Here, after about 00:30 you can see it
It seems to be caused by camera vibration and could be due to an interaction between vibration and the camera's stabilisation (in this case, Sony X3000, it was optical stabilisation only).
I tried Vegas 14's Stabilise function but it crashes the program. It just sits there, not responding to anything, but Task Manager shows it as responding OK.
Can anyone think of a way to remove the jello effect?
I might have to abandon 4K shooting and shoot in 1080P in which you can have both optical and software stabilisation. The 1080P mode, same camera, doesn't appear to show any jello