In iOS if the application is already in the background then it will not play the audio due to lacking support for this. If the application is active and then moved into the background then this works fine. Implementing the audioRole in QMLs Audio type would help with getting this working.
|For Gerrit Dashboard: QTBUG-69949|
|298891,3||AVF: Set playback audio session category while playing||dev||qt/qtmultimedia||Status: MERGED||+2||0|