VLC Used to be Great
A chat session on #kubuntu quickly revealed that this is a known VLC+Qt issue. It seems to be fixed upstream, which doesn't help me yet. But people were helpful in pointing out an interesting alternative video player: SMPlayer.
VLC also had annoyed me all the time because it totally ignores both the system's audio configuration as well as all VLC-local audio settings. It insists on reverting to internal audio despite the fact that I have set my behringer USB mixer to be the main audio device.
So I said goodbye to VLC.
A Useful Video Player with A Dimwitted Name
Whoever came up with the name SMPlayer should be bound and hit hard. Okay, that may actually explain its dimwitted name.
Anyway, because Kubuntu 15.10 comes with a rather outdated version of SMPlayer, so I immediately enabled the project's own Ubuntu ppa repository.
sudo add-apt-repository ppa:rvm/smplayer
sudo apt-get update
sudo apt-get install smplayer smplayer-themes smplayer-skins
This gave me the most recent version without any installation woes. The first test drive already worked fine.
|Themed SMPlayer (Breeze Dark)|
What I really like about this media player is that it just works and keeps out of my way as good as possible. My rendered video stuff played well without any issues. The user interface can be easily reconfigure to show only what I really need.
In order to get the player blending well with the whole desktop I had to reconfigure SMPlayer in its settings to use the Breeze theme and the dark Breeze icons. Then I switched off the main and language toolbars which I don't need.
The outcome was much better than VLC's user interface ever was: SMPlayer doesn't distract me in any way because it doesn't try to enforce some project user interface identity on me when I need to really get work done. I don't want to get distracted by noisy controls and noisy colors while previewing incoming video material or checking the rendered final footage.
After all, there's a reason so many people when doing graphics and video stuff use dark-color desktop configurations. You see, one doesn't master good audio with a lot of background noise around, even when wearing closed studio headphones. Thus I keep the color noise low wherever possible.