Comment 0 for bug 1619556

[Description]

During video playback a very disturbing bug occurs: the video area is always on top every other window.
The video also won't scale when changing the size of the player window.
This is not player-specific as both SMPlayer and VLC are affected.
The bug doesn't register on screenshots so I had to take a photo of the screen to illustrate:

https://ubuntu-mate.community/uploads/default/original/2X/c/ceba93ba6a7025cba79779bd92288cab92e09f3c.jpg

ouroumov@Bloc:~/Desktop$ lsb_release -rd
Description: Ubuntu 16.04.1 LTS
Release: 16.04

ouroumov@Bloc:~/Desktop$ apt-cache policy xorg xserver-xorg-video-intel
xorg:
  Installed: 1:7.7+13ubuntu3
  Candidate: 1:7.7+13ubuntu3
  Version table:
 *** 1:7.7+13ubuntu3 500
        500 http://fr.archive.ubuntu.com/ubuntu xenial/main amd64 Packages
        100 /var/lib/dpkg/status
xserver-xorg-video-intel:
  Installed: 2:2.99.917+git20160325-1ubuntu1.1
  Candidate: 2:2.99.917+git20160325-1ubuntu1.1
  Version table:
 *** 2:2.99.917+git20160325-1ubuntu1.1 500
        500 http://fr.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     2:2.99.917+git20160325-1ubuntu1 500
        500 http://fr.archive.ubuntu.com/ubuntu xenial/main amd64 Packages

ouroumov@Bloc:~/Desktop$ inxi -MCSG
System: Host: Bloc Kernel: 4.4.0-36-generic x86_64 (64 bit)
           Desktop: MATE 1.12.1 Distro: Ubuntu 16.04 xenial
Machine: System: Dell product: OptiPlex 7440 AIO
           Mobo: Dell model: 0X2MKR v: A00
           Bios: Dell v: 1.4.7 date: 03/15/2016
CPU: Quad core Intel Core i5-6500 (-MCP-) cache: 6144 KB
           clock speeds: max: 3600 MHz 1: 1239 MHz 2: 1929 MHz 3: 1974 MHz
           4: 1398 MHz
Graphics: Card: Intel Sky Lake Integrated Graphics
           Display Server: X.Org 1.18.3 drivers: intel (unloaded: fbdev,vesa)
           Resolution: 1920x1080@60.00hz
           GLX Renderer: Mesa DRI Intel HD Graphics 530 (Skylake GT2)
           GLX Version: 3.0 Mesa 11.2.0

Definitively related bug reports:

https://bugs.freedesktop.org/show_bug.cgi?id=94559
https://bugzilla.redhat.com/show_bug.cgi?id=1305369

Temporary workaround found in that redhat bug report to enable proper video playback in SMPlayer (Point #6 of Eric Lavarde's steps to reproduce):

- Open SMPlayer, go to Options -> Preferences
- Go to "Advanced", then to the "Options for MPlayer/mpv" tab
- add -vo gl to the (empty) option list