Overview of Audio Watermarking Algorithm against Synchronization Attacks <s> D. Invariant Watermark Scheme <s> A robust and blind audio watermarking algorithm based on the discrete wavelet transform(DWT)is proposed in this paper as an effective way to resist the malicious de-synchronization attacks. The algorithm embeds the watermark information into the absolute average of audio low frequency coefficients in the DWT and error- correcting coding is applied in order to lower the bit error rate of watermark in extraction. Experimental results show the performance of the method is ideal against various common signal processing attacks, especially, robustness to de-synchronization attacks. <s> BIB001 </s> Overview of Audio Watermarking Algorithm against Synchronization Attacks <s> D. Invariant Watermark Scheme <s> To trade-off imperceptibility and robustness,selecting embedding frames and changing embedding in- tensity adaptively is an effective method.A definition of masking level based human hearing system is given. Embedding frames are selected and intensity is changed based on masking level.According to the feature of cep- strum coefficients,tatistical-mean manipulation method is applied.It is an adaptive embedding algorithm both in embedding location and intensity.Experiment results have shown that the algorithm is robust against most attacks including challenging time-scale modification and random cropping.Compared with SMM(Statistical Mean Ma- nipulation),BER(Bit Error Rate)was improved at least 0.25%0,and the random cropping 3(5×1000)was improved 28.5 %. <s> BIB002
By nature, the invariant watermark is to use the physical quantity which audio signal is not sensitive to various attacks to embed hiding information. In  , a synchronization invariant audio watermarking scheme based on the statistical feature manipulation in wavelet domain was proposed. The experimental results demonstrated that this algorithm was robust to common attacks, pitch shifting, random cropping, and time-scale modifications. In BIB001 , A robust and blind audio watermarking algorithm based on the discrete wavelet transform (DWT) was proposed. The algorithm embedded the watermark information into the absolute average of audio low frequency coefficients in the DWT and error-correcting coding was applied in order to lower the bit error rate of watermark in extraction. Experimental results show the performance of the method was ideal against various common signal processing attacks, especially, robustness to de-synchronization attacks. In  , based on the property that the statistical mean value of 4th level wavelet coefficients was next to zero , a bit watermarking was embedded into the audio segment , by modifying the statistical mean value of the 4th level detail wavelet coefficients . The simulated experimental results proved that the algorithm was robust. In BIB002 , the statistical-mean manipulation method was used to achieve the invariant watermarking according to the feature of cep-strum coefficients. The simulation results proved the effectiveness of the scheme. In  , taking use of the feature that relative gravity of center of audio was steady and was insensitive to Time-Scale Modification operation and other synchronization attacks to generate the watermark information. The encrypted watermark was embedded into the third level wavelet approach coefficients of audio by quantification method. Experiment results showed that the scheme had good robustness that could resist common signal processing and 20% TSM, 1/10 dithering manipulation.