I have similar issue too, when I run only one GstGLVideoItem instance within
the app - everything works fine but after I'm trying to show two
GstGLVideoItem's - the second one gives error: Could not initialize window
Yes, everything started to work for me since release 1.14.4 (2018-10-02).
Now I successfully use multiple
qmlglsink elements in my QWidget-based application:
only one GstGLVideoItem per QML file
QWidget::createWindowContainer() for each QQuickView instance. I know using many window container instances in a QWidget-based application can greatly hurt the overall performance of the application. But it's not yet an issue for my one-two containers.
start pipeline at QQuickWindow::BeforeSynchronizingStage with scheduleRenderJob() for each