diff options
| -rw-r--r-- | CMakeLists.txt | 2 | ||||
| -rw-r--r-- | src/cubeb_wasapi.cpp | 58 |
2 files changed, 57 insertions, 3 deletions
diff --git a/CMakeLists.txt b/CMakeLists.txt index 530e3a4..75955be 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -264,7 +264,7 @@ if(USE_WASAPI) target_sources(cubeb PRIVATE src/cubeb_wasapi.cpp) target_compile_definitions(cubeb PRIVATE USE_WASAPI) - target_link_libraries(cubeb PRIVATE avrt ole32 ksuser) + target_link_libraries(cubeb PRIVATE ole32 ksuser) endif() check_include_files("windows.h;mmsystem.h" USE_WINMM) diff --git a/src/cubeb_wasapi.cpp b/src/cubeb_wasapi.cpp index 01417a5..b5546c3 100644 --- a/src/cubeb_wasapi.cpp +++ b/src/cubeb_wasapi.cpp @@ -204,6 +204,11 @@ struct auto_stream_ref { cubeb_stream * stm; }; +using set_mm_thread_characteristics_function = + decltype(&AvSetMmThreadCharacteristicsA); +using revert_mm_thread_characteristics_function = + decltype(&AvRevertMmThreadCharacteristics); + extern cubeb_ops const wasapi_ops; static com_heap_ptr<wchar_t> @@ -301,6 +306,13 @@ struct cubeb { nullptr; void * output_collection_changed_user_ptr = nullptr; UINT64 performance_counter_frequency; + /* Library dynamically opened to increase the render thread priority, and + the two function pointers we need. */ + HMODULE mmcss_module = nullptr; + set_mm_thread_characteristics_function set_mm_thread_characteristics = + nullptr; + revert_mm_thread_characteristics_function revert_mm_thread_characteristics = + nullptr; }; class wasapi_endpoint_notification_client; @@ -1401,7 +1413,8 @@ static unsigned int __stdcall wasapi_stream_render_loop(LPVOID stream) /* We could consider using "Pro Audio" here for WebAudio and maybe WebRTC. */ - mmcss_handle = AvSetMmThreadCharacteristicsA("Audio", &mmcss_task_index); + mmcss_handle = + stm->context->set_mm_thread_characteristics("Audio", &mmcss_task_index); if (!mmcss_handle) { /* This is not fatal, but we might glitch under heavy load. */ LOG("Unable to use mmcss to bump the render thread priority: %lx", @@ -1509,7 +1522,7 @@ static unsigned int __stdcall wasapi_stream_render_loop(LPVOID stream) } if (mmcss_handle) { - AvRevertMmThreadCharacteristics(mmcss_handle); + stm->context->revert_mm_thread_characteristics(mmcss_handle); } if (FAILED(hr)) { @@ -1522,6 +1535,18 @@ static unsigned int __stdcall wasapi_stream_render_loop(LPVOID stream) void wasapi_destroy(cubeb * context); +HANDLE WINAPI +set_mm_thread_characteristics_noop(const char *, LPDWORD mmcss_task_index) +{ + return (HANDLE)1; +} + +BOOL WINAPI +revert_mm_thread_characteristics_noop(HANDLE mmcss_handle) +{ + return true; +} + HRESULT register_notification_client(cubeb_stream * stm) { @@ -1757,6 +1782,31 @@ wasapi_init(cubeb ** context, char const * context_name) ctx->performance_counter_frequency = 0; } + ctx->mmcss_module = LoadLibraryW(L"Avrt.dll"); + + bool success = false; + if (ctx->mmcss_module) { + ctx->set_mm_thread_characteristics = + reinterpret_cast<set_mm_thread_characteristics_function>( + GetProcAddress(ctx->mmcss_module, "AvSetMmThreadCharacteristicsW")); + ctx->revert_mm_thread_characteristics = + reinterpret_cast<revert_mm_thread_characteristics_function>( + GetProcAddress(ctx->mmcss_module, + "AvRevertMmThreadCharacteristics")); + success = ctx->set_mm_thread_characteristics && + ctx->revert_mm_thread_characteristics; + } + if (!success) { + // This is not a fatal error, but we might end up glitching when + // the system is under high load. + LOG("Could not load avrt.dll or fetch AvSetMmThreadCharacteristicsW " + "AvRevertMmThreadCharacteristics: %lx", + GetLastError()); + ctx->set_mm_thread_characteristics = &set_mm_thread_characteristics_noop; + ctx->revert_mm_thread_characteristics = + &revert_mm_thread_characteristics_noop; + } + *context = ctx; return CUBEB_OK; @@ -1813,6 +1863,10 @@ wasapi_destroy(cubeb * context) } } + if (context->mmcss_module) { + FreeLibrary(context->mmcss_module); + } + delete context; } |