I have a clip-on that I sometimes carry my phone in. When clipped in, it is not possible to interact with the screen. However, I still have access to the buttons on the side, so the double-tap to open the camera is a very useful feature and the volume buttons (either one) can then be used to take one picture or pressing both simultaneously captures a burst. However, what I would really like to do is to record video, not a still image. How can I make the double-tap switch to camera in video mode? I can't access my screen, so I can't swipe to select it, so I need the double-tap to go directly there.
I have a Nexus 6P, not rooted, Android 6.0.1.