QMediaPlayer::setPosition() doesn't always work properly

In some cases QMediaPlayer::setPosition() doesn't work. Debugging QMediaPlayer class shows that QGstreamerPlayerSession::seek calls the following code:

if (m_playbin && m_state != QMediaPlayer::StoppedState) {
...
}

So the m_state variable has QMediaPlayer::StoppedState value, but calling QMediaPlayer::state() shows that QMediaPlayer is in QMediaPlayer::PlayingState. I think this is because QMediaPlayer::state() returns

d_func()->state

when both d_func()->state and m_state are not synchronized.

—

I have attached an example source code that shows the problem. So build it and do the following:

1. Press Open button to load a video
2. Press Play button start playing it. As you see in Player::handleStateChange() I added a code that sets the video file to playback from the middle of it. So pass it on this state cause because isSeekable() returns false and QMediaPlayer::setPosition() doesn't work
3. Press Stop button
4. Press Play again. Now in Player::handleStateChange() the code doesn't work because the internal state in QGstreamerPlayerSession is different from QMediaPlayer::state()

The video file that I tried can be found at:

http://www.polycrystal.org/lego/movies/A_New_Computer--small.ogg