We present a blind watermark embedding/detection algorithm to embed watermarks into H.264's I pictures. The embedded watermark can survive H.264's compression attacks with more than a 40:1 compression ratio in I pictures. One pair of predicted discrete cosine transform (DCT) coefficients within the blocks of size 4×4 are used to embed 1-bit watermark information. The embedding locations of DCT coefficients are switched from lower subbands to higher subbands in a predefined order, while the distortions between predicted values and original values are larger than a tolerable bound. With these methods, the embedded watermarks can survive H.264's compression attacks with good invisibility.