A method of video processing for processing coding tree units and coding units, a method and appratus for decoding and encoding video using the processing.

The present invention relates to an image decoding method capable of achieving a bandwidth reduction effect of a line buffer due to an increase in an encoding tree unit size and an implementation cost reduction effect due to a decrease in a maximum encoding unit size. The image decoding method according to an embodiment of the present invention comprises the steps of: obtaining encoded tree unit information from a video stream; obtaining signaling information on the maximum encoding unit size of an encoding unit divided from an encoding tree unit; and gradually dividing the encoding tree unit according to the signaling information.