Video Watermarking System Based On Android Mobile Device

The development of tele-communication technique, the widely use of mobile devices has greatly changed people life style. With kinds of mobile applications such as Youku and Wechat, people can videotape anything anytime they want and shared the video conveniently. However, the easy way of copy and delivery makes the protection of copyright to be an issue. Video watermark technique protects the copyright of digital video by embedding invisible watermark into digital videos, researchers have spent great time in this field and a lot of watermark algorithms have been proposed. However, when coming to Android devices, the limited performance of CPU and other characters make it hard to directly implement the existed algorithm on Android platform.Based on the research of Android multimedia framework and video watermark technique, this paper proposes a video watermark system based on Android devices. Firstly, this paper analyzes Android multimedia framework, especially Stagefright and OpenMAX. Then this paper reviews naive video system of Android and evaluates three different video system developing methods based on different layers of the system, including one based on third-party library, the one based on MediaCodec and one based on OpenMAX. Based on the proposed system, this paper implements an improved DCT watermark algorithm with low complexity and proposes the video watermark system on Android. The systems calls GPU to fulfill the encoding and decoding part, which is just like the native video system of Android. Besides, the algorithm module is based on an advanced blind watermark algorithm with low complexity. The system performs the watermark embedding while doing the real-time recording. The experiment results shows that this system can meet the requirements of copyright on mobile devices.