Multiple audio watermarking system based on CDMA

Abstract

Multiple watermarking is the technique that permits to embed multiple data into the same media content. In this paper, a new multiple audio watermarking system is discussed. Our main objective is to increase the capacity of watermark information, under the inaudibility constraint, while maintaining a high degree of robustness against several disturbances. At the emitter, code division multiple access (CDMA) is used to embed multiple watermarks in the time domain of the host signal. At the receiver, we consider the detection process as a matter of blind source separation (BSS) between the audio signal and the embedded data. Two BSS techniques have been tested in the new multi-watermarking system: under-determined independent subspace analysis (UISA) and Gaussian mixture models (GMM). Experimental results exhibit that inaudibility and high robustness of hidden data can be achieved simultaneously with a substantial increase of the amount of watermark information (to a multiplicative factor of 4).