Watermarking Algorithm Research Based On H.264/AVC Standard

With the rapid development of the Internet and the technology of Multi-media, the applicationof digital multimedia technology which including images, audio, and video, made greatachievements. Digital watermarking technology is the useful solution to solve the problem ofinformation integrity and copyright protection issues. Since the video has large amount ofinformation and real-time properties, the watermarking technology is both a difficulty and focus ofthe study. H.264/AVC is the new generation video compression coding standard with networkadaptability, high compression ratio and the image quality is good. In this thesis, based on theanalysis of the H.264/AVC standard as well as the existing watermark embedding algorithm andmaking full use of the I frame DCT coefficients, a variety of watermarking algorithms are discussed.The most research work and innovation points of this thesis are as follows:1.The thesis discusses the digital video watermarking technique, which including the basicconcepts and technical requirement, typical application and present research situation, and analyzesthe key technology of H.264/AVC video compression standard, such as encoders and decoders,frame structure of internal prediction, discrete cosine transform(DCT) and quantization, entropycoding. On this base, thesis introduces some fragile video watermarking algorithm which based onH.264/AVC standard I-frame DCT coefficient after quantification, and analyzes advantages anddisadvantages of the algorithm.2.For video coding standard H.264/AVC and codec structures, a robust video watermarkalgorithm based on DCT quantization coefficients of the I-frame compression domain is proposed.The proposed algorithm uses the low frequency quantized DCT coefficients in the size of thestatistical properties, sets two parameters to select DCT blocks and embeds the watermark into theI-frame DCT quantized coefficients by changing the maximum and minimum value of thecoefficients. Simulation results show that the proposed algorithm has a smaller change in bit-rateand better robustness.3. Combining with H.264/AVC video coding characteristics, a novel fragile watermarkingalgorithm which can locate the tamper with structure characteristics is proposed. Choosing the mostactive4×4DCT block of the macroblock, and use difference between the DCT block positioninformation in the macroblock and the last non-zero quantitative coefficient of the DCT block, andthrough the LSB replacement method, the watermark information is embedded into the lastnon-zero coefficient of selected block, then DCT quantized coefficients which are embedded by watermark are wrote to the bit stream. In non-interference case, the decoder using the restoremodule can extract the watermark and restore video without distortion. Otherwise, the algorithmcan locate the tampered region. The experiment results show that the proposed algorithm can locatethe tampered area effectively and has little effect on bit-rate.