For a long time many have said Mobile==short form video and TV==long form.
Gerd picks up on the concept of how people viewing modes is bifurcating with the Internet clearly supporting both short and long form.
I’m inclined to agree on the concept that it is driven by the viewer’s situation. Do different devices (based on screen size?) lend themselves to different length of programs? Of course not. It’s about;
a) location – where am I when I want to watch something – what devices are available to me?
b) display – what device suits my current desire for experience?