QMediaPlayer setPosition results in a position of 0

[szumial]

Hi! I have a program which uses the QMediaPlayer on MacOS. The logic allows me to set the current position of a local audio file by calling the setPosition function. Everything works fine when I use the functionality for the first time, but when doing it another time, the setPosition does not work. I have debugged it and it shows that the position is set to 0, even though it is getting a correct position argument. This happens regardless of using the same audio file or switching to a new one. Further debugging shows, that consecutive calls to setPosition might not be successful (or at least that is my assumption), because the QMediaPlayer::MediaStatus reports a StalledMedia status.

I am compiling my program using Qt 6.5.0 and I am using the native darwin multimedia backend on MacOS.

The same functionality works fine on Windows.

I looked for similar issues in the threads, but none of them matches my exact problem. I am running out of ideas on why this might be happening and for now it looks like something specific to the used multimedia backend. Unfortunately I cannot switch to another one (for example ffmpeg).

Here is a minimal code example:

void MyPlayer::playAudio(const QUrl &url)
{
    // Set the QUrl which is obtained from a local file
    m_player.setSource(url);

    // Set the requested position within the audio track
    // Obtained from a widget that controls the position
    if (customPositionRequested())
    {
        m_player.setPosition(customPosition);
    }

    // play audio
    m_player.play();
}

[Zbigniew-Sch]

@szumial

connect(this, &QMediaPlayer::mediaStatusChanged, this, &MyPlayer::mediaStatusChanged);

void MyPlayer::mediaStatusChanged(QMediaPlayer::MediaStatus status)
{
	if (status == QMediaPlayer::BufferedMedia)
	{
		setPosition(customPosition);
	} 
}

[szumial]

@Zbigniew-Sch does the QMediaPlayer have to be in a specific state before calling the setPosition on it? I mean, do I need to call it after calling play(), pause() or stop() first?

[mzimmers]

@szumial I don't think so. Are you sure your URL is good, and the file it points to is good, too? You might want to look at the duration property as a sanity check that what you're loading is good.

[szumial]

@mzimmers Yes, I am sure that the url is pointing to the correct source. In fact what seems strange is that the first time I call setPosition it works, but any other time, regardless of the url being identical or changed to point to a different file, it ends up being in the StalledMedia state.