Robust and high-quality time-domain audio watermarking based on low-frequency amplitude modification

• Published in: IEEE transactions on multimedia Vol. 8; no. 1; pp. 46 - 59
• Main Authors: LIE, Wen-Nung, CHANG, Li-Chun
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-02-2006; Institute of Electrical and Electronic Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Amplitudes; Applied sciences; Audio signals; Audio watermarking; Auditory system; data embedding; Digital watermarking; Digital watermarks; Distortion; Ear; Electronics; Exact sciences and technology; Filtering; Humans; Information, signal and communications theory; psychoacoustic model; Psychoacoustic models; Recording and replay of audio and video signals; Robustness; Sampling; Security; Signal and communications theory; Signal processing; Signal representation. Spectral analysis; Signal, noise; Speech processing; Spread spectrum communication; Storage and reproduction of information; Telecommunications and information theory; Testing; Time domain analysis; Watermarking; Sound reproduction; Blindly; Acoustic signal; Pseudonoise; Audio watermarking; data embedding; Audiofrequency; Sound quality; Low frequency; Digital signal; Audio signal; psychoacoustic model; Audio acoustics; Digital watermarking
• ISSN: 1520-9210; 1941-0077
• DOI: 10.1109/TMM.2005.861292

This work proposes a method of embedding digital watermarks into audio signals in the time domain. The proposed algorithm exploits differential average-of-absolute-amplitude relations within each group of audio samples to represent one-bit information. The principle of low-frequency amplitude modification is employed to scale amplitudes in a group manner (unlike the sample-by-sample manner as used in pseudonoise or spread-spectrum techniques) in selected sections of samples so that the time-domain waveform envelope can be almost preserved. Besides, when the frequency-domain characteristics of the watermark signal are controlled by applying absolute hearing thresholds in the psychoacoustic model, the distortion associated with watermarking is hardly perceivable by human ears. The watermark can be blindly extracted without knowledge of the original signal. Subjective and objective tests reveal that the proposed watermarking scheme maintains high audio quality and is simultaneously highly robust to pirate attacks, including MP3 compression, low-pass filtering, amplitude scaling, time scaling, digital-to-analog/analog-to-digital reacquisition, cropping, sampling rate change, and bit resolution transformation. Security of embedded watermarks is enhanced by adopting unequal section lengths determined by a secret key.