H.264 compression bit stream oriented video watermark method

Abstract

The invention discloses an H.264 compression bit stream oriented video watermark method. The method comprises the following steps of: generating an authentication code according to a predictive mode of a 4*4 brightness block in an I film; and embedding the authentication code in the film-grade bit stream by modulating variable-length code words of some motion sub-blocks of a B film and a P film, wherein the modulation is performed based on a mapping rule between the variable-length code words and the bits to be embedded, and the mapped variable-length code words is extremely similar to the original variable-length code words. Because in the method, the video bit stream is unnecessarily pre-processed, and comparison and replacement operations are performed by selecting the proper variable-length code words only from the H.264 / AVC compression bit stream in the watermark embedding process without a huge number of operations, so that the method has the advantages of low computing complexity, high safety and high practicability, and can better meet the requirements of the real-time video processing.

Description

technical field [0001] The invention relates to a video information hiding technology, in particular to a video watermarking method for H.264 compressed bit stream. Background technique [0002] With the rapid development of multimedia network technology, the exchange of digital multimedia information, especially video information, has reached an unprecedented level. However, video information is extremely vulnerable to various unintentional or intentional tampering attacks during transmission, which makes people doubt the integrity of video information and the authenticity of content. If tampering involves important content such as national security and court evidence, it may cause more serious consequences. Therefore, how to effectively protect the authenticity and integrity of video information content in the network environment has become a research hotspot in the field of multimedia information security in recent years. Fragile watermarking, as a secure communication ...

AI Technical Summary

Problems solved by technology

However, the high-efficiency compression performance of H.264 makes it very sensitive to small changes in the coded bitstream, which makes it very difficult and challenging to implement watermarking based on the H.264 codestream

Some researchers embed watermark information by modifying the video stream of the intra-frame 16×16 encoding mode. Although this method has good imperceptibility and small bit rate changes, in the actual encoding process, the intra-frame 16×16 The macroblocks of the encoding mode are relatively rare, that is, the watermark capacity is relatively small

Another type of method is to divide the CAVLC (Context-Adaptive Variable Length Coding) code space into commonly used code spaces and unused code spaces through statistical analysis of video sequences, and then according to the bits to be embedded and The mapping relationship of the codeword space is embedded into the watermark. This method also has good imperceptibility, and the embedding capacity is relatively large. However, this method must first perform statistical analysis on the video sequence to establish the mapping regulation, and this method has a significant impact on the bit rate. also has a greater impact

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