Abstract: In the multimedia content distribution and playing system, files played were limited without compromising users' experience. Firstly, binary images were selected adaptively and embedded during the intra prediction by modifying AC coefficients of specific locations. Then, the extracted watermark was matched with the binary image selected adaptively. If not matched properly, the video could not continue to be decoded and played. The experimental results demonstrate watermark algorithm has high robustness. After watermarks are embedded, video Peak Signal-to-Noise Ratio (PSNR) and rate almost remain unchanged. The proposed algorithm also has low complexity and strong practicability, and illegal videos can be filtered effectively.

Key words: H.264, steganography, authentication playing, intra prediction, symbol encoding

摘要： 针对多媒体内容分发与播放系统,在不降低用户体验的前提下限制播放内容。该方法首先自适应地选择待嵌入的二值图像,通过修改特定位置AC系数的符号在视频帧内预测中嵌入。然后在解码播放时自适应地选择待匹配的二值图像,与提取的水印进行匹配,匹配通过,才继续解码并播放视频；否则直接停止解码播放。实验结果表明,嵌入水印的算法具有较高的鲁棒性,嵌入水印前后视频峰值信噪比(PSNR)、码率基本不变。算法复杂度低,实用性强,实现了对非法视频的有效过滤。

关键词: H.264, 视频隐写, 鉴权播放, 帧内预测, 符号编码