The embodiment of the invention discloses a video coding and decoding method, and a video coding and decoding device. The method disclosed by the embodiment of the invention comprises the following steps: acquiring a current image, and obtaining
motion vector precision of the current image according to the current image, wherein the
motion vector precision comprises a search step length set, and each search step length in the search step length set is smaller than a pixel unit; obtaining a current block and a
reference image of the current block; determining a search starting point in the
reference image, and searching a target integral pixel point starting from the search starting point with one pixel unit as the search step length; searching a matched block of the current block starting from the target integral pixel point according to the
motion vector precision; and obtaining motion vector information and a predicted residual
signal, and writing the information of the
reference image, the motion vector information and the predicted residual
signal in code
stream, wherein the information of the reference image is used for indicating the reference image. By adoption of the video coding and decoding method disclosed by the embodiment of the invention, coding and decoding can be carried out in combination with video characteristics.