platform-notes-windows.qdoc

Go to the documentation of this file.

// Copyright (C) 2024 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
 
/*!
\page qtmultimedia-windows.html
\title Qt Multimedia on Windows
\brief Platform notes for Windows
 
This page discusses considerations for using Qt Multimedia on Windows.
 
\section1 Notes on COM
 
Qt Multimedia uses COM APIs from the Windows platform. This requires COM
to be initialized on the threads that access Qt Multimedia APIs.
Although Qt Multimedia APIs will automatically initialize COM as needed,
we recommend initializing the QGuiApplication instance from the main
thread during application startup before making any calls to Qt
Multimedia APIs. This ensures that the main single threaded apartment
(main STA) is initialized before Qt Multimedia APIs are called from any
thread. This also guarantees that the main STA is not uninitialized
until all other apartments have shut down.
 
Qt Multimedia APIs that require COM will initialize the thread as a
single-threaded apartment by calling \c{CoInitializeEx(nullptr,
COINIT_APARTMENT_THREADED)}, and \c{CoUninitialize} will not be called
until the thread exits. This applies to the main application thread as
well, where \c{CoUninitialize} is called during the destruction of
static variables.
*/