This paper proposes an error detection and copyrights protection scheme for MPEG-2 video based on digital watermarking algorithm using channel coding. The watermark signal is generated by applying copyrights information of video data to convolutional encoder, and it is embedded into every block in intra frames while encoding to MPEG-2 video stream. In the decoder, the embedded signal is detected from each block of intra frames, and the detected signal is used to localize errors in the video stream. The detected signal can also be used to claim ownership of the video data by decoding it to copyrights information. In this stage, errors in the detected watermark signal can be corrected by channel decoder. Experimental results show that the proposed method can detect errors in the video stream while decoding and reconstruct copyrights information more correctly than the conventional method.