I got a new monitor last week and it came with integrated speakers, which I didn't think I would use, but it occurred to me that it would be handy to use these speakers rather than my Logitech 5.1 system when browsing the internet. I normally have the speakers off at the sub woofer for one main reason, the system uses 30 Watts in stand by, which roughly equates to £30 a year in wasted electricity and since I normally use my desktop only to watch movies or TV series this is not a major inconvenience, but sometimes it's annoying. At any rate, I was looking for a way of changing the default sound device using PowerShell, but it looks like it's not possible, however, it is possible to do it programmatically.
I'm reproducing the code here because I thought it was interesting. This is not my code, the original article can be found here.
PolicyConfig.h:
Console App Code:// ---------------------------------------------------------------------------- // PolicyConfig.h // Undocumented COM-interface IPolicyConfig. // Use for set default audio render endpoint // @author EreTIk // ---------------------------------------------------------------------------- #pragma once interface DECLSPEC_UUID("f8679f50-850a-41cf-9c72-430f290290c8") IPolicyConfig; class DECLSPEC_UUID("870af99c-171d-4f9e-af0d-e63df40c2bc9") CPolicyConfigClient; // ---------------------------------------------------------------------------- // class CPolicyConfigClient // {870af99c-171d-4f9e-af0d-e63df40c2bc9} // // interface IPolicyConfig // {f8679f50-850a-41cf-9c72-430f290290c8} // // Query interface: // CComPtr[IPolicyConfig] PolicyConfig; // PolicyConfig.CoCreateInstance(__uuidof(CPolicyConfigClient)); // // @compatible: Windows 7 and Later // ---------------------------------------------------------------------------- interface IPolicyConfig : public IUnknown { public: virtual HRESULT GetMixFormat( PCWSTR, WAVEFORMATEX ** ); virtual HRESULT STDMETHODCALLTYPE GetDeviceFormat( PCWSTR, INT, WAVEFORMATEX ** ); virtual HRESULT STDMETHODCALLTYPE ResetDeviceFormat( PCWSTR ); virtual HRESULT STDMETHODCALLTYPE SetDeviceFormat( PCWSTR, WAVEFORMATEX *, WAVEFORMATEX * ); virtual HRESULT STDMETHODCALLTYPE GetProcessingPeriod( PCWSTR, INT, PINT64, PINT64 ); virtual HRESULT STDMETHODCALLTYPE SetProcessingPeriod( PCWSTR, PINT64 ); virtual HRESULT STDMETHODCALLTYPE GetShareMode( PCWSTR, struct DeviceShareMode * ); virtual HRESULT STDMETHODCALLTYPE SetShareMode( PCWSTR, struct DeviceShareMode * ); virtual HRESULT STDMETHODCALLTYPE GetPropertyValue( PCWSTR, const PROPERTYKEY &, PROPVARIANT * ); virtual HRESULT STDMETHODCALLTYPE SetPropertyValue( PCWSTR, const PROPERTYKEY &, PROPVARIANT * ); virtual HRESULT STDMETHODCALLTYPE SetDefaultEndpoint( __in PCWSTR wszDeviceId, __in ERole eRole ); virtual HRESULT STDMETHODCALLTYPE SetEndpointVisibility( PCWSTR, INT ); }; interface DECLSPEC_UUID("568b9108-44bf-40b4-9006-86afe5b5a620") IPolicyConfigVista; class DECLSPEC_UUID("294935CE-F637-4E7C-A41B-AB255460B862") CPolicyConfigVistaClient; // ---------------------------------------------------------------------------- // class CPolicyConfigVistaClient // {294935CE-F637-4E7C-A41B-AB255460B862} // // interface IPolicyConfigVista // {568b9108-44bf-40b4-9006-86afe5b5a620} // // Query interface: // CComPtr[IPolicyConfigVista] PolicyConfig; // PolicyConfig.CoCreateInstance(__uuidof(CPolicyConfigVistaClient)); // // @compatible: Windows Vista and Later // ---------------------------------------------------------------------------- interface IPolicyConfigVista : public IUnknown { public: virtual HRESULT GetMixFormat( PCWSTR, WAVEFORMATEX ** ); // not available on Windows 7, use method from IPolicyConfig virtual HRESULT STDMETHODCALLTYPE GetDeviceFormat( PCWSTR, INT, WAVEFORMATEX ** ); virtual HRESULT STDMETHODCALLTYPE SetDeviceFormat( PCWSTR, WAVEFORMATEX *, WAVEFORMATEX * ); virtual HRESULT STDMETHODCALLTYPE GetProcessingPeriod( PCWSTR, INT, PINT64, PINT64 ); // not available on Windows 7, use method from IPolicyConfig virtual HRESULT STDMETHODCALLTYPE SetProcessingPeriod( PCWSTR, PINT64 ); // not available on Windows 7, use method from IPolicyConfig virtual HRESULT STDMETHODCALLTYPE GetShareMode( PCWSTR, struct DeviceShareMode * ); // not available on Windows 7, use method from IPolicyConfig virtual HRESULT STDMETHODCALLTYPE SetShareMode( PCWSTR, struct DeviceShareMode * ); // not available on Windows 7, use method from IPolicyConfig virtual HRESULT STDMETHODCALLTYPE GetPropertyValue( PCWSTR, const PROPERTYKEY &, PROPVARIANT * ); virtual HRESULT STDMETHODCALLTYPE SetPropertyValue( PCWSTR, const PROPERTYKEY &, PROPVARIANT * ); virtual HRESULT STDMETHODCALLTYPE SetDefaultEndpoint( __in PCWSTR wszDeviceId, __in ERole eRole ); virtual HRESULT STDMETHODCALLTYPE SetEndpointVisibility( PCWSTR, INT ); // not available on Windows 7, use method from IPolicyConfig };
#include "stdio.h" #include "wchar.h" #include "tchar.h" #include "windows.h" #include "Mmdeviceapi.h" #include "PolicyConfig.h" #include "Propidl.h" #include "Functiondiscoverykeys_devpkey.h" HRESULT SetDefaultAudioPlaybackDevice(LPCWSTR devID) { IPolicyConfigVista *pPolicyConfig; ERole reserved = eConsole; HRESULT hr = CoCreateInstance(__uuidof(CPolicyConfigVistaClient), NULL, CLSCTX_ALL, __uuidof(IPolicyConfigVista), (LPVOID *)&pPolicyConfig); if (SUCCEEDED(hr)) { hr = pPolicyConfig->SetDefaultEndpoint(devID, reserved); pPolicyConfig->Release(); } return hr; } // EndPointController.exe [NewDefaultDeviceID] int _tmain(int argc, _TCHAR* argv[]) { // read the command line option, -1 indicates list devices. int option = -1; if (argc == 2) option = atoi((char*)argv[1]); HRESULT hr = CoInitialize(NULL); if (SUCCEEDED(hr)) { IMMDeviceEnumerator *pEnum = NULL; // Create a multimedia device enumerator. hr = CoCreateInstance(__uuidof(MMDeviceEnumerator), NULL, CLSCTX_ALL, __uuidof(IMMDeviceEnumerator), (void**)&pEnum); if (SUCCEEDED(hr)) { IMMDeviceCollection *pDevices; // Enumerate the output devices. hr = pEnum->EnumAudioEndpoints(eRender, DEVICE_STATE_ACTIVE, &pDevices); if (SUCCEEDED(hr)) { UINT count; pDevices->GetCount(&count); if (SUCCEEDED(hr)) { for (int i = 0; i < count; i++) { IMMDevice *pDevice; hr = pDevices->Item(i, &pDevice); if (SUCCEEDED(hr)) { LPWSTR wstrID = NULL; hr = pDevice->GetId(&wstrID); if (SUCCEEDED(hr)) { IPropertyStore *pStore; hr = pDevice->OpenPropertyStore(STGM_READ, &pStore); if (SUCCEEDED(hr)) { PROPVARIANT friendlyName; PropVariantInit(&friendlyName); hr = pStore->GetValue(PKEY_Device_FriendlyName, &friendlyName); if (SUCCEEDED(hr)) { // if no options, print the device // otherwise, find the selected device and set it to be default if (option == -1) printf("Audio Device %d: %ws\n",i, friendlyName.pwszVal); if (i == option) SetDefaultAudioPlaybackDevice(wstrID); PropVariantClear(&friendlyName); } pStore->Release(); } } pDevice->Release(); } } } pDevices->Release(); } pEnum->Release(); } } return hr; }
As mentioned above this is not my code, copied from here.