A method of adjusting a bitrate of an image based includes: identifying magnitudes of one or more frequency components in the image; determining a frequency filter based on a difference between a current bitrate and a target bitrate of the image such that the greater is the difference between the current bitrate and the target bitrate, magnitudes of the more high frequency components are reduced by the frequency filter; and applying the determined frequency filter to the magnitudes of the one or more frequency components.