This guy has an alternative way of getting the same effect. Might be worth checking out to.
To summarize the video though:Create a Render Texture (right click in Assets > Create > Render Texture)
Change the size of the Render Texture to 64x64 (or whichever resolution you want)
Apply the texture to your Camera
Create a Raw Image UI element (GameObject > UI > Raw Image)
Resize the Raw Image to fit the whole canvas
Apply the texture to the raw image.