Sony a6300 iso videograph problem

[Baladeva]

hello,

i have purchase the sony 6300 ,and i shot a footage in low light.

now when i view it on my camera,my iso at 6400,4k,shutter speed at 1/50,aperture at 1.4.and there was no noise,but when i viewed it on my computer, I found so much noise on it.

it is the settings i messed up or something else?

 

thank you.