Hello,
I’ve found a memory leak caused by QMediaPlayer.

QMediaPlayer::setMedia() increases memory usage, every time its used.
Deleting player and video output is not releasing memory.

Example code :
void MainWindow::play()
{
player = new QMediaPlayer;
surface = new Surface; //implementation of QAbstractVideoSurface
player->setVideoOutput(surface);
player->setMedia((QUrl(QString("C:/file.avi")));
player->setVolume(50);
player->play();
}

void MainWindow::stop()
{
player->stop();
delete player;
delete surface;
}

invoking play() – > stop() -> play() … causes increase in memory usage.
Surface is not the issue QVideoWidged used as video output causes even more memory to be wasted.
Tested on 5.1.0 MSVC2012 64bit OpenGl
and 5.2.0 MSVC2012 64bit ANGLE