Enhanced Image Trans-coding Using Reversible Data Hiding The primary application of watermarking and data hiding is for authentication, or to prove the ownership of digital media. In this paper, a new trans-coding system with the help of the technique of watermarking and data hiding is proposed. Side information is extracted before the image transcoding, such as resizing. In this paper, we focus on the problem of resizing in “thin edge” region. “Thin edge” structure normally cannot preserve after resizing process and become discrete. As the “thin edge” region is difficult to analyze real time and with a high degree of accuracy, data hiding can be used. The information of the “thin edge” region is generated and embedding into the multimedia content in encoder. Experimental results shown that there is a great improvement in the visual quality by using side information.