Just a tip: If anyone is getting:

ERROR: pipeline could not be constructed: no element 'v412src'.

(or 'v412camsrc')

you have mistyped an 'l' as a '1' (i.e. you wrote the number '1' when it should have been the small caps letter 'l')

The correct spelling is: v4l2src, where the character after '4' is the letter 'l'