[User 325245]

Raspberry Pi user here as well. It's not working for me while playing a video. 
But it shows a fixed color when the video is paused^^
@DaLanik, is there anything we could do for you to try?

 As I said, it is 100% dependable on Kodi internal "RenderCapture" command, and it that doesn't work, there's nothing I can do about it. I can only try making a test app to see if RenderCapture is really working or not...