Audio watermarking algorithm against synchronization attacks using global characteristics and adaptive frame division

The technique used to hide copyright information (watermark) into the digital audio signal is termed as audio watermarking. Audio watermarking is an excellent approach to provide a solution to mitigate challenges that occur from easy copying and distribution of audio files that are being downloaded or uploaded through the web. The audio watermarking algorithms proposed earlier were implemented by image or binary logo or a unique pattern as watermark. To tackle the difficulty of online musical piracy, unethical attempt to alter purposefully copyrighted audio data and unauthorized distribution and tampering of audio files an efficient audio watermarking method is suggested here. In this method the copyright information (watermark) which is an audio signal of shorter length is imperceptibly added into the original audio signal with greater duration. Here two audio watermarking methods using DCT (Discrete Cosine Transform) and then with DWT-SVD (Discrete Wavelet Transform — singular value decomposition) methods are proposed with audio signal encrypted with secure hash algorithm as watermark. A comparative study on performance evaluation of both DCT and DWT-SVD methods are made in terms of PSNR (Peak-Signal to Noise Ratio) and MSE (Mean Square Error). The results show that transparency is best for each methods and DWT-SVD method is more efficient against signal attacks. The elementary notion of this document is to provide a beneficial and satisfactory method for secure audio file transmission by providing copyright protection.

This chapter gives an overview of the digital audio watermarking systems, including description of recently developed watermarking algorithms and an overview on the existing applications that use different audio watermarking methods. Audio watermarking algorithms are characterised by six essential properties, namely: perceptual transparency,watermark bit rate, robustness, blind/informedwatermark detection, security and computational complexity. Psychoacoustic models of the HAS that are exploited in order to preserve the subjective quality of the watermarked audio during the watermarking process are shortly reviewed. The most common watermark embedding techniques ranging from the simple LSB scheme to the various spread spectrum methods are presented. Application areas that have recently been developed and possible future applications areas are listed as well.

In this paper we propose a novel method for audio watermarking which is appropriate for real-time applications. Here the energy proportion of two successive low-middle frequency bands of each audio signal frame is computed and through the use of Index Modulation technique we embed the watermark bits into these proportion values. Low complexity is the most important characteristic of the proposed method making it appropriate for real-time applications. The method is a blind one, that is it does not need the original signal for extracting watermark bits. Experimental results have shown that it has a very good robustness against common watermarking attacks such as mp3 compression, low pass filtering, resampling, requantizing and adding noise.

Many effective watermarking algorithms have been proposed and implemented for digital images and digital video. However, a few algorithms have been proposed for audio watermarking. This is due to the fact that, human auditory system (HAS) is far more complex and sensitive than human visual system (HVS). In this research work, a new method of embedding image data into the audio signal and additive audio watermarking algorithm based on Discrete Cosine Transformation (DCT) domain is proposed. First, the original audio is transformed into DCT domain. The DCT coefficients are divided into a fixed number of subsections and the energy of each subsection is calculated. Next, watermark is generated from image by image processing algorithm. Watermarks are then embedded into selected peaks of highest energy subsection. Experimental results demonstrate that the watermark is inaudible and this algorithm is robust to common operations of digital audio signal processing, such as noise addition, re-sampling, requantization and so on. To evaluate the performance of the proposed audio watermarking method, subjective and objective quality tests including Bit Error Rate (BER) and Signal to Noise ratio (SNR) are conducted.

Using technology of wavelet decomposition and energy calculation, an audio digital watermarking algorithm was proposed. The proposed algorithm chooses mid-frequency wavelet coefficients to calculate the energy. Through the method of energy's comparison and adjustment, the watermarking information and synchronization signal were embedded into the original audio carrier with large capacity. Experimental results indicate that the proposed algorithm has a good hidden effect and an excellent robustness. Furthermore, it can be applied into air-channel transmission situation with low bit error ratio.

Audio watermarking is a method that embeds inaudible information into digital audio data. This paper proposes an audio watermarking technique for protecting audio copyrights based on human psychoacoustic model (HPM), discrete wavelet transform (DWT), neural network (NN) and error correcting code. Our technique exploits frequency perceptual masking studied in HPM to guarantee that the embedded watermark is inaudible. To assure watermark embedding and extraction, neural network is used to memorize the relationships between a Wavelet central sample and its neighbors. To increase robustness of the scheme, the watermark is refined by the Hamming error correcting code while the encoded mark is embedded as new watermark in the transformed audio signal. Our audio watermarking algorithm is robust to common audio signal manipulations like MP3 compression, noise addition, silence addition, bit per sample conversion, noise reduction, dynamic changes and Notch filtering. Furthermore, it allows blind retrieval of embedded watermark which does not need the original audio and makes the watermark perceptually inaudible.

Audio watermarking is an effective scheme for copyright protection. A robust dual watermarking scheme based on melody feature is proposed in this paper. Melody feature can be encoded for integrity verification. And then two robust watermark methods based on discrete cosine transform(DCT) and histogram are adopted to embed the watermark into the audio, which is used to resist different attacks. Tamper can be detected by comparing the melody features in the audio. In the extraction process, two groups of watermarks are extracted, and two images can be obtained. The Brenner gradient values of these two images are calculated, and the image with smaller Brenner value is selected as the final watermark image. The experimental results show that the proposed watermarking scheme has robustness to common signal processing and synchronization attacks. The robustness of the proposed watermark is better than existing algorithms.

Audio watermarking has been developed to protect the copyright of audio signals. We considered the use of the distribution of the phase spectrum and propose an effective multi-bit audio watermarking method based on phase shifting. The proposed method is implemented on the basis of a frame-wise framework. The phase spectrum of each frame is first calculated, then, in accordance with the embedded bit number of each frame, the phase bins are segmented into several subsets. An artificial phase pattern is constructed in one of these subsets to carry a specific multi-bit watermark. In the water-mark extraction process, each frame is synchronized by identifying the phase pattern, then watermarks are extracted. We investigate the performance of the proposed method, and the results indicated that the proposed method balances the trade-off of inaudibility and robustness. From comparative evaluations, the proposed method also performed better than several other audio watermarking methods.

A blind robust digital watermarking using invariant exponent moments

Filtering processing is a kind of typical and serious attack on the audio watermarking algorithm. Based on the computation in time domain before and after attacking on the audio, the mean and the standard deviation show good invariant statistical feature. The relation of four consecutive bins in a histogram can keep the change within plusmn5%. A data range selection approach, which meets the demands of normal distribution, is created generally for the watermark hiding. Based on segmenting idea, an audio watermarking algorithm is designed with statistical features by the stable relation of four consecutive bins. Experimental results show that the algorithm can resist on the attack of low pass filtering with large hiding bandwidth up to 17 bit/s. It shows much better than the existed histogram approach with relations of three consecutive bins.

In this paper, the authors present digital audio watermarking techniques that can be used for source origin authentication in real-time Session Initiation Protocol (SIP) Communications, such as Voice over IP (VoIP). The watermark-enabled VoIP mechanism utilizes audio watermarking techniques as a covert channel between calling parties to send source origin indicator information during the transportation phase of VoIP. The effects of audio watermarking were measured using the Signal-to-Noise Ratio, watermark extract durations and the effects of a-law, u-law and GSM encoding during the transportation phase of VoIP. Moreover, various audio watermarking algorithms were implemented to demonstrate the applicability of aforementioned security solution in terms of certain parameters: robustness, evaluation times, complexity and capacity. The experimental results suggest that some watermarking algorithms are applicable in VoIP, while others are not suitable for source origin authentication. © 2011 IEEE.

How to perform the audio watermarking algorithm in the DSP chip, and how to load and deal with real-time audio watermarking are two points that this paper focuses on. A real-time processing for fast audio watermarking algorithm is mentioned in this paper. The algorithm is available for the implementation in DSK5402. Experimental data shows the algorithm has good robustness and transparency in audio watermark processing.

De-synchronizing operations such as insertion, deletion, and warping pose significant challenges for watermarking. Because these operations are not typical for classical communications, watermarking techniques such as spread spectrum can perform poorly. Conversely, specialized synchronization solutions can be challenging to analyze/ optimize. This paper addresses desynchronization for blind spread spectrum watermarks, detected without reference to any unmodified signal, using the robustness properties of short blocks. Synchronization relies on dynamic time warping to search over block alignments to find a sequence with maximum correlation to the watermark. This differs from synchronization schemes that must first locate invariant features of the original signal, or estimate and reverse desynchronization before detection. Without these extra synchronization steps, analysis for the proposed scheme builds on classical SS concepts and allows characterizes the relationship between the size of search space (number of detection alignment tests) and intrinsic robustness (continuous search space region covered by each individual detection test). The critical metrics that determine the search space, robustness, and performance are: time-frequency resolution of the watermarking transform, and blocklength resolution of the alignment. Simultaneous robustness to (a) MP3 compression, (b) insertion/deletion, and (c) time-scale modification is also demonstrated for a practical audio watermarking scheme developed in the proposed framework.

Most of published audio watermark algorithms are suffered a trade-off between inaudibility and detectibility, and the detection performance depends greatly on the strength of noise added by communication channels. This work introduces an audio watermarking method that can overcome this challenge, i.e. allows increasing watermark strength while preserving inaudibility. The scheme uses psychoacoustic masking compatible to MPEG layer 1 Model 1 and adjusts it in a data adaptive way. A blind watermark extraction technique using the Independent Component Analysis (ICA) is shown to minimize the watermark decoding error. An implementation of a simple quantization-based watermarking algorithm (LSB) on the Spartan-3 FPGA Starter Kit of Xilinx is also presented as a part of hardware demonstration of the method.

This paper proposes an high embedding capacity symbol based audio watermarking process. The traditional watermark embedding processes require longer duration audio sequence in order to accommodate all the input watermark bits. Shorter duration audio sequences which are like advertisements in Television a Radio should allow the embedding of a complete watermark at least once to be able to correctly identify the owner or content. A symbol based approach for spread spectrum based audio watermark methods has been proposed in order to reduce the required size of the audio sequences for watermarking. Each group of watermark bits called as a symbol are mapped to a unique pseudo-random sequence. These PN sequence are used for actual embedding in Spread Spectrum based watermarking technique. This process while reducing the size of the audio sequence required, it also helps in reducing the errors in longer duration audio as it can allow redundant addition of watermark. An error correction method is also added to further reduce the symbol errors that are caused due to the intentional and unintentional watermark removal attacks.