P2: Important Description
Our app's play back video in near real-time. We're using 5.5. QML for both of them (no widgets). While Qt's animation timing is adequate for the UI on the mac, its nearly impossible to get "prefect" timing WRT the video sync. This isn't a Qt problem per se, its just that the way the mac works the only reliable method of redrawing with animation is to use a CVDisplayLink thread.
I noticed that QtMultimedia does just that for multimedia widgets which is nice. But I need to do the same for QWindow in general. In other words, being able to put QWindow in "animation mode" where it uses a CVDisplayLink call back thread to initiate and perform redraw and provides the information contained in the arguments passed to it (time of next vsync, etc).
That ability would basically allow QWindow to update precisely at each v-sync with maximum amount of time to do other things. The downside is that there would be yet another thread associated with each QWindow (if it uses "animation mode").