An Effective Watermarking Method Based on Energy Averaging in Audio Signals

S E Tsai,S M Yang

doi:10.1155/2018/6420314

Abstract

Methods based on discrete cosine transform (DCT) have been proposed for digital watermarking of audio signals; however, the watermark is often vulnerable to data compression and signal processing. This paper presents an effective audio watermarking method by energy averaging of DCT coefficients such that an audio signal with watermark is robust to data processing. The method is to divide an audio signal into segments by three parameters defining the segment length, the segment sequence of watermark location, and the frequency range of DCT coefficients for watermark location. An error correcting code is also integrated to improve audio signal quality after watermarking. Experimental results show that the method is robust to data compression and many other kinds of signal processing. No original signal is required for decoding the watermark. Comparison of watermarking performance with a recent work validates that the watermarking method has better audio quality and higher robustness.

Highlights

Audio watermarking is currently at the forefront of technology development to detect illegal reproduction and redistribution of audio recordings
The input audio signal can be in the Windows PCM, .wav, or MPEG-1 Layer-3 (MP3) format
The results indicate that the higher L is, the better bit error rate (BER) is

Summary

Introduction

Audio watermarking is currently at the forefront of technology development to detect illegal reproduction and redistribution of audio recordings. Fallahpour and Megıas [7] embedded the watermark in FFT domain to exploit the Mathematical Problems in Engineering translation-invariant property of the Fourier transform such that the distortions in time domain can be reduced Another method was proposed to embed the watermark in the lowest DWT coefficients by energy proportion to improve robustness; the watermark is limited in size due to audio quality concerns [8]. A watermarking method based on energy averaging of DCT coefficients is presented in this paper for digital audio signals. The watermark, instead of being directly embedded in the DCT coefficients, is converted into binary bits and applied to tune the energy of audio signal in frequency domain, making it difficult, if not impossible, to detect the locations of watermark bits.

Signal Segmentation and Energy Averaging

Error Correcting and Performance Measure

Experimental Results

Conclusions

Method