Various aspects of the inventive concept will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

According to one or more exemplary embodiments, there is provided a method of adjusting a bitrate of an image, which may include: identifying magnitudes of one or more frequency components in the image; determining a frequency filter to correspond to a difference between a current bitrate and a target bitrate of the image; and applying the determined frequency filter to the magnitudes of the one or more frequency components.

The determining the frequency filter may be performed 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.

The identifying the magnitudes of the one or more frequency components may include: performing a two-dimensional (2D) discrete cosine transformation (DCT) on the image; and arranging the magnitudes of the one or more frequency components on a 2D plane in a first direction and a second direction of the image.

The frequency filter may be configured to reduce magnitudes of frequency components other than magnitudes of frequency components existing between an origin point and a predetermined boundary line on the 2D plane, and the predetermined boundary line may be a straight line extending in a direction different from the first direction and the second direction, and the first direction and the second direction may be perpendicular to each other.