METHOD AND APPARATUS FOR WATERMARKING VIDEO IMAGES

摘要

Embedding a watermark in an image by changing selected DCT coefficients (301) in the blocks and macro blocks of coefficients which represent the image. The changes in the blocks that comprise each macro block are done in a coordinated manner so that the phase of the watermark signal is preserved across the block boundaries. The bit rate of the image signal is preserved by maintaining a count that represents the amount that the bit rate has been increased by changes in coefficients less the amount that the bit rate has been decreased by changes in the coefficients.