Microsoft Speech Platform

ISpMMSysAudio::GetDeviceId

ISpMMSysAudio::GetDeviceId passes back the multimedia device ID being used by the audio object.

<pre IsFakePre="true" xmlns="http://www.w3.org/1999/xhtml"> <strong>HRESULT GetDeviceId(</strong> <strong> UINT</strong> *<em>puDeviceId</em> <strong>);</strong> </pre>

Parameters

• puDeviceId
  [out] Pointer receiving the device ID.

Return Values

Remarks

The default device ID for SpMMSysAudio objects that are created using CoCreateInstance is the WAVE_MAPPER. For audio objects created using an object token, the ID will always be a specific WAV-in or WAV-out device ID.

Example

The following code snippet illustrates the use of ISpMMSysAudio::GetDeviceId using CoCreateInstance.

`

// Declare local identifiers:
HRESULT                   hr = S_OK;
CComPtr<ISpMMSysAudio>    cpMMSysAudio;
UINT                      uiDeviceId;

// Create the multimedia input object.
hr = cpMMSysAudio.CoCreateInstance(CLSID_SpMMAudioIn);
if (SUCCEEDED(hr))
{
// Get the default device Id (that
// is, uiDeviceId == WAVE_MAPPER).
hr = cpMMSysAudio->GetDeviceId(&uiDeviceId;);
}
if (SUCCEEDED(hr))
{
// Do something here.
}

The following code snippet illustrates the use of ISpMMSysAudio::GetDeviceId using an ISpObjectToken

`

// Declare local identifiers:
HRESULT                       hr = S_OK;
CComPtr<ISpMMSysAudio>        cpMMSysAudio;
CComPtr<ISpObjectWithToken>   cpObjectWithToken;
CComPtr<ISpObjectToken>       cpObjectToken;
UINT                          uiDeviceId;

// Create the multimedia input object.
hr = cpMMSysAudio.CoCreateInstance(CLSID_SpMMAudioIn);
if (SUCCEEDED(hr))
{
// Get the current multimedia object's object token.
hr = cpMMSysAudio.QueryInterface(&cpObjectWithToken;);
}
if (SUCCEEDED(hr))
{
// Find the preferred multimedia object token.
hr = SpFindBestToken(SPCAT_AUDIOIN, L"Technology=MMSys", NULL, &cpObjectToken;);
}
if (SUCCEEDED(hr))
{
// Set the current multimedia object to the preferred multimedia object token.
hr = cpObjectWithToken->SetObjectToken(cpObjectToken);
}
if (SUCCEEDED(hr))
{
// Get the device id for the object (that
// is, uiDeviceId != WAVE_MAPPER).
hr = cpMMSysAudio->GetDeviceId(&uiDeviceId;);
}
if (SUCCEEDED(hr))
{
// Do stuff here.
}