Haruna: Performance issues on older and/or less powerful hardware

[George Florea Banus]

Hello,

I'm having some problems with playback stuttering
on older and/or less powerful hardware (Intel i5-4590 3.30GHz, HD 
Graphics 4600),
while in mpv (and VLC too) it plays smoothly.
I'm rendering the video in a QOpenGLFramebufferObject 
(https://invent.kde.org/multimedia/haruna/-/blob/master/src/mpvobject.cpp).

I'm thinking the problem could be what Jean-Baptiste Kempf mentions in a 
talk about VLC and Qt.
The important part starts at 40:36 and ends at 42:30 
https://youtu.be/P1qMAupb2_Y?t=2436
Basically he says that Qt's rendering loop "doesn't work for video".
VLC (the new QML version) works around this by having two windows:
a native window for the video and one for QML and making them act as one.

I would like to avoid that.
Is there anything I can do to so that the playback is on par with mpv?

----

Here is a report I made on mpv's issue tracker with more details 
https://github.com/mpv-player/mpv/issues/9417