WASAPI: Add support for process-specific loopback capture.

Public issue https://github.com/mackron/miniaudio/issues/484

miniaudio.h

@@ -6661,6 +6661,8 @@ struct ma_device_config
         ma_bool8 noDefaultQualitySRC;       /* When set to true, disables the use of AUDCLNT_STREAMFLAGS_SRC_DEFAULT_QUALITY. */
         ma_bool8 noAutoStreamRouting;       /* Disables automatic stream routing. */
         ma_bool8 noHardwareOffloading;      /* Disables WASAPI's hardware offloading feature. */
+        ma_uint32 loopbackProcessID;        /* The process ID to include or exclude for loopback mode. Set to 0 to capture audio from all processes. */
+        ma_bool8 loopbackProcessExclude;    /* When set to true, excludes the process specified by loopbackProcessID. By default, the process will be included. */
     } wasapi;
     struct
     {
@@ -7402,6 +7404,8 @@ struct ma_device
             ma_uint32 mappedBufferPlaybackLen;
             MA_ATOMIC(4, ma_bool32) isStartedCapture;               /* Can be read and written simultaneously across different threads. Must be used atomically, and must be 32-bit. */
             MA_ATOMIC(4, ma_bool32) isStartedPlayback;              /* Can be read and written simultaneously across different threads. Must be used atomically, and must be 32-bit. */
+            ma_uint32 loopbackProcessID;
+            ma_bool8 loopbackProcessExclude;
             ma_bool8 noAutoConvertSRC;                              /* When set to true, disables the use of AUDCLNT_STREAMFLAGS_AUTOCONVERTPCM. */
             ma_bool8 noDefaultQualitySRC;                           /* When set to true, disables the use of AUDCLNT_STREAMFLAGS_SRC_DEFAULT_QUALITY. */
             ma_bool8 noHardwareOffloading;
@@ -20764,7 +20768,7 @@ done:
     return result;
 }
 
-static ma_result ma_context_get_IAudioClient_Desktop__wasapi(ma_context* pContext, ma_device_type deviceType, const ma_device_id* pDeviceID, ma_IAudioClient** ppAudioClient, ma_IMMDevice** ppMMDevice)
+static ma_result ma_context_get_IAudioClient_Desktop__wasapi(ma_context* pContext, ma_device_type deviceType, const ma_device_id* pDeviceID, PROPVARIANT* pActivationParams, ma_IAudioClient** ppAudioClient, ma_IMMDevice** ppMMDevice)
 {
     ma_result result;
     HRESULT hr;
@@ -20778,7 +20782,7 @@ static ma_result ma_context_get_IAudioClient_Desktop__wasapi(ma_context* pContex
         return result;
     }
 
-    hr = ma_IMMDevice_Activate(*ppMMDevice, &MA_IID_IAudioClient, CLSCTX_ALL, NULL, (void**)ppAudioClient);
+    hr = ma_IMMDevice_Activate(*ppMMDevice, &MA_IID_IAudioClient, CLSCTX_ALL, pActivationParams, (void**)ppAudioClient);
     if (FAILED(hr)) {
         return ma_result_from_HRESULT(hr);
     }
@@ -20786,7 +20790,7 @@ static ma_result ma_context_get_IAudioClient_Desktop__wasapi(ma_context* pContex
     return MA_SUCCESS;
 }
 #else
-static ma_result ma_context_get_IAudioClient_UWP__wasapi(ma_context* pContext, ma_device_type deviceType, const ma_device_id* pDeviceID, ma_IAudioClient** ppAudioClient, ma_IUnknown** ppActivatedInterface)
+static ma_result ma_context_get_IAudioClient_UWP__wasapi(ma_context* pContext, ma_device_type deviceType, const ma_device_id* pDeviceID, PROPVARIANT* pActivationParams, ma_IAudioClient** ppAudioClient, ma_IUnknown** ppActivatedInterface)
 {
     ma_IActivateAudioInterfaceAsyncOperation *pAsyncOp = NULL;
     ma_completion_handler_uwp completionHandler;
@@ -20828,9 +20832,9 @@ static ma_result ma_context_get_IAudioClient_UWP__wasapi(ma_context* pContext, m
     }
 
 #if defined(__cplusplus)
-    hr = ActivateAudioInterfaceAsync(iidStr, MA_IID_IAudioClient, NULL, (IActivateAudioInterfaceCompletionHandler*)&completionHandler, (IActivateAudioInterfaceAsyncOperation**)&pAsyncOp);
+    hr = ActivateAudioInterfaceAsync(iidStr, MA_IID_IAudioClient, pActivationParams, (IActivateAudioInterfaceCompletionHandler*)&completionHandler, (IActivateAudioInterfaceAsyncOperation**)&pAsyncOp);
 #else
-    hr = ActivateAudioInterfaceAsync(iidStr, &MA_IID_IAudioClient, NULL, (IActivateAudioInterfaceCompletionHandler*)&completionHandler, (IActivateAudioInterfaceAsyncOperation**)&pAsyncOp);
+    hr = ActivateAudioInterfaceAsync(iidStr, &MA_IID_IAudioClient, pActivationParams, (IActivateAudioInterfaceCompletionHandler*)&completionHandler, (IActivateAudioInterfaceAsyncOperation**)&pAsyncOp);
 #endif
     if (FAILED(hr)) {
         ma_completion_handler_uwp_uninit(&completionHandler);
@@ -20870,12 +20874,79 @@ static ma_result ma_context_get_IAudioClient_UWP__wasapi(ma_context* pContext, m
 }
 #endif
 
-static ma_result ma_context_get_IAudioClient__wasapi(ma_context* pContext, ma_device_type deviceType, const ma_device_id* pDeviceID, ma_IAudioClient** ppAudioClient, ma_WASAPIDeviceInterface** ppDeviceInterface)
+
+/* https://docs.microsoft.com/en-us/windows/win32/api/audioclientactivationparams/ne-audioclientactivationparams-audioclient_activation_type */
+typedef enum
+{
+    MA_AUDIOCLIENT_ACTIVATION_TYPE_DEFAULT,
+    MA_AUDIOCLIENT_ACTIVATION_TYPE_PROCESS_LOOPBACK
+} MA_AUDIOCLIENT_ACTIVATION_TYPE;
+
+/* https://docs.microsoft.com/en-us/windows/win32/api/audioclientactivationparams/ne-audioclientactivationparams-process_loopback_mode */
+typedef enum
+{
+    MA_PROCESS_LOOPBACK_MODE_INCLUDE_TARGET_PROCESS_TREE,
+    MA_PROCESS_LOOPBACK_MODE_EXCLUDE_TARGET_PROCESS_TREE
+} MA_PROCESS_LOOPBACK_MODE;
+
+/* https://docs.microsoft.com/en-us/windows/win32/api/audioclientactivationparams/ns-audioclientactivationparams-audioclient_process_loopback_params */
+typedef struct {
+  DWORD TargetProcessId;
+  MA_PROCESS_LOOPBACK_MODE ProcessLoopbackMode;
+} MA_AUDIOCLIENT_PROCESS_LOOPBACK_PARAMS;
+
+#if defined(_MSC_VER) && !defined(__clang__)
+    #pragma warning(push)
+    #pragma warning(disable:4201)   /* nonstandard extension used: nameless struct/union */
+#elif defined(__clang__) || (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))
+    #pragma GCC diagnostic push
+    #pragma GCC diagnostic ignored "-Wpedantic" /* For ISO C99 doesn't support unnamed structs/unions [-Wpedantic] */
+    #if defined(__clang__)
+        #pragma GCC diagnostic ignored "-Wc11-extensions"   /* anonymous unions are a C11 extension */
+    #endif
+#endif
+/* https://docs.microsoft.com/en-us/windows/win32/api/audioclientactivationparams/ns-audioclientactivationparams-audioclient_activation_params */
+typedef struct
+{
+    MA_AUDIOCLIENT_ACTIVATION_TYPE ActivationType;
+    union
+    {
+        MA_AUDIOCLIENT_PROCESS_LOOPBACK_PARAMS ProcessLoopbackParams;
+    };
+} MA_AUDIOCLIENT_ACTIVATION_PARAMS;
+#if defined(_MSC_VER) && !defined(__clang__)
+    #pragma warning(pop)
+#elif defined(__clang__) || (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))
+    #pragma GCC diagnostic pop
+#endif
+
+static ma_result ma_context_get_IAudioClient__wasapi(ma_context* pContext, ma_device_type deviceType, const ma_device_id* pDeviceID, ma_uint32 loopbackProcessID, ma_bool32 loopbackProcessExclude, ma_IAudioClient** ppAudioClient, ma_WASAPIDeviceInterface** ppDeviceInterface)
 {
+    MA_AUDIOCLIENT_ACTIVATION_PARAMS audioclientActivationParams;
+    PROPVARIANT activationParams;
+    PROPVARIANT* pActivationParams = NULL;
+
+    /* Activation parameters specific to loopback mode. */
+    if (deviceType == ma_device_type_loopback && loopbackProcessID != 0) {
+        MA_ZERO_OBJECT(&audioclientActivationParams);
+        audioclientActivationParams.ActivationType                            = MA_AUDIOCLIENT_ACTIVATION_TYPE_PROCESS_LOOPBACK;
+        audioclientActivationParams.ProcessLoopbackParams.ProcessLoopbackMode = (loopbackProcessExclude) ? MA_PROCESS_LOOPBACK_MODE_EXCLUDE_TARGET_PROCESS_TREE : MA_PROCESS_LOOPBACK_MODE_INCLUDE_TARGET_PROCESS_TREE;
+        audioclientActivationParams.ProcessLoopbackParams.TargetProcessId     = (DWORD)loopbackProcessID;
+
+        ma_PropVariantInit(&activationParams);
+        activationParams.vt             = VT_BLOB;
+        activationParams.blob.cbSize    = sizeof(audioclientActivationParams);
+        activationParams.blob.pBlobData = (BYTE*)&audioclientActivationParams;
+
+        pActivationParams = &activationParams;
+    } else {
+        pActivationParams = NULL;   /* No activation parameters required. */
+    }
+
 #if defined(MA_WIN32_DESKTOP) || defined(MA_WIN32_GDK)
-    return ma_context_get_IAudioClient_Desktop__wasapi(pContext, deviceType, pDeviceID, ppAudioClient, ppDeviceInterface);
+    return ma_context_get_IAudioClient_Desktop__wasapi(pContext, deviceType, pDeviceID, pActivationParams, ppAudioClient, ppDeviceInterface);
 #else
-    return ma_context_get_IAudioClient_UWP__wasapi(pContext, deviceType, pDeviceID, ppAudioClient, ppDeviceInterface);
+    return ma_context_get_IAudioClient_UWP__wasapi(pContext, deviceType, pDeviceID, pActivationParams, ppAudioClient, ppDeviceInterface);
 #endif
 }
 
@@ -21048,6 +21119,8 @@ typedef struct
     ma_bool32 noAutoConvertSRC;
     ma_bool32 noDefaultQualitySRC;
     ma_bool32 noHardwareOffloading;
+    ma_uint32 loopbackProcessID;
+    ma_bool32 loopbackProcessExclude;
 
     /* Output. */
     ma_IAudioClient* pAudioClient;
@@ -21101,7 +21174,7 @@ static ma_result ma_device_init_internal__wasapi(ma_context* pContext, ma_device
         streamFlags |= MA_AUDCLNT_STREAMFLAGS_LOOPBACK;
     }
 
-    result = ma_context_get_IAudioClient__wasapi(pContext, deviceType, pDeviceID, &pData->pAudioClient, &pDeviceInterface);
+    result = ma_context_get_IAudioClient__wasapi(pContext, deviceType, pDeviceID, pData->loopbackProcessID, pData->loopbackProcessExclude, &pData->pAudioClient, &pDeviceInterface);
     if (result != MA_SUCCESS) {
         goto done;
     }
@@ -21559,6 +21632,8 @@ static ma_result ma_device_reinit__wasapi(ma_device* pDevice, ma_device_type dev
     data.noAutoConvertSRC           = pDevice->wasapi.noAutoConvertSRC;
     data.noDefaultQualitySRC        = pDevice->wasapi.noDefaultQualitySRC;
     data.noHardwareOffloading       = pDevice->wasapi.noHardwareOffloading;
+    data.loopbackProcessID          = pDevice->wasapi.loopbackProcessID;
+    data.loopbackProcessExclude     = pDevice->wasapi.loopbackProcessExclude;
     result = ma_device_init_internal__wasapi(pDevice->pContext, deviceType, NULL, &data);
     if (result != MA_SUCCESS) {
         return result;
@@ -21646,6 +21721,8 @@ static ma_result ma_device_init__wasapi(ma_device* pDevice, const ma_device_conf
         data.noAutoConvertSRC           = pConfig->wasapi.noAutoConvertSRC;
         data.noDefaultQualitySRC        = pConfig->wasapi.noDefaultQualitySRC;
         data.noHardwareOffloading       = pConfig->wasapi.noHardwareOffloading;
+        data.loopbackProcessID          = pConfig->wasapi.loopbackProcessID;
+        data.loopbackProcessExclude     = pConfig->wasapi.loopbackProcessExclude;
 
         result = ma_device_init_internal__wasapi(pDevice->pContext, (pConfig->deviceType == ma_device_type_loopback) ? ma_device_type_loopback : ma_device_type_capture, pDescriptorCapture->pDeviceID, &data);
         if (result != MA_SUCCESS) {
@@ -21710,6 +21787,8 @@ static ma_result ma_device_init__wasapi(ma_device* pDevice, const ma_device_conf
         data.noAutoConvertSRC           = pConfig->wasapi.noAutoConvertSRC;
         data.noDefaultQualitySRC        = pConfig->wasapi.noDefaultQualitySRC;
         data.noHardwareOffloading       = pConfig->wasapi.noHardwareOffloading;
+        data.loopbackProcessID          = pConfig->wasapi.loopbackProcessID;
+        data.loopbackProcessExclude     = pConfig->wasapi.loopbackProcessExclude;
 
         result = ma_device_init_internal__wasapi(pDevice->pContext, ma_device_type_playback, pDescriptorPlayback->pDeviceID, &data);
         if (result != MA_SUCCESS) {