cmake_minimum_required (VERSION 3.9.5)

project (qt6mm)

set (CMAKE_AUTOMOC ON)
set (CMAKE_AUTORCC ON)

find_package(QT NAMES Qt6 REQUIRED COMPONENTS Core)
set (QT_MINIMUM_VERSION "6.5")

find_package(Qt${QT_VERSION_MAJOR} ${QT_MINIMUM_VERSION} REQUIRED
    COMPONENTS Widgets Multimedia
)

set (EXE_NAME testbug)
add_executable (${EXE_NAME} main.cpp)
target_link_libraries (${EXE_NAME} Qt::Widgets Qt::Multimedia)

#include <QApplication>
#include <QAudioOutput>
#include <QMediaPlayer>

int main(int argc, char* argv[])
{
    QApplication app(argc, argv);

    auto path = QUrl::fromLocalFile(R"path(D:\Users\Gary\Downloads\Music\sample - 副本.wav)path"); // change the path here.

    QMediaPlayer * player = new QMediaPlayer;

    QObject::connect(player, &QMediaPlayer::sourceChanged, [&player](){
        qDebug() << player->source();
    });
    QObject::connect(player, &QMediaPlayer::errorOccurred, [&player](){
        qDebug() << player->errorString();
    });

    player->setAudioOutput(new QAudioOutput);
    player->setSource(path);
    player->play();

    return app.exec();
}

"Could not open file"
QUrl("file:///D:/Users/Gary/Downloads/Music/sample - 副本.wav")