Creating the new thread, as a rule.
If to try to open any other activity by StartActivity - Camera2 sample in video mode stops the video preview, and (when go back to the Main camera activity) it cannot be reset until the app full restart.
My old first project (where i moved the code from your sample into my project) is still with this trouble, but the new remade version basing on your example (where i moved my code into your example) is OK for the preview restoring at Release.
Anyway the events "camera_previewcapturecomplete" is always ignored when StartActivity, but going back is correct in your sample. No idea what is the difference.
But solved, thanks.