Hi, I build QGC using QT and the not so up to date explanation finded here:
Building QGC
I use QT 5.15.2 + MSVC2019_64bit release.
My goal is to build custom interface to implement external sensor to QGC stream just like Eliot report here: thank you Eliot!
The good news is that I succeeded to do the first part and I can now see “my sensor” in the instrument panel and 2 decimal, instead of 1, for the BAR30 sensor reading (something I was looking for for longtime now). I then build QGC and a installer for my field laptop and my ROV (non-blue-OS) connect to it just like usual. The only problem is that I lost the video window. And, the video setting in the QGC general application setting (usually UDP h.264 video Stream) is not available and some line are missing (UDP, aspect ratio, file format). I only see: Source and Video decode priority.
I installed gstreamer v. 1.18.1 like explained here : gstreamer for qgc and make sure it is fully installed on c:/gstreamer. I selected the 64 bit version.
I have no idea if QT use this file somehow 
and on the link above they also mention to install the gstreamer framewok (I build in Windows). I do not really know what to do with this bunch of files framework. I hope they are redundant of the gstreamer pkg?
It is a bit frustrating since I am so close to make it work.
Should I installed gstreamer like a librarie somewhere in QT? If so where? I also don’t see any build error like: cannot find gstreamer or such. Do QT need this to build?
thank you