Originally Posted by Tayja
I think of it this way: dot-by-dot is like forcing the TV into native resolution
mode where each 'pixel' of the input resolution is mapped to a pixel on the
screen. Generally, only the resolution that matches the TVs native resolution
is allowed as it fills all pixels, otherwise, it'll be a smaller window within a
black screen. 1080P TVs are 1920x1080 pixels, thus dot-by-dot mode is
usually offered for 1080P material. For the other non-native resolutions,
the material is usually scaled to fit the screen to the best of the abilities.
Usually the scaling is not perfect so there's overscan. Something like that.