Some film speed (4)
I believe the answer is:
clip
I believe this is a double definition.
'some film' is the first definition.
(a film clip)
'speed' is the second definition.
(clip can mean something's speed)
(Other definitions for clip that I've seen before include "Film extract; rapid pace" , "Snippet of film" , "Short piece of film" , "Cut - part of film" , "Short film extract; fasten" .)