Sub MFAudioMixDirect( _
   ByRef _plAudioOffsetSrc As Integer, _
   ByVal _pFrameMixFrom As IMFFrame, _
   ByRef _plAudioOffsetMix As Integer, _
   ByVal _lSamplesMixMax As Integer, _
   ByVal _dblGainStartDb As Double, _
   ByVal _dblGainEndDb As Double, _
   ByVal _bSymmetricGain As Integer _
) 

void MFAudioMixDirect( 
   out int _plAudioOffsetSrc,
   IMFFrame _pFrameMixFrom,
   out int _plAudioOffsetMix,
   int _lSamplesMixMax,
   double _dblGainStartDb,
   double _dblGainEndDb,
   int _bSymmetricGain
)

procedure MFAudioMixDirect( 
   Out  _plAudioOffsetSrc: Integer;
    _pFrameMixFrom: IMFFrame;
   Out  _plAudioOffsetMix: Integer;
    _lSamplesMixMax: Integer;
    _dblGainStartDb: Double;
    _dblGainEndDb: Double;
    _bSymmetricGain: Integer
); 

void MFAudioMixDirect( 
   [PARAMFLAG::Out] int _plAudioOffsetSrc,
   IMFFrame* _pFrameMixFrom,
   [PARAMFLAG::Out] int _plAudioOffsetMix,
   int _lSamplesMixMax,
   double _dblGainStartDb,
   double _dblGainEndDb,
   int _bSymmetricGain
) 

Parameters

_plAudioOffsetSrc

audio offset for source

_pFrameMixFrom

a frame from which the mix will be implemented

_plAudioOffsetMix

audio offset for a  mix

_lSamplesMixMax

maximal number of audio samples for a mix

_dblGainStartDb

start gain in dB

_dblGainEndDb

end gain in dB

_bSymmetricGain

indicates whether symmetric gain will be used for both audio data ("1") or not ("0")

Reference

IMFFrame Interface
IMFFrame Members