NinjaTrader windows seems tricky to record / screen capture because of the technology behind the windows. I see other users have similar problems. I don't imagine the other software other than OBS would be any different. Probably putting this project on hold for now. I could simply record my whole / half screen, but ideally I would be able to record a specific window.
LF, I tried this about 2 years ago. It never worked out well enough. Files too large, CPU usage too high, window focus issues, recording software was unreliable: garble recording, freeze program or entire screen. It was all "not production trading" quality. I used all separate applications, Windows game, discord, camtasia, etc. I would recommend something very newly developed or something built into the trading software.
Most likely the issue with OBS is they (NinjaTrader) are rendering using Direct3D or something like OpenGL. So your troubleshooting would take the same steps as gamers who have black screens. https://obsproject.com/forum/threads/does-not-capture-opengl-game.40517/ If you have a NVidia card for example, you can use GeForce to stream directly to YouTube/Twitch/etc. Don't give up
I had issues when I first got my 49" screen using software which divides my screen into spaces as it wouldn't recognize Ninja windows - and had to use a special type of software. Eventually, etiher Ninja or Dell were able to adress it as it now works. I solved the black screen issue, partially, on window capture with OBS. Someone suggested to use game capture instead and that worked partially the first time, but on subsequent attempts I'm only able to record the same window (and not the one I want) and even when switching windows in OBS - nothing happens. Might have to try the Windows Game Recording tool as suggested by userque. Not a big priority anyway. Just thought it could be fun to try it out. Thanks for your suggestions.
I read that and thought my little 12.3" Surface Pro is ridiculous. But then I read this guy below: Three 49 foot monitors in his home office!