We saw this same footage the other day, and if you follow the whole "Apollo was faked" community, you can point out how this footage shows the gas generator giving off a long flame with a black base and a sooty smoke at the tip. This is just like the Apollo rocket flame. Their contention is that the Apollo rockets were powered by small engines hidden by a flamethrower type of apparatus. Since we know the F-1 used the exhaust from the gas generators to cool the nozzles, this test proves where the smoke and flames really came from. Yet more proof Apollo was real!