Video coding method and device and video decoding method and device

The invention discloses a video coding method and a video decoding method. The video coding method comprises the steps of dividing video frames into a plurality of non-overlapped image blocks and calculating similarities of the image blocks in a preset time period; carrying out compression coding on the video frame images according to the similarities of the image blocks, thereby generating compressed code streams and adding the corresponding compression proportion information of the video frame images to the compressed code streams; and sending the compressed code streams to which the corresponding compression proportion information of the video frame images is added to a client, and decoding the compressed code streams by the client according to the received compressed code streams to which the corresponding compression proportion information of the video frame images is added. The invention also discloses a video coding device and a video decoding device. According to the methods and the devices, the video