MPEG2 (Moving Picture Experts Group 2) video watermarking realization method based on DC (Discrete Cosine) coefficient

Abstract

The invention provides an MPEG2 (Moving Picture Experts Group 2) video watermarking realization method based on a DC (Discrete Cosine) coefficient, belonging to the field of computer information security. According to the method, watermarking information is embedded into a luminance component of an I frame of an encoded video so as to ensure the robustness of a video watermarking; the last difference DC coefficient of a Y component of the last macro block of each strip which has the smallest influence on the video quality is selected at the embedding position of the watermarking, so that video data of other strips is not influenced after the DC coefficient is changed; in an embedding and extracting algorithm of the watermarking, watermarking information is embedded on the basis that encoding quantity of a DCT (Discrete Cosine Transformation) coefficient is not changed before and after the watermarking is added by combining the DC coefficient in an MPEG2 video and utilizing a Huffman difference encoding characteristic; the embedding and the extraction of the watermarking do not relate to lots of data DCT and IDCT (Inverse Discrete Cosine Transformation) conversion, quantization and inverse quantization, the complexity of a video watermarking system is reduced greatly, the embedding and extracting efficiency of the watermarking is improved and the accuracy of watermarking information extraction is enhanced.

Description

technical field [0001] The invention is an MPEG2 video watermark realization method based on DC coefficients, which performs watermark embedding and detection for videos in the MPEG2 format, and belongs to the field of computer information security. The present invention does not need to completely decode and re-encode all video data, and the amount of video data does not change before and after embedding the watermark, which solves the problem that the quality of the reconstructed video image is greatly affected by the DC component in the watermark embedding process in previous video watermarks. There is no need to introduce a complex displacement compensation system, which greatly reduces the complexity of embedding watermarks in compressed video code streams. Background technique [0002] Video watermarking is the watermark loaded on the digital video, which is an effective digital product copyright protection and data security maintenance technology. In recent years, di...

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Problems solved by technology

[0004] At present, there are many methods of embedding video watermarks, mainly including: 1. Directly embed into the original video data stream. The advantage is that there are many embedding methods, and image watermark embedding methods can be used. The disadvantage is that the video code stream is increased and the quality of the video is reduced.

Second, the watermark is embedded in the discrete cosine transform (DCT) domain of the encoding stage, which will also affect the quality of the video

3. The watermark is directly embedded in the compressed bit stream. This solution will not cause a decrease in video quality, but limits the capacity of the embedded watermark

However, due to the limitation of the compressed video format, the video watermarking algorithm is much more difficult than the image watermarking. At present, the video watermarking technology still has the following main problems: First, the imperceptibility, robustness and embedding capacity of the video watermarking The contradiction between them cannot be solved well; the second is that the video watermark needs to meet the requirements of the code rate constraints before and after the embedding of the video watermark, which makes the video watermarking algorithm more difficult; the third is the method of re-encoding after fully decoding the compressed video data and adding the watermark Can not meet the real-time requirements of video watermarking

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