An method for encoding comprising: obtaining, according to a data length of a first overlapped portion between encoding data of a current frame and encoding data of a previous frame, first encoding data corresponding to the data length of the first overlapped portion from the previous frame, if the previous frame is encoded in a first encoding mode and the current frame is to be encoded in a second encoding mode; and encoding, in the second encoding mode, the first encoding data corresponding to the data length of the first overlapped portion from the previous frame and encoding data of the current frame. The corresponding decoding method, encoding and decoding apparatuses are also disclosed.