Visible Watermarking Technique for MPEG-2 Downsampling Transcoding in the DCT Domain

1Introduction Video transcoding in Discrete Cosine Transform(DCT) domain is highly desirable in many multi mediaapplications .It converts a video streamfromone formatto another which has alower bit-rate and/or a differentsyntax to meet the requirements such as dynamicalchannel bandwidth or different monitors of end users .In this paper ,video transcoding with spatial resolutionreductionis concerned.The watermarking technique , which embeds a visibleor invisible watermarkinto the video strea…

Visible Watermarking Technique for MPEG-2 Downsampling Transcoding in the DCT Domain

To locate the right places for embedding watermark signals, and to set the proper streng-th of the embedded watermark signal are two critical problems for obtaining a robust and transpar-ent watermark in color images. In this paper, a DCT domain visible watermarking scheme based on the luminance and texture features and alligned with transcoding from MPEG-2 to MPEG-1 is proposed. In this scheme, the location of the visible watermark is chosen at the block with minimum number of nonzero DCT coefficients in the I-frames. When embedding the visible watermark(such as video DC image) into the unmarked original image,the embedding factors are determined with the local luminance feature and texture features of the original image and watemark image by utilizing DC and 3AC coefficients only. Experimental results demonstrate that the proposed scheme not only provides good fidelity and robustness against MPEG-2 downscaling transcoding,but also achieves a low Computational complexity.