Use MMCSS for event mode audio device

3 files changed, 41 insertions, 1 deletions

diff --git a/src/AudioDeviceEvent.cpp b/src/AudioDeviceEvent.cpp
index b4fd323..774b74b 100644
--- a/src/AudioDeviceEvent.cpp
+++ b/src/AudioDeviceEvent.cpp
@@ -3,6 +3,15 @@
 

 namespace SaneAudioRenderer

 {

+    namespace

+    {

+        WinapiFunc<decltype(AvSetMmThreadCharacteristicsW)>

+        AvSetMmThreadCharacteristicsFunction(L"avrt.dll", "AvSetMmThreadCharacteristicsW");

+

+        WinapiFunc<decltype(AvRevertMmThreadCharacteristics)>

+        AvRevertMmThreadCharacteristicsFunction(L"avrt.dll", "AvRevertMmThreadCharacteristics");

+    }

+

     AudioDeviceEvent::AudioDeviceEvent(std::shared_ptr<AudioDeviceBackend> backend)

     {

         assert(backend);

@@ -143,7 +152,16 @@ namespace SaneAudioRenderer
 

     void AudioDeviceEvent::EventFeed()

     {

-        SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_TIME_CRITICAL);

+        HANDLE taskHandle = NULL;

+        if (AvSetMmThreadCharacteristicsFunction && AvRevertMmThreadCharacteristicsFunction)

+        {

+            DWORD taskIndex = 0;

+            taskHandle = AvSetMmThreadCharacteristicsFunction(L"Pro Audio", &taskIndex);

+            assert(taskHandle != NULL);

+        }

+

+        if (taskHandle == NULL)

+            SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_TIME_CRITICAL);

 

         while (!m_exit)

         {

@@ -172,6 +190,9 @@ namespace SaneAudioRenderer
 

             m_wake.Wait();

         }

+

+        if (taskHandle != NULL)

+            AvRevertMmThreadCharacteristicsFunction(taskHandle);

     }

 

     void AudioDeviceEvent::PushBufferToDevice()

diff --git a/src/Utils.h b/src/Utils.h
index 1a8d9a9..8b996aa 100644
--- a/src/Utils.h
+++ b/src/Utils.h
@@ -118,4 +118,22 @@ namespace SaneAudioRenderer
         }

         #endif

     }

+

+    template <typename>

+    class WinapiFunc;

+    template <typename ReturnType, typename...Args>

+    class WinapiFunc<ReturnType WINAPI(Args...)> final

+    {

+    public:

+        typedef ReturnType(WINAPI* Func)(Args...);

+        WinapiFunc(LPCWSTR dll, LPCSTR func) { m_lib = LoadLibrary(dll); m_func = (Func)GetProcAddress(m_lib, func); }

+        WinapiFunc(const WinapiFunc&) = delete;

+        WinapiFunc& operator=(const WinapiFunc&) = delete;

+        ~WinapiFunc() { FreeLibrary(m_lib); }

+        explicit operator bool() const { return !!m_func; }

+        ReturnType operator()(Args...args) const { return m_func(args...); }

+    private:

+        HMODULE m_lib = NULL;

+        Func m_func = nullptr;

+    };

 }

diff --git a/src/pch.h b/src/pch.h
index 530d9ac..7490c9a 100644
--- a/src/pch.h
+++ b/src/pch.h
@@ -8,6 +8,7 @@
 

 #include <streams.h>

 

+#include <avrt.h>

 #include <audioclient.h>

 #include <comdef.h>

 #include <malloc.h>