Exception when playing a mpg file with webkit

[Oliver Wieland]

Kubuntu 14.10, OpenLP r2523

1. Start OpenLP
2. Play a mpeg2 video live
3. --> Exception

Traceback (most recent call last):
  File "/home/oli/Programmierung/openlp/trunk/openlp/core/common/openlpmixin.py", line 58, in wrapped
    raise e
  File "/home/oli/Programmierung/openlp/trunk/openlp/core/common/openlpmixin.py", line 54, in wrapped
    return func(*args, **kwargs)
  File "/home/oli/Programmierung/openlp/trunk/openlp/core/ui/media/mediacontroller.py", line 202, in media_state
    self.current_media_players[source].update_ui(display)
  File "/home/oli/Programmierung/openlp/trunk/openlp/core/ui/media/webkitplayer.py", line 380, in update_ui
    controller.seek_slider.setMaximum(length)
TypeError: QAbstractSlider.setMaximum(int): argument 1 has unexpected type 'NoneType'

This doesn't happen when playing a mp4 file. Also this happens only with webkit, not with vlc.

[Tomas Groth (tomasgroth)]

I can't reproduce this crash, but I attempted a fix anyway. Could you test if my branch at https://code.launchpad.net/~tomasgroth/openlp/bugfixes17 fixes the issue?

[Oliver Wieland (oliwee)]

Your branch fixed this bug for me.