- 1 year ago
How to get hardware ID when enumerating with Windows Media Foundation
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When enumerating devices with Windows Media Foundation (WMF), you can obtain hardware IDs using the following steps:
Enumerate the devices:
- Use the
IMFAttributes::SetGUID
method to set the attribute key toMF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE
. - Use the
IMFAttributes::SetGUID
method again to set the attribute value toMF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_AUDCAP_GUID
. - Use the
MFEnumDeviceSources
function to enumerate the audio capture devices.
- Use the
Retrieve the hardware ID:
- For each device, use the
IMFActivate::GetAllocatedString
method with the attribute keyMF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_VIDCAP_SYMBOLIC_LINK
to obtain the symbolic link to the device. - Once you have the symbolic link, you can use it with other Windows APIs, such as SetupAPI, to retrieve additional information about the device, including hardware IDs.
- For each device, use the
Here's a code snippet demonstrating the process:
cpp#include <mfapi.h>
#include <mfidl.h>
HRESULT GetDeviceHardwareID(IMFActivate* pActivate)
{
HRESULT hr = S_OK;
// Get the symbolic link to the device
LPWSTR pSymbolicLink = nullptr;
hr = pActivate->GetAllocatedString(MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_VIDCAP_SYMBOLIC_LINK, &pSymbolicLink, nullptr);
if (SUCCEEDED(hr))
{
// Use the symbolic link with other Windows APIs to retrieve hardware IDs
// For example, you can use SetupAPI to get the hardware IDs
// Cleanup
CoTaskMemFree(pSymbolicLink);
}
return hr;
}
void EnumerateDevices()
{
HRESULT hr = S_OK;
// Initialize Media Foundation
hr = MFStartup(MF_VERSION);
if (FAILED(hr))
{
// Error handling
return;
}
IMFAttributes* pAttributes = nullptr;
IMFActivate** ppDevices = nullptr;
UINT32 count = 0;
// Create an attribute store
hr = MFCreateAttributes(&pAttributes, 1);
if (SUCCEEDED(hr))
{
// Set the attribute to enumerate audio capture devices
hr = pAttributes->SetGUID(MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE, MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_AUDCAP_GUID);
if (SUCCEEDED(hr))
{
// Enumerate the devices
hr = MFEnumDeviceSources(pAttributes, &ppDevices, &count);
if (SUCCEEDED(hr))
{
// Iterate through the devices
for (UINT32 i = 0; i < count; i++)
{
GetDeviceHardwareID(ppDevices[i]);
// Release the device
ppDevices[i]->Release();
}
}
}
// Cleanup
pAttributes->Release();
}
// Shutdown Media Foundation
MFShutdown();
}
Note that this code snippet provides an outline of the process, and you may need to add error handling and adapt it to your specific requirements.
Remember to include the necessary header files (mfapi.h
and mfidl.h
) and link against the required libraries when compiling your code.
Additionally, you may need to use additional Windows APIs like SetupAPI (SetupDiGetDeviceProperty
) to retrieve the hardware IDs from the symbolic link obtained.