Embodiments of the present invention provide a method and an apparatus for decoding and encoding a video, and a method and an apparatus for predicting a direct current coefficient. The video decoding method includes: receiving current frame image information sent by an encoding end, where the current frame image information includes prediction value information, and the prediction value information includes at least one intra-frame direct current DC prediction value; selecting a prediction value from the at least one intra-frame DC prediction value in the prediction value information as an intra-frame DC prediction value of the current image. Through the embodiments of the present invention, flexibility of encoding and decoding a video can be improved.