Phonon unable to play .avi file when audio devices are disabled

The problem can be reproduced with the qmediaplayer demo. If all the audio devices are disabled (from Control Panel\All Control Panel Items\System\Device Manager) playing an .avi file will result error:

"The operation cannot be performed because the pins are not connected. (0x80040209)"

The same .avi file can be played with Windows Media Player without any problems. The qmediaplayer shows a .wmv file correctly when the audio devices are disabled.