摘要

Video watermarking technology is a useful method to track piracy for digital videos. However, most watermarking algorithms cannot be directly applied to H.264 streaming media because of their poor real-time performance, which may cause users to watch the video unsmoothly. In order to solve this problem, a real-time H.264 video watermarking algorithm (RVWA) is proposed. First, the video is segmented before embedding watermark, which makes watermark embedding and video transmission be carried on at the same time. Then, the concept of watermark embedding margin of frame (WEMF) is proposed to shorten the watermark embedding time. By calculating the value of WEMF for each B frame, which is related to its frame bits, suitable B-frames can be selected to embed watermark without decoding it completely. Finally, with the characteristic of variable macro block size in H.264 coding standard, a simplified formula is presented to quickly calculate the just noticeable difference (JND) value of the macro block, and then the macro blocks with larger JND value are selected to embed watermark into their motion vectors, which also provides good invisibility. Experimental results show that the proposed algorithm can find suitable embedding positions and embed watermark quickly with good invisibility and less increase of the bit-rate of video. RVWA algorithm can be used in stream media environment in real time.

全文