Формат звука по умолчанию

procedure TfmMain.GetInfo;
const
  PKEY_AudioEngine_DeviceFormat_GUID: TGUID = '{F19F064D-082C-4E27-BC73-6882A1BB8E4C}';
  PKEY_AudioEngine_DeviceFormat_pid = 0;
// DEFINE_PROPERTYKEY(PKEY_AudioEngine_DeviceFormat, 0xf19f064d, 0x82c, 0x4e27, 0xbc, 0x73, 0x68, 0x82, 0xa1, 0xbb, 0x8e, 0x4c, 0);
var
  FMMDevEnum: IMMDeviceEnumerator;
  FMMDev: IMMDevice;
  FEndpoint: IPropertyStore;
  PropVar: ^tag_inner_PROPVARIANT;
  PropVar2: tag_inner_PROPVARIANT;
  Key: _tagpropertykey;
begin
  PropVar := nil;
  CoCreateInstance(CLASS_MMDeviceEnumerator, nil, CLSCTX_ALL, IID_IMMDeviceEnumerator,
    FMMDevEnum);
 
  FMMDevEnum.GetDefaultAudioEndpoint(eRender, eMultimedia, FMMDev);
  FMMDev.Activate(IID_IPropertyStore, CLSCTX_ALL, PropVar^, Pointer(FEndPoint));
 
  Key.fmtid := PKEY_AudioEngine_DeviceFormat_GUID;
  Key.pid := PKEY_AudioEngine_DeviceFormat_pid;
 
// ЗДЕСЬ ВОЗНИКАЕТ ИСКЛЮЧЕНИЕ (EAccessViolation):
  FEndPoint.GetValue(Key, PropVar2);
end;

procedure TfmMain.GetInfo;
const
  PKEY_AudioEngine_DeviceFormat_GUID: TGUID = '{F19F064D-082C-4E27-BC73-6882A1BB8E4C}';
  PKEY_AudioEngine_DeviceFormat_pid = 0;
// DEFINE_PROPERTYKEY(PKEY_AudioEngine_DeviceFormat, 0xf19f064d, 0x82c, 0x4e27, 0xbc, 0x73, 0x68, 0x82, 0xa1, 0xbb, 0x8e, 0x4c, 0);
  STGM_READ = 0;
var
  FMMDevEnum: IMMDeviceEnumerator;
  FMMDev: IMMDevice;
  FEndPoint: IPropertyStore;
  Prop: tag_inner_PROPVARIANT;
  Key: _tagpropertykey;
  Format: TWaveFormatEx;
 
begin
  CoCreateInstance(CLASS_MMDeviceEnumerator, nil, CLSCTX_ALL, IID_IMMDeviceEnumerator, FMMDevEnum);
 
  FMMDevEnum.GetDefaultAudioEndpoint(eRender, eMultimedia, FMMDev);
  FMMDev.OpenPropertyStore(STGM_READ, FEndPoint);
 
  Key.fmtid := PKEY_AudioEngine_DeviceFormat_GUID;
  Key.pid := PKEY_AudioEngine_DeviceFormat_pid;
 
//  FillChar(Prop, SizeOf(Prop), 0);
  FEndPoint.GetValue(Key, Prop);
  Move(Prop.__MIDL____MIDL_itf_mmdeviceapi_0003_00810001.blob.pBlobData^, Format, SizeOf(Format));
 
  Edit1.Text := IntToStr(Format.nChannels);
  Edit2.Text := IntToStr(Format.nSamplesPerSec);
  Edit3.Text := IntToStr(Format.wBitsPerSample)
end;