pointer to the IMFAttributes interface of the attribute store.

[in] guidKey

GUID that identifies which value to retrieve. The attribute type must be MF_ATTRIBUTE_UINT64.

[out] punNumerator

Receives the numerator of the ratio.

[out] punDenominator

Receives the denominator of the ratio.

Return value

If this function succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.

Remarks

Some attributes specify a ratio as a packed UINT64 value. Use this function to get the numerator and denominator as separate 32-bit values.

Requirements

See also

MFSetAttributeRatio

Media Foundation Functions