Launch Monster Wars and turn off screen before the app is ready ---> the app keeps reproducing audio

same here arale/rc-proposed r174

I did some triaging of this bug quickly and discovered that media-hub wasn't being notified that the client was being suspended, which is what would cause it to pause playback. Then I discovered that during this case, the app isn't actually getting suspended like it should be. So this is the real issue, the lifecycle management isn't behaving correctly.

Can't reproduce it with r303 on Nexus 7.

Can't reproduce it with r173 on Arale (flashed today, just like the N7)

Just reproduced it on krillin with the following version info:

current build number: 192
device name: krillin
channel: ubuntu-touch/rc-proposed/bq-aquaris.en
last update: 2015-12-01 10:07:53
version version: 192
version ubuntu: 20151201
version device: 20151028-869191d
version custom: 20151111--36-46-vivid

I also just reproduced it on the Nexus 7 with r303.

confirming on krillin, rc-proposed

Finally reproduced the issue. So far I've been trying with Falldown without success.
Now that I tried with Monster Wars I was able to reproduce it.

unity8 correctly suspends MonsterWars by calling ubuntu_app_launch_pause_application("monsterwars.t-mon_MonsterWars_0.7")
It doesn't happen as soon as you turn the display off though, as unity8 has to wait until the app has finished initialing first (ie, it has draw its first frame or two). So it happens shortly after the display is turned off.

I can see it worked by running:
$ top -d 0.5 -p $(pidof MonsterWars)

"""
  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
 3886 phablet 20 0 341140 126028 43480 T 0,0 6,8 0:05.59 MonsterWars
"""

Strangely enough the music keeps playing for 10 seconds or so until if finally goes silent.

In short: qtmir (from unity8 process) is doing its part.

So the problem seems to be that whoever service is playing that audio stream doesn't stop it as soon as the originating process is suspended.

We decided this was an issue where qtmultimedia is not calling paused for the Audio element when the app becomes suspended. For the MediaPlayer element, background playback should be possible and thus needs to be controlled specifically by the application, just like mediaplayer-app does for this case when it's suspended.