[videodb] fix seasons update query for mysql, which doesn't like SELECT subqueries on the same table
[cleanup] followup to f86b9d2884
[videodb] fix tvshow view for mysql by utilising a subview. Thanks to @sccplg
Merge pull request #4988 from mkortstiege/threadmsgs

[cleanup] followup to f86b9d2884
Merge pull request #4985 from jmarshallnz/fix_mysql_query

[videodb] fix seasons update query for mysql
[appmessenger] fix MediaPlay regression introduced by f86b9d2
Merge pull request #4993 from mkortstiege/playfile

[appmessenger] fix playfile regression introduced by f86b9d2
ActiveAE: Add queries to determine number of channels output
[omxplayer] Make use of audio decode fast paths when downmixing

The TrueHD codec actually works in 3 stages.
It decodes the downmixed stereo.
It then decodes the differences required to produce 5.1.
It then decodes the differences required to produce 7.1.

Many users end up downmixing this 7.1 stream back to 2.0.
Much better to tell the codec we only need the 2.0 stream.

When playing a 94s duration video file on an overclocked Pi, the audio decode took:
7.1 channels: 39.6s
5.1 channels: 36.5s
2.0 channels: 23.0s

So, it's almost twice as fast to decode TrueHD when only stereo is required.
[tagloader] read popm ratings from banshee (closes #15333)
Merge pull request #4995 from mkortstiege/banshee_popm

[tagloader] read popm ratings from banshee (closes #15333)
Merge pull request #4933 from popcornmix/truhd_fast

[omxplayer] Make use of audio decode fast paths when downmixing
Ask the player which subtitle stream is played.
Store the selected subtitle index in CApplicationPlayer::SetSubtitle and nowhere else.
Ask the player if subtitles are visible.
Store the selected subtitle index in CApplicationPlayer::SetSubtitle and nowhere else.
only force visibility of subtitle if NOT available from saved DVD navigator state
make video setting consistent with current sub visibility status