QNX: Video playback fails

Qt Example qmlvideo (multimedia/video/qmlvideo/qmlvideo.pro) fails to play videos on QNX.

Error messages:

 
"mmr_output_attach() for audio failed: MMR_ERROR_OUTPUT_UNAVAILABLE (code 12)" 
qml: [qmlvideo] VideoItem.onError error 12 errorString mmr_output_attach() for audio failed: MMR_ERROR_OUTPUT_UNAVAILABLE (code 12) 
qml: [qmlvideo] Content.onFatalError 

Steps to reproduce:
1. Launch Qt qmlvideo example application
2. Play Big Buck Bunny video file

Expected outcome:
Video playback succeeds

Actual outcome:
Video playback fails

OS version:
QNX Neutrino 6.6

Notes:
Audio and video works on the device with mmrplay tool.
$ mmrplay -v screen: <filename>